What is the prognosis of soft-tissue tumors?

Updated: Dec 03, 2018
  • Author: Vinod B Shidham, MD, FRCPath; Chief Editor: Omohodion (Odion) Binitie, MD  more...
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Answer

Outcome and prognosis depend on several, often interrelated factors, including the following:

  • Tumor size
  • Depth of tumor
  • Histologic type
  • Adequacy of surgical margins
  • Histologic grade
  • Clinical stage
  • DNA ploidy
  • Cell proliferation
  • Oncogene mutations

As with tumors of other tissues, a direct relation exists between the size of soft-tissue sarcomas and outcome. The larger tumors confer a worse prognosis. [6]

Superficially located tumors (dermis and subcutaneous tissue) have a relatively better prognosis than do deep-seated lesions (intermuscular/intramuscular, retroperitoneal) of similar histologic type. [7, 8]  This difference probably results from the fact that superficial lesions are considerably smaller at the time of excision.

With few exceptions, most sarcomas of the same stage and grade behave the same regardless of histologic subtype. Some soft-tissue tumors (eg, atypical lipomatous tumors) are low-grade, without any ability to metastasize. Others, such as pleomorphic liposarcoma, are highly aggressive, with a tendency for distant metastases.

Adequacy of surgical margins is directly related to local relapse. [9, 10, 8, 11, 6]  However, development of distant metastases may not be related to the development of local recurrence. [12]

A relation exists between various microscopic histologic grading systems and outcome. [7, 6]

Clinical stage is the most important predictor of clinical outcome. Clinical staging is done in accordance with the grade-tumor-node-metastasis (GTNM) system, which incorporates microscopic grading (see Histologic Findings).

DNA ploidy can be evaluated by flow-cytometric studies performed on formalin-fixed, paraffin-embedded tissue sections or by image analysis using cytology smears. Aneuploidy is observed in tumors that have a higher microscopic grade and a greater rate of cell proliferation. However, its role as an independent prognostic factor has not been established. [13]

The number of mitotic figures stratifies the tumors into benign, intermediate, and malignant categories and is incorporated into most grading systems. Cell proliferation markers, including Ki-67 and p105, are useful for evaluation of proliferative activity and its relation to prognosis. [14, 15, 16]  Like DNA ploidy, however, proliferation markers remain to be established as independent prognostic factors.

Oncogene mutations (eg, mutations of TP53, overexpression of MDM2, and altered expression of the retinoblastoma gene) have reportedly been associated with a worse prognosis. [17, 18, 19]


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