Principles: Recognition, Referral, Staging, Biopsy, Treatment, Surveillance
- MALIGNANT MUSCULOSKELETAL TUMOURS are sarcomas - malignant mesenchymal tumours of bone or soft tissue. They are rare, and rarity is precisely the hazard: the general surgeon, the general orthopaedic surgeon and the general practitioner each see them so infrequently that the default assumption is benignity. The published thresholds exist to override that default. Any soft-tissue lump that is INCREASING IN SIZE, LARGER THAN 5 CM, or DEEP TO THE DEEP FASCIA - whether or not it is painful - should be referred to a diagnostic centre as a suspected soft-tissue sarcoma (British Sarcoma Group). For bone, PAIN OR A PALPABLE MASS arising from any bone should prompt investigation, a plain radiograph is the first investigation of choice, and NIGHT PAIN is an explicit red flag.
- THE ORDER OF INVESTIGATION IS NOT NEGOTIABLE: radiograph, then local MRI of the whole lesion and compartment including the joint above and below, then chest CT for lung metastases - and biopsy LAST. Biopsy before imaging creates a haematoma that blurs tumour margins, seeds normal planes and can convert a resectable tumour into a larger resection. In bone sarcoma guidance, patients with clinicoradiological findings suggestive of a primary bone tumour should be sent to a reference centre BEFORE biopsy.
- THE HAZARDS OF BIOPSY ARE QUANTIFIED, NOT ANECDOTAL. The Musculoskeletal Tumor Society studied 329 biopsies in 1982 and repeated the exercise on 597 patients from 21 institutions, reported in 1996. In the 1996 series the diagnostic error rate was 17.8%; a biopsy problem forced a different and often more complex operation, or the use of adjunctive irradiation or chemotherapy, in 19.3% (versus 18% in 1982); the outcome changed - disability, loss of function, local recurrence or death - in 10.1% (versus 8.5% in 1982); and 18 patients underwent an unnecessary amputation (versus 15 previously). Errors, complications and changes in course and outcome were TWO TO TWELVE TIMES GREATER (p less than 0.001) when the biopsy was done at a referring institution rather than at a treatment centre.
- THE UNPLANNED ('WHOOPS') EXCISION IS THE COMMONEST REFERRAL DISASTER and it cannot be watched. Of 65 patients referred after unplanned excision of an extremity soft-tissue sarcoma - all with positive margins histologically, but NO gross residual on examination and NO tumour on cross-sectional imaging - planned re-excision found sarcoma in 23 (35%). Residual disease could not be predicted from initial size, grade, preoperative irradiation, or the interval to referral. Local recurrence occurred in 5 of those 23 (22%) versus 16 of 227 (7%) in the unit's other extremity sarcomas (p = 0.03).
- STAGING AND MARGINS USE TWO LANGUAGES. Enneking's surgical staging system stratifies by biologic grade (I low, II high, III metastatic present), by anatomic setting (A intracompartmental, B extracompartmental), and by metastasis, and it defines operative margins as INTRALESIONAL, MARGINAL, WIDE and RADICAL relative to the lesion, its reactive zone and its compartment. The AJCC/UICC TNM system grades histologically (usually FNCLCC) and adds tumour size, depth-related descriptors, nodal status and metastasis. Modern margin analysis has moved to the residual-tumour (R) classification, and a large series showed 10-year local recurrence of 8%, 21% and 44% for R0, R1 and R2 respectively.
- TREATMENT PRINCIPLE BY FAMILY: osteosarcoma - neoadjuvant and adjuvant multiagent chemotherapy (doxorubicin, high-dose methotrexate with folinic-acid rescue, cisplatin, with or without ifosfamide) around complete surgical removal of all detectable disease; Ewing sarcoma - polychemotherapy with surgery and/or radiotherapy for local control, the one sarcoma family that is genuinely radiosensitive; conventional chondrosarcoma - SURGERY, because it is relatively radiotherapy-resistant (doses above 60 Gy are needed after incomplete resection) and chemotherapy is only possibly effective in the mesenchymal subtype and of uncertain value in the dedifferentiated subtype; adult extremity soft-tissue sarcoma - surgical excision followed by radiotherapy for high-grade limb tumours, with adjuvant chemotherapy not routinely recommended.
- LIMB SALVAGE IS THE DEFAULT WHERE IT CAN ACHIEVE THE SAME MARGIN. In the randomised trial of 43 adults with high-grade extremity soft-tissue sarcoma, limb-sparing resection plus radiotherapy versus amputation gave no difference in five-year disease-free survival (71% versus 78%, p = 0.75) or overall survival (83% versus 88%, p = 0.99); the only correlate of local recurrence on multivariate analysis was the FINAL MARGIN OF RESECTION. In 227 patients with distal femoral osteosarcoma, limb salvage did not shorten the disease-free interval or compromise long-term survival compared with above-knee amputation or hip disarticulation (p = 0.8).
- SPECIALIST-CENTRE CARE IS AN EVIDENCE-BASED INTERVENTION, NOT ETIQUETTE. In a nationwide analysis of 12,528 patients, presentation to a specialised sarcoma multidisciplinary tumour board BEFORE treatment (5,281 patients, 42.2%) was associated with better compliance with clinical practice guidelines - biopsy before surgery, appropriate imaging, quality of initial surgery, fewer reoperations (all p less than 0.001) - and significantly better local relapse-free and relapse-free survival on univariate and multivariate analysis, despite that group having generally WORSE prognostic characteristics.
- “Soft-tissue lump: increasing in size, larger than 5 cm, or deep to the deep fascia - refer, painful or not.
- “Radiograph, then MRI (whole compartment, joint above and below), then chest CT. Biopsy LAST.
- “Mankin 1996: 17.8% diagnostic error, 19.3% forced a more complex operation, 10.1% changed outcome, 18 unnecessary amputations; 2-12x worse outside the treatment centre.
- “Whoops excision: 35% residual sarcoma at re-excision despite clear imaging - re-excise, never observe.
- “Conventional chondrosarcoma is neither chemosensitive nor radiosensitive - the operation IS the treatment.
- “Limb salvage does not compromise survival when the margin is equivalent (Rosenberg 1982; Simon 1986).
A deep or enlarging mass is a sarcoma until proved otherwise. In synovial sarcoma in children, only half the patients had any of the four recognised clinical features at onset, 48.5% presented with a painless mass, and in 30.3% no mass was identified at all - the presentation was an unexplained joint contracture in 21.2%. Mean duration of symptoms was 98 weeks, and the diagnosis followed an unplanned excision in 15 of 35 children.
A transverse incision, a tract crossing compartments or neurovascular planes, a drain brought out through virgin tissue, or a tumour-laden haematoma converts a limb-salvage case into an amputation. The Musculoskeletal Tumor Society quantified it: a biopsy problem forced a different or more complex operation in 19.3% and changed the outcome in 10.1% in the 1996 series.
An unplanned excision leaves microscopic tumour throughout the surgical bed. 35% have residual sarcoma at planned re-excision even when examination and cross-sectional imaging are clear, and this cannot be predicted from size, grade, prior irradiation or the interval since surgery.
The dominant delay is the service delay. Median time from symptom onset to arrival at a specialist centre was 40.4 weeks, of which patient delay was 1.3 weeks and delay in referral was 25.0 weeks (Johnson 2008). Medical professionals, not patients, contribute the greatest source of delay.
Scope of This Page, and What It Deliberately Does Not Do
This is a principles page. It handles the pathway that is identical for every sarcoma - recognition, referral, staging, biopsy discipline, margins, the logic of local control, and surveillance - and hands off to the dedicated pages for the tumour-specific detail.
- Histology-specific content lives elsewhere. For the grading, chemotherapy protocols, histological response assessment and reconstruction detail of individual entities, use the dedicated topics: osteosarcoma, Ewing sarcoma, chondrosarcoma, soft-tissue leiomyosarcoma, and the surface and variant osteosarcoma and chondrosarcoma pages.
- Biopsy technique in full - needle gauge, approach maps by anatomical region, specimen handling and frozen-section policy - is covered in biopsy principles and techniques. This page carries only the decision-level discipline.
- Referral of the soft-tissue lump as a clinic problem is expanded in soft-tissue masses and sarcoma referral, and the imaging vocabulary in MRI of soft-tissue lesions.
- Secondary (metastatic) bone disease is a different problem with a different algorithm - see metastatic bone disease. A destructive bone lesion in a patient over 40 is far more likely to be a metastasis or myeloma than a primary sarcoma, and that possibility must be excluded before a primary-sarcoma pathway is entered. Bone sarcoma guidance is explicit that if a destructive lesion is solitary and no primary site is identified, the patient should be referred to a reference centre rather than biopsied locally.
Sarcomas are rare cancers. The consequence is structural, not merely statistical: no individual non-specialist accumulates enough exposure to calibrate their judgement, so the safety of the pathway is carried by rules and referral thresholds rather than by clinical intuition. Every published framework - the European (ESMO-EURACAN-GENTURIS) guidelines for soft tissue and visceral sarcomas and for bone sarcomas, and the British Sarcoma Group guidelines for soft tissue and for bone sarcomas - reaches the same conclusion by the same route: centralise diagnosis, biopsy and definitive treatment.
Recognition: What Actually Presents
The published rule, verbatim in substance. The British Sarcoma Group guidelines state that any soft-tissue lump exhibiting any of the following four clinical features should be considered malignant until proved otherwise: increasing in size, size greater than 5 cm, deep to the deep fascia, painful. The key recommendation is framed so that pain is not required: any patient with a soft-tissue mass that is increasing in size, has a size greater than 5 cm, or is deep to the deep fascia, whether or not it is painful, should be referred to a diagnostic centre with a suspected soft-tissue sarcoma.
How to use the rule in clinic - the surgeon's lens.
- Measure, do not estimate. Record the maximum diameter in centimetres in the notes at the first visit. "A few centimetres" is not a measurement and will not trigger anything. A 5 cm threshold is meaningless if the size is never written down.
- Determine depth by examination, then confirm it. A lesion that moves freely with the skin and can be lifted away from underlying muscle is superficial; a lesion that becomes fixed and less mobile when the underlying muscle is contracted is at or deep to the fascia. Ask the patient to tense the muscle group while you palpate - a deep mass becomes harder to define and less mobile, a superficial lipoma does not change.
- Believe the history of growth over the examination. Serial enlargement over weeks to months is the single most useful historical feature; a lump the patient says has changed has changed.
- Do not be reassured by absence of pain. Most sarcomas are painless until they are large or compress a nerve. Pain is a fourth feature, not a prerequisite - the recommendation says "whether or not it is painful".
- Do not be reassured by a short history or a remembered injury. Patients commonly attribute a mass to a minor trauma that merely drew attention to it.
- Recurrence after previous "lipoma" excision is a red flag in its own right: a lipoma that recurs is an atypical lipomatous tumour or a well-differentiated liposarcoma until a specialist says otherwise.
Referral: Before the Biopsy, Not After It
The single structural decision that protects the patient is referral before any tissue is taken. Both bone and soft-tissue guidance say this explicitly, and the outcome evidence supports it.
- Soft tissue. Any patient with a suspected soft-tissue sarcoma should be referred to a diagnostic centre and managed by a specialist sarcoma multidisciplinary team, and should undergo triple assessment - clinical history, imaging and biopsy. Excisional biopsy is acceptable only for superficial lesions less than 5 cm in diameter; everything else is imaged and needle-biopsied by the team that may have to resect it.
- Bone. All patients with clinicoradiological findings suggestive of a primary bone tumour should be sent to a bone tumour reference centre prior to biopsy, and referral to the reference centre for initial biopsy is strongly recommended. The biopsy of a suspected primary malignant bone tumour should be carried out at the reference centre by the surgical team who will carry out the definitive resection.
- Why it changes outcome, quantitatively. In the French nationwide NETSARC analysis of 12,528 patients with a first diagnosis of soft-tissue or visceral sarcoma over five years, 5,281 (42.2%) were presented to a specialised multidisciplinary tumour board before treatment and 7,247 (57.8%) only after. Pre-treatment presentation was associated with better compliance with clinical practice guidelines - biopsy before surgery, appropriate imaging, quality of initial surgery, and fewer reoperations (all p less than 0.001) - and with significantly better local relapse-free survival and relapse-free survival in univariate and multivariate analysis. The pre-treatment group had generally worse prognostic characteristics, which strengthens rather than weakens the inference.
When you refer, refer the imaging and the patient, not the specimen. Do not send a patient to a sarcoma service with a healing wound and a histology report - send them with a radiograph, an MRI and intact tissue planes. If a mass has already been excised elsewhere, say so explicitly in the referral: the sarcoma team needs to know that the operative bed, any drain site and any haematoma are potentially contaminated, because that determines the extent of the re-excision, not the size of the original lump.
Margins: The Classical Definitions and the Modern Debate
The Enneking staging paper defines operative margins relative to the lesion, its reactive zone and its anatomic compartment - not as an absolute distance in millimetres. This is the conceptual point examiners probe.
- Plane of dissection
- Through the tumour itself (curettage, debulking, piecemeal removal)
- What is left behind
- Macroscopic tumour
- Typical use
- Benign lesions; planned in selected low-grade intraosseous disease; unacceptable as the intended margin for a high-grade sarcoma
- Plane of dissection
- Through the reactive zone (pseudocapsule) immediately around the tumour - the plane an unplanned 'shelling out' follows
- What is left behind
- Microscopic tumour and satellite nodules within the reactive zone
- Typical use
- Occasionally accepted at a critical neurovascular structure with planned adjuvant radiotherapy
- Plane of dissection
- Through normal tissue outside the reactive zone, removing the tumour with a continuous cuff of normal tissue, within the compartment
- What is left behind
- Potentially skip lesions elsewhere in the compartment
- Typical use
- The standard intended margin for a high-grade sarcoma
- Plane of dissection
- Removal of the entire compartment(s) containing the tumour, from origin to insertion
- What is left behind
- Nothing within the involved compartment
- Typical use
- Rarely performed now; amputation above the involved compartment is the classical example
Two cardinal misconceptions to correct. First, amputation is not automatically a radical margin - an amputation through the involved compartment is a wide, marginal or even intralesional margin depending on where the bone and soft tissues are divided. Second, wide is not a number; a 1 mm cuff of intact fascia can be a more secure barrier than 2 cm of fat, because fascia is a biological barrier and fat is not.
Staging: The Sequence, and What Each Step Changes
Radiograph, MRI, chest CT, then biopsy. The order is deliberate and each step has to change a decision or it should not be done.
- Plain radiographs, two orthogonal views, of the whole bone. First investigation of choice for any bone symptom. Answers aggression (zone of transition, cortical destruction, periosteal reaction, matrix), identifies a pathological fracture, and in cartilage and osteoid lesions is often more diagnostically informative than the MRI that follows. For soft tissue, radiographs identify phleboliths, myositis ossificans and matrix mineralisation that redirect the whole workup.
- MRI of the lesion and the whole compartment, including the joint above and below. Defines intraosseous extent, skip lesions, the soft-tissue component, neurovascular involvement, joint involvement and compartmental status - which is exactly the information the Enneking A/B subdivision and the resection plan require. Whilst the preferred method of imaging is MRI, CT or ultrasound may be appropriate depending on local expertise.
- CT of the chest. The lung is the dominant metastatic site for both bone and soft-tissue sarcomas, and CT remains the diagnostic technique of choice for imaging the chest, appreciating that small nodules are not specific for malignancy. General staging to assess the extent of distant disease should include chest radiography and/or CT.
- Biopsy last, planned against the MRI and against the resection that will follow.
Additional studies, used selectively. Bone scintigraphy or whole-body imaging is used to detect skeletal metastases and multifocal disease; CT is specifically recommended in the pelvis and other flat bones, where the pattern of bone destruction and the presence of matrix mineralisation may be difficult to discern. Bone marrow assessment and systemic staging in Ewing sarcoma follow protocol requirements.
Biopsy Discipline: The Most Examined Principle in Orthopaedic Oncology
The biopsy is the point at which a rare tumour meets a non-specialist, and it is the point at which the largest number of avoidable disasters occur. The Musculoskeletal Tumor Society measured the problem twice, fourteen years apart, and found it essentially unchanged.
1982 (Mankin, Lange, Spanier). Sixteen centres for the treatment of bone and soft-tissue cancer compiled data on 329 biopsies of primary malignant musculoskeletal sarcomas. The investigation showed troubling rates of error in diagnosis and technique, which resulted in complications and adversely affected patient care, and the data were quite different when the biopsy had been carried out in a treatment centre rather than in a referring institution. On that basis the Society made recommendations on biopsy technique and stated that, whenever possible, the procedure should be done in a treatment centre. As restated in the 1996 paper, the 1982 figures were a forced different or more complex operation (or adjunctive irradiation or chemotherapy) in 18%, a change in outcome in 8.5%, and 15 unnecessary amputations.
1996, "revisited" (Mankin, Mankin, Simon). In 1992 the Society repeated the study; 25 surgeons from 21 institutions submitted 597 patients. The results were essentially the same:
- Diagnostic error rate for the total series (referring institutions and treatment centres combined): 17.8%.
- A problem with the biopsy forced the surgeon to carry out a different and often more complex operation, or to use adjunctive irradiation or chemotherapy, in 19.3% (versus 18% previously) - no significant difference.
- A change in the outcome - the need for a more complex resection resulting in disability, loss of function, local recurrence, or death - in 10.1% (versus 8.5% in the 1982 study) - no significant difference.
- Eighteen patients had an unnecessary amputation as a result of the biopsy, compared with fifteen in the previous study.
- Errors, complications and changes in the course and outcome were two to twelve times greater (p less than 0.001) when the biopsy was done in a referring institution instead of in a treatment centre.
The operative rules that follow from those numbers. Each rule exists to protect a specific step of the definitive operation:
- The biopsy belongs to the resecting surgeon. Bone sarcoma guidance states that biopsy of a suspected primary malignant bone tumour should be carried out at the reference centre by the surgical team who will carry out the definitive tumour resection. If that is impossible, it is done in explicit agreement with them.
- Longitudinal incisions only. A longitudinal incision can be excised as an ellipse within the definitive skin flap; a transverse incision cannot, and it crosses compartments.
- One compartment, the shortest route through involved tissue. The tract must not pass through an uninvolved compartment, and must not open a neurovascular plane. Contaminating a second compartment converts an Enneking A lesion into a B for resection purposes.
- The tract must be excisable en bloc. Mark it - tattoo or suture - so the resecting team can find and remove it with the specimen.
- Meticulous haemostasis, and no drain through virgin tissue. A tumour-laden haematoma disseminates cells along fascial planes. If a drain is unavoidable it exits in line with, and immediately adjacent to, the incision so it lies within the future resection field.
- Take enough, and from the right place. Non-representative tissue is a recurring error category; necrotic centre and reactive rim both produce non-diagnostic or misleading results. Image-guided core sampling of the enhancing, viable periphery is the target.
- Send fresh tissue and tell the pathologist what you suspect. Modern sarcoma diagnosis depends on immunohistochemistry and molecular studies (for example, fusion detection in Ewing sarcoma and synovial sarcoma) which require appropriately handled material. Where practicable, reference centres additionally snap-freeze samples for tumour banking with consent.
Excisional biopsy is sanctioned only for superficial lesions less than 5 cm in diameter. For anything deep to the deep fascia, or larger than 5 cm, excision without preoperative imaging and without regard for a margin of normal tissue is the definition of an unplanned excision - the exact exposure studied by Noria and colleagues. It converts a single planned wide excision into a contaminated field requiring a much larger re-excision, and it is the commonest single reason a limb-salvage candidate becomes an amputation candidate.
The Unplanned ('Whoops') Excision: Why a Clear Scan Is Not Clear Tissue
An unplanned excision is defined in the primary study as excisional biopsy or unplanned resection of the lesion without benefit of preoperative imaging and without regard for the necessity to resect the lesion with a margin of normal tissue. It is the surgical analogue of the biopsy errors above, and the data on what is left behind are the most counter-intuitive numbers in orthopaedic oncology.
The Noria study, in its own terms. Sixty-five patients were referred to a university musculoskeletal oncology unit after unplanned excision of an extremity soft-tissue sarcoma elsewhere. Every one of them had positive resection margins histologically on the original specimen, but had no gross evidence of residual tumour on postoperative physical examination and no tumour identified on cross-sectional imaging of the local site - patients with demonstrable residual disease were deliberately excluded. After multidisciplinary consultation, all underwent repeat resection with extensive pathological sampling at mean intervals of 1.2 (standard deviation 0.7) centimetres.
- Gross nodules thought to indicate disease were seen in 27 of 65 (42%), but histology confirmed tumour in only 16 of those 27 (59%) - so the naked eye over-calls.
- Histological sarcoma was found in 7 additional patients in whom no gross nodule was apparent - so the naked eye also under-calls.
- Total residual sarcoma: 23 of 65 (35%).
- Margins of the second resection were positive in 9 of the 23 (39%) who had residual sarcoma.
- Local recurrence occurred in 5 of the 23 (22%), and four of those five had positive margins at repeat resection. That local recurrence rate was significantly higher than in the unit's other extremity soft-tissue sarcoma patients - 16 of 227 (7%), p = 0.03.
- Nothing predicted residual disease: there was no association with initial tumour size or grade, with preoperative irradiation, or with the interval between the unplanned excision and referral.
The clinical conclusion, as the authors state it. Because it is not possible to predict which patients will have residual tumour, it is prudent to advise repeat excision for all patients who have had an unplanned excision of an extremity soft-tissue sarcoma. Unplanned excision complicates decision-making and should be avoided.
Given a patient referred after a whoops excision with a normal post-operative MRI and no palpable mass, the wrong answer is surveillance. A negative examination and a negative scan were the entry criteria to the Noria study, and a third of those patients still had sarcoma in the wound bed. The correct answer is: restage (local MRI and chest CT), refer to the sarcoma multidisciplinary team, plan a wide re-excision of the entire previous surgical bed including scar, drain sites and haematoma cavity, and consider adjuvant radiotherapy in line with the multidisciplinary plan.
Treatment Principles by Tumour Family
You are not expected to run the chemotherapy. You are expected to know which modality carries the local control, which carries the systemic control, and which tumours do not respond to the things people assume they respond to.
Systemic therapy carries the survival; surgery carries the local control - and both are mandatory. Treatment must include complete surgical removal of all detectable tumour sites as well as multiagent chemotherapy. The regimen should include several or all of four drugs: doxorubicin, high-dose methotrexate with folinic-acid (leucovorin) rescue, cisplatin and ifosfamide.
- Preoperative (neoadjuvant) plus postoperative (adjuvant) polychemotherapy is preferred, for two stated reasons: it allows preparation for safe surgery, and it allows preparation of the appropriate prosthesis for the individual patient.
- The definitive surgical procedure is chosen on the anatomical site of the primary, its relationship to neighbouring structures such as vessels and nerves, the age and growth potential of the patient, and probably also the response of the tumour to preoperative chemotherapy.
- Care must be in specialised centres able to provide the full spectrum of care, and, as in other rare malignancies, treatment should be administered within prospective multicentre trials.
- The unsolved problem is explicitly stated in the literature: the dismal prognosis of unresectable or relapsed osteosarcoma.
- Epidemiological texture that changes your index of suspicion: in 3,482 SEER patients, there were large differences in incidence and survival by age, a high proportion of osteosarcoma in Paget disease and as a second or later cancer among the elderly, site differences between age groups, and survival that varied by anatomical site and stage and did not improve significantly from 1984 to 2004.
Full protocol detail, histological response assessment and reconstruction options are in the osteosarcoma topic.
Osteosarcoma - chemosensitive, not radiosensitive: chemotherapy plus complete surgical removal. Ewing sarcoma - chemosensitive AND radiosensitive: polychemotherapy plus surgery and/or radiotherapy. Conventional chondrosarcoma - neither: adequate surgery is the only curative modality. Adult high-grade limb soft-tissue sarcoma - surgery plus radiotherapy; adjuvant chemotherapy not routine.
Surveillance: Long, Chest-Focused, and Still Not Settled by Trial
What the guidelines recommend. For high-grade bone tumours, current protocols recommend follow-up intervals of 2-4 months for the first 3 years after completion of therapy, every 6 months for years 4 and 5, and annually thereafter. For low-grade bone sarcomas, the frequency may be reduced to 4-6 monthly for 2 years and then annually. Local and chest imaging should be the norm, and standard follow-up for all sarcoma cases is currently chest radiograph and clinical review. In soft-tissue sarcoma, regular follow-up is recommended to assess local control and the development of metastatic disease.
Why it does not stop at five years. Late metastases, local recurrences and functional deficits may occur more than 10 years after diagnosis in all tumours, and there is no universally accepted stopping point for tumour surveillance. Endoprosthetic and biological reconstructions also generate their own long-term failure modes - aseptic loosening, infection, implant fracture, leg-length discrepancy in the growing child - so the surveillance clinic is simultaneously an oncological and a reconstructive clinic.
Why you should say "the evidence is lacking" out loud. The bone sarcoma guideline states explicitly that evidence of optimum frequency of follow-up and the best imaging investigations is still lacking. That gap is being addressed prospectively: the Surveillance After Extremity Tumor Surgery (SAFETY) trial is a multicentre 2x2 factorial randomised controlled trial in patients with non-metastatic primary grade II or III soft-tissue sarcoma treated by excision, allocating them to chest radiograph every 3 months, chest radiograph every 6 months, chest CT every 3 months, or chest CT every 6 months for 2 years, with overall survival as the primary outcome of the definitive trial. The pilot's primary outcome was feasibility; secondary outcomes included patient-reported anxiety, satisfaction and quality of life, local recurrence-free and metastasis-free survival, treatment-related complications and net healthcare costs.
"Follow-up is clinical review plus local imaging and chest imaging, at 2-4 monthly intervals for the first three years in high-grade disease, 6-monthly in years four and five, and annually thereafter, extended well beyond ten years because late recurrence and late metastasis occur and there is no universally accepted stopping point. Chest radiograph and clinical review are the current standard, CT is the technique of choice for imaging the chest, and the optimum frequency and modality are the subject of an ongoing randomised trial - so I would follow my unit's protocol and the multidisciplinary team's plan."
Guidelines, Registries & Global Practice
Guidelines converge, and they converge on centralisation. The ESMO-EURACAN-GENTURIS clinical practice guidelines for soft tissue and visceral sarcomas (Gronchi and colleagues, Ann Oncol 2021;32(11): 1348-1365) and the ESMO-EURACAN-GENTURIS-ERN PaedCan guideline for bone sarcomas (Strauss and colleagues, Ann Oncol 2021;32(12):1520-1536) are the principal international documents, produced by multi-national author groups spanning Europe, the United Kingdom, Japan, India, Israel and the Russian Federation - a genuinely international, not regional, consensus. National frameworks such as the British Sarcoma Group guidelines for soft tissue sarcomas (Sarcoma 2010;2010:506182) and for bone sarcomas (Sarcoma 2010;2010:317462) were drawn up from the ESMO and NCCN documents and adapted to local practice, and they state the operational thresholds most usable in clinic - the 5 cm and deep-to-fascia rule, the radiograph-first rule for bone, and the requirement that biopsy of a suspected primary malignant bone tumour is carried out at the reference centre by the team that will perform the definitive resection.
Networks and registries are the delivery mechanism. The French NETSARC network of 26 reference sarcoma centres with mandatory pre-treatment multidisciplinary board presentation and mandatory second pathological review is the clearest demonstration that a system, not just a surgeon, produces the outcome: better guideline compliance and better relapse-free survival in 12,528 patients. Equivalent reference-centre networks operate in the United Kingdom, across the European Reference Networks (EURACAN for adult solid rare cancers, GENTURIS for genetic tumour risk syndromes, ERN PaedCan for paediatric cancer), and in Australia and Japan. National sarcoma registries are used to audit the quality indicators that matter here - unplanned-excision rates, time to specialist review, biopsy-before-surgery rates and diagnostic accuracy.
Where practice diverges worldwide, and what remains constant. Access to MRI, to image-guided biopsy, to molecular pathology, to radiotherapy - and particularly to proton or other charged-particle therapy, which the chondrosarcoma literature identifies as beneficial after incomplete resection - varies enormously between health systems, and endoprosthetic reconstruction is unaffordable in many settings, where biological reconstruction or amputation with prosthetic rehabilitation are the realistic options. What does not vary is the sequence: recognise against explicit thresholds, refer before biopsy, image before biopsy, biopsy on the line of the planned resection, treat within a multidisciplinary team, and follow up long. Every one of those steps is free. The most expensive thing in sarcoma care is an unplanned excision.
Mnemonics & Memory Aids
SARCOMA
Hook:SARCOMA: Size over 5 cm, Any growth, Refer before biopsy, Compartment depth, Order of tests, Margin decides, And follow up long.
BIOPSYThe Six Rules of a Safe Biopsy
Hook:BIOPSY: By the resecting team, In line and longitudinal, One compartment, Plan the tract out, Stop the bleeding, Yield diagnostic tissue.
CRCWhich Sarcoma Responds to What
Hook:Chemo for osteosarcoma, Radio for Ewing, Cut for chondrosarcoma - and for adult high-grade limb soft-tissue sarcoma, cut then irradiate.
MCQ Practice Points
- Soft-tissue referral rule: a lump that is increasing in size, larger than 5 cm, or deep to the deep fascia - whether or not it is painful - should be referred to a diagnostic centre as a suspected soft-tissue sarcoma. Excisional biopsy is acceptable only for superficial lesions less than 5 cm.
- Bone referral rule: pain or a palpable mass arising from any bone warrants investigation; radiograph is the first investigation of choice; night pain is an explicit red flag; patients with clinicoradiological findings suggestive of a primary bone tumour go to a reference centre before biopsy.
- Staging order: radiograph, MRI of the whole compartment with the joint above and below, chest CT, biopsy last. CT is the technique of choice for imaging the chest, with the caveat that small nodules are not specific for malignancy.
- Mankin 1982 (329 biopsies, 16 Musculoskeletal Tumor Society centres): a biopsy problem forced a different or more complex operation in 18%, changed the outcome in 8.5%, and caused 15 unnecessary amputations.
- Mankin 1996 revisited (597 patients, 25 surgeons, 21 institutions): diagnostic error 17.8%, forced operation change 19.3%, outcome change 10.1%, 18 unnecessary amputations, and errors, complications and outcome changes two to twelve times greater at a referring institution (p less than 0.001).
- Noria 1996 (unplanned excision, 65 patients, all with clear examination and clear cross-sectional imaging): residual sarcoma 35% (23/65); gross nodules seen in 42% but confirmed in only 59% of those; not predictable from size, grade, prior irradiation or interval; local recurrence 22% versus 7% (p = 0.03). Re-excise everyone.
- Enneking staging: grade (I low, II high, III any metastasis) x compartment (A intracompartmental, B extracompartmental); margins intralesional, marginal, wide, radical, defined relative to the lesion, its reactive zone and its compartment - not as a fixed distance. Clin Orthop Relat Res 1980;(153):106-120.
- Modern margins (Gundle 2018, 2,217 patients): 10-year local recurrence 8% R0, 21% R1, 44% R2; under R+1mm, R1 rose to 726 cases but recurrence fell to 12% with R0 unchanged at 8%; planned close positive margin at a critical structure 11% versus 8% for R0, p = 0.18, whereas inadvertent positive margin 35% at 10 years.
- Rosenberg 1982 (randomised, 43 patients): limb-sparing plus radiotherapy versus amputation - five-year disease-free survival 71% versus 78% (p = 0.75), overall survival 83% versus 88% (p = 0.99); the only correlate of local recurrence was the final margin, even with postoperative radiotherapy (p less than 0.0001).
- Simon 1986 (227 distal femoral osteosarcomas): no difference in survival or recurrence-free survival between limb salvage, above-knee amputation and hip disarticulation (p = 0.8); 16 of 17 patients with local recurrence died; 18 limb-salvage patients eventually needed amputation; whole-cohort five-year continuously disease-free survival 42%, overall survival 55%.
- Chemosensitivity and radiosensitivity: osteosarcoma chemosensitive; Ewing sarcoma chemosensitive and radiosensitive (survival 70-80% standard-risk localised, ~30% metastatic; CD99, EWSR1-FLI1 in 85%); conventional chondrosarcoma neither (relatively radioresistant, needing greater than 60 Gy after incomplete resection; chemotherapy only possibly effective in mesenchymal and uncertain in dedifferentiated subtypes).
- Adult soft-tissue sarcoma: excision plus postoperative radiotherapy for high-grade limb tumours; adjuvant chemotherapy not routinely recommended; first-line metastatic therapy single-agent doxorubicin, with ifosfamide if anthracyclines are contraindicated.
- Systems of care (Blay 2017, 12,528 patients): pre-treatment specialist multidisciplinary board review in 42.2% improved guideline compliance (biopsy before surgery, imaging, quality of initial surgery, fewer reoperations; all p less than 0.001) and local relapse-free and relapse-free survival.
- Delay (Johnson 2008): median total 40.4 weeks; patient delay 1.3 weeks; service delay 25.0 weeks - the doctor, not the patient, is the bottleneck.
- Atypical presentation (Chotel 2008, 35 children with synovial sarcoma): only half had any of the four recognised clinical features at onset; 48.5% a painless mass; 30.3% no mass at all; 21.2% an unexplained joint contracture; mean symptom duration 98 weeks; diagnosis followed unplanned excision in 15 of 35.
- Surveillance: high-grade bone tumours 2-4 monthly for 3 years, 6-monthly in years 4-5, then annually; low-grade 4-6 monthly for 2 years then annually; late metastases and local recurrence beyond 10 years, with no universally accepted stopping point; optimum frequency and modality remain unproven and are the subject of the randomised SAFETY trial.
Clinical Decision Scenarios
Practise clinical reasoning and management decisions out loud
“A 58-year-old man is referred with a painless lump in the anterior thigh that he first noticed six months ago and thinks has grown. It measures about 8 cm, is firm, and becomes less mobile when he contracts quadriceps. What do you do, and in what order?”
“A 44-year-old woman had a 6 cm 'lipoma' shelled out of her calf at another hospital. Histology shows a high-grade pleomorphic sarcoma with positive margins. She is well, the wound is healed, there is no palpable mass, and an MRI performed since shows no residual tumour. She asks whether she can simply be watched. What do you tell her, and why?”
“Compare the treatment principles for a distal femoral osteosarcoma in a 15-year-old, a pelvic Ewing sarcoma in an 18-year-old, and a grade 2 conventional chondrosarcoma of the proximal femur in a 60-year-old. Where does the cure come from in each?”
Recognise & refer
- Soft-tissue lump: increasing in size OR larger than 5 cm OR deep to the deep fascia - refer, painful or not
- Bone: pain or palpable mass from any bone; radiograph first; NIGHT PAIN is a red flag; reference centre BEFORE biopsy
- Excisional biopsy acceptable only for superficial lesions under 5 cm
- Delay is the doctor's: median service delay 25.0 weeks versus patient delay 1.3 weeks (total 40.4 weeks)
- Atypical: synovial sarcoma in children - 48.5% painless mass, 30.3% no mass, 21.2% unexplained contracture; only half met the four criteria
Stage in this order
- Radiograph (zone of transition, cortical destruction, periosteal reaction, matrix)
- MRI of the whole lesion and compartment including the joint above and below (skip lesions, neurovascular, joint)
- Chest CT - lung is the dominant metastatic site; CT is the technique of choice; small nodules are NOT specific
- Biopsy LAST, planned against the MRI
- CT is specifically recommended in the pelvis and other flat bones
Biopsy numbers (quote exactly)
- 1982: 329 biopsies, 16 MSTS centres - 18% forced a different/more complex operation, 8.5% outcome change, 15 unnecessary amputations
- 1996 revisited: 597 patients, 25 surgeons, 21 institutions - diagnostic error 17.8%, operation change 19.3%, outcome change 10.1%, 18 unnecessary amputations
- Errors, complications and outcome changes 2-12x greater at a referring institution than a treatment centre (p less than 0.001)
- Rules: resecting team, longitudinal, one compartment, excisable marked tract, haemostasis, drain in line, sample viable periphery
Whoops excision
- Definition: excision without preoperative imaging and without regard for a margin of normal tissue
- Noria 1996: residual sarcoma 23/65 (35%) despite clear examination AND clear cross-sectional imaging
- Gross nodules seen 42%, histologically confirmed in only 59% of those; 7 more had tumour with no visible nodule
- Local recurrence 5/23 (22%) versus 16/227 (7%), p = 0.03; NOT predictable from size, grade, radiotherapy or interval
- Action: restage, MDT, central pathology review, wide re-excision of the whole bed including scar, drain sites and haematoma - never observe
Staging systems & margins
- Enneking: I low grade, II high grade, III metastases present; A intracompartmental, B extracompartmental (Clin Orthop Relat Res 1980;(153):106-120)
- Margins: intralesional, marginal, wide, radical - defined relative to the lesion, its reactive zone and its compartment
- AJCC/UICC TNM: histological grade plus size, nodes, metastasis; no margin definition
- Modern R classification (Gundle 2018, n = 2,217): 10-year local recurrence 8% R0, 21% R1, 44% R2
- R+1mm: R1 cases 726 versus 278 but recurrence only 12%, R0 unchanged 8% - a negative but sub-millimetre margin may suffice with multidisciplinary treatment
- Planned close positive margin at a critical structure 11% versus R0 8% (p = 0.18); INADVERTENT positive margin 35% at 10 years
- Amputation is not automatically a radical margin
Treatment by family
- Osteosarcoma: doxorubicin + high-dose methotrexate with folinic-acid rescue + cisplatin +/- ifosfamide, neoadjuvant and adjuvant, plus complete surgical removal of all detectable disease
- Ewing sarcoma: chemosensitive AND radiosensitive - surgery, radiotherapy and polychemotherapy; 70-80% standard-risk localised, ~30% metastatic; CD99, EWSR1-FLI1 in 85%
- Conventional chondrosarcoma: SURGERY - relatively radioresistant (above 60 Gy after incomplete resection; protons beneficial); chemotherapy only possibly effective in mesenchymal, uncertain in dedifferentiated
- Chondrosarcoma by grade: wide en-bloc for intermediate/high; extensive intralesional curettage + local adjuvant + graft for low grade confined to bone
- Adult high-grade limb STS: excision plus postoperative radiotherapy; adjuvant chemotherapy NOT routine; first-line metastatic single-agent doxorubicin (ifosfamide if anthracyclines contraindicated)
Limb salvage vs amputation
- Rosenberg 1982 (randomised, n = 43): 5-year DFS 71% vs 78% (p = 0.75), OS 83% vs 88% (p = 0.99); only correlate of local recurrence was the FINAL MARGIN (p less than 0.0001), even with radiotherapy
- Simon 1986 (n = 227, distal femur osteosarcoma): no difference between salvage, above-knee amputation and hip disarticulation (p = 0.8); 16 of 17 with local recurrence died; 18 salvage patients later needed amputation; cohort 5-year CDFS 42%, OS 55%
- Amputation is correct when a wide margin cannot be achieved with a functional limb; isolated limb perfusion may salvage some otherwise-amputation cases
Systems & surveillance
- Blay 2017 (NETSARC, n = 12,528): pre-treatment specialist MDT board improved guideline compliance and relapse-free survival despite worse baseline prognosis
- High-grade bone tumours: 2-4 monthly for 3 years, 6-monthly years 4-5, then annually; low grade 4-6 monthly for 2 years then annually
- Local AND chest imaging; chest radiograph plus clinical review is current standard; CT is the technique of choice for the chest
- Late metastases and local recurrence beyond 10 years - NO universally accepted stopping point
- Optimum frequency and modality remain unproven - randomised SAFETY trial (2x2: CXR vs chest CT, 3- vs 6-monthly)
Limb Salvage versus Amputation: What the Evidence Does and Does Not Say
Limb salvage is the default, but the evidence supports it for a specific reason that candidates frequently misstate: not because salvage is oncologically superior, but because it is oncologically equivalent when the margin is equivalent.
The randomised evidence (soft-tissue sarcoma). Between May 1975 and April 1981, 43 adults with high-grade extremity soft-tissue sarcoma were prospectively randomised (2:1) to limb-sparing resection plus adjuvant radiotherapy (27 patients) or amputation at or above the joint proximal to the tumour including all involved muscle groups (16 patients). The limb-sparing group had wide local excision followed by 5,000 rads to the whole anatomical area at risk and 6,000-7,000 rads to the tumour bed; both groups received postoperative doxorubicin, cyclophosphamide and high-dose methotrexate.
- Local recurrence: four in the limb-sparing group, none after amputation (p = 0.06).
- Five-year disease-free survival: 71% versus 78%, p = 0.75 - no difference.
- Five-year overall survival: 83% versus 88%, p = 0.99 - no difference.
- The only correlate of local recurrence on multivariate analysis was the final margin of resection; positive margins carried a higher likelihood of local recurrence than negative margins (p less than 0.0001) even when postoperative radiotherapy was used.
- The same report included a parallel randomised study of postoperative chemotherapy in 65 patients with high-grade extremity soft-tissue sarcoma, showing a marked advantage for chemotherapy in three-year continuous disease-free survival (92% versus 60%, p = 0.0008) and overall survival (95% versus 74%, p = 0.04).
The multi-institutional evidence (bone sarcoma). A retrospective multi-institutional study of 227 patients with osteosarcoma of the distal femur compared three cohorts - limb-sparing procedure (73), above-knee amputation (115), and hip disarticulation (39):
- Local recurrence: 8 of 73 after limb salvage, 9 of 115 after above-knee amputation, 0 of 39 after hip disarticulation.
- Metastasis: 43 of 73, 65 of 115, and 21 of 39 respectively. Death: 33 of 73, 48 of 115, and 18 of 39.
- Of the 17 patients who had a local recurrence, 16 died - local recurrence in this disease is a marker of biological aggressiveness, not merely a technical failure.
- In the limb-salvage group, 18 patients ultimately required amputation - 8 for local recurrence and 10 for other local complications. This is the honest counterweight: salvage carries a reoperation and failure burden that amputation does not.
- Kaplan-Meier estimates of survival and of freedom from recurrent disease showed no difference among the three surgical groups (Mantel-Cox p = 0.8) at a median follow-up of five and a half years, and covariate-adjusted estimates were similar. For the whole cohort, continuously disease-free survival was 42% and overall survival 55% at five years.
Amputation remains correct when a wide margin cannot be achieved with a functional limb - major neurovascular encasement that cannot be reconstructed, extensive contamination from an unplanned procedure or a pathological fracture, tumour fungation or infection, failed reconstruction with uncontrolled local disease, or a reconstruction whose expected function is worse than a well-fitted prosthesis. Soft-tissue sarcoma guidance states plainly that occasionally amputation remains the only option, and that isolated limb perfusion may permit limb salvage in some cases where amputation is the only other option. Framing amputation as failure is a disservice: the operation that reliably achieves the margin is the operation that treats the cancer.
Evidence & Key Studies
The hazards of biopsy in patients with malignant primary bone and soft-tissue tumors
- Members of the Musculoskeletal Tumor Society, representing sixteen centres for the treatment of bone and soft-tissue cancer, compiled data on 329 biopsies of primary malignant musculoskeletal sarcomas.
- The investigation showed troubling rates of error in diagnosis and in technique, which resulted in complications and adversely affected the care of patients.
- The data were quite different when the biopsy had been carried out in a treatment centre rather than in a referring institution.
- As restated in the 1996 follow-up paper, the 1982 figures were: a biopsy problem forced a different or more complex operation (or adjunctive irradiation or chemotherapy) in 18%; the outcome changed in 8.5%; and 15 patients had an unnecessary amputation.
- On the basis of these observations the Society issued recommendations on the technical aspects of biopsy and stated that, whenever possible, the procedure should be done in a treatment centre rather than in a referring institution.
The hazards of the biopsy, revisited. Members of the Musculoskeletal Tumor Society
- Twenty-five surgeons from twenty-one institutions submitted 597 patients; the results were essentially the same as in the 1982 study.
- The rate of diagnostic error for the total series (referring institutions and treatment centres combined) was 17.8%.
- A problem with the biopsy forced the surgeon to carry out a different and often more complex operation, or to use adjunctive irradiation or chemotherapy, in 19.3% (compared with 18% in the previous study) - no significant difference.
- A change in outcome - a more complex resection resulting in disability, loss of function, local recurrence or death - occurred in 10.1% (compared with 8.5% in 1982) - no significant difference.
- Eighteen patients had an unnecessary amputation as a result of the biopsy, compared with fifteen previously.
- Errors, complications and changes in the course and outcome were two to twelve times greater (p less than 0.001) when the biopsy was done in a referring institution instead of a treatment centre.
Residual disease following unplanned excision of soft-tissue sarcoma of an extremity
- Sixty-five patients referred after unplanned excision elsewhere; all had positive resection margins histologically, but no gross residual on examination and no tumour on cross-sectional imaging - patients with demonstrable residual disease were excluded.
- Extensive pathological sampling of the re-excision specimen at mean intervals of 1.2 (SD 0.7) cm: gross nodules were seen in 27 (42%) but histology confirmed tumour in only 16 (59%) of those.
- Sarcoma was found in 7 additional patients with no gross nodule, giving residual sarcoma in 23 of 65 (35%).
- Margins of the second resection were positive in 9 of the 23 (39%) with residual sarcoma; 5 of the 23 (22%) developed local recurrence, four of whom had positive re-excision margins.
- That local recurrence rate was significantly higher than in the unit's other extremity soft-tissue sarcoma patients - 16 of 227 (7%), p = 0.03.
- No association between residual disease and initial size, grade, preoperative irradiation, or interval from unplanned excision to referral - residual tumour is not predictable.
References
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