Soft Tissue Sarcoma Knowledge Centre
Diagnosis
Staging and Risk Assessment
Staging
Some of the information within this section is taken from the ESMO clinical guidelines and its use is subject to permission from ESMO.
Several staging systems [e.g. the American Joint Committee on Cancer (AJCC) and International Union against Cancer (UICC) staging systems] have been devised for STS to help determine the prognosis for individual patients. The stage of disease is determined based on the histopathological grade, and depth and size of the tumour (Table 2). Stage I tumours are low grade (i.e. not aggressive), small and superficial or deep but with no metastases; patients with stage I disease have a good prognosis – 5-year survival rates are approximately 90%1. In contrast, high grade, deep and/or bulky tumours are associated with a 5-year survival of only 10–20%1.
| Stage | Definition | |
|---|---|---|
| Stage I | Low-grade, superficial |
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| Stage II | High-grade, superficial |
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| Stage III | High-grade, large |
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| Stage IV | Anymetastases to lymph |
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American Joint Committee on Cancer 2002
Risk Assessment
The pathology report should include an appropriate description of tumor margins (i.e. the status of inked margins and the distance between tumor edge and the closest inked margins). This allows the assessment of marginal status (i.e. whether the minimum margin is intralesional, marginal, wide, and which are their distances from surrounding tissues). The pathologic assessment of margins should be made in collaboration with the surgeon. The surgical report should provide details on the surgical conduct with regard to possible contaminations (i.e. it should mention whether the tumor was opened, etc.).
If preoperative treatment was carried out, the pathology report should include a tumor response assessment. In contrast to osteosarcoma and Ewing's family of tumors, however, no validated system is available at present in this regard, and no percentage of residual 'viable cells' is considered to have a specific prognostic significance. This depends on some difficulties, including the presence of non-treatment-related necrosis and hemorrhage and the heterogeneity of post-treatment changes. A multidisciplinary judgment is recommended, involving the pathologist and the radiologist.
A chest CT scan is mandatory for staging purposes. Depending on the histological type and other clinical features, further staging assessments may be recommended (e.g. regional lymph node assessment for synovial sarcoma or epithelioid sarcoma, abdominal CT scan for myxoid liposarcoma, etc.).
The AJCC/UICC staging classification system stresses the importance of the malignancy grade in sarcoma. However, its use in routine practice is limited. In addition to grading, other prognostic factors are tumor size and tumor depth.
Reference:
1. Stojadinovic A, Leung DH et al. (2002) "Primary adult soft tissue sarcoma: time-dependent influence of prognostic variables." J Clin Oncol 20(21): 4344–52.