Therapy-induced tumor regression in adult soft tissue sarcomas-morphological findings

Abstract

Morphological findings of 21 soft tissue sarcomas of adulthood following preoperative chemo- and/or radiotherapy including perfusion therapy and resection are presented. The therapy-induced changes included a spectrum ranging from total tumor regression up to still completely vital tumor (median of all cases: 30% vital tumor tissue). 7 of 21 sarcomas (33%) were evaluated as responders (grade I-III). So-called malignant fibrous histiocytoma (MFH) revealed a good tumor response to preoperatively administered therapy (regression grades I and II). Myxoid/round-cell liposarcoma exhibited regression grades of IV-V (i.e. 30% up to 95% vital tumor tissue, non-responders). Synovial sarcoma was characterized by regression grades III up to VI (i.e. up to 100% vital tumor tissue without any signs of regression, 83% non-responders). Completely vital tumor was evident in 2 synovial sarcomas despite preoperative tumor therapy. These findings hint towards differences in response of distinct sarcoma entities to preoperative chemo-/radiotherapy. A grading of therapy-induced tumor regression in adult soft tissue sarcomas may best refer to already established grading schemes (e.g. according to the grading scheme for osteosarcomas following chemotherapy of Salzer-Kuntschik). A report of sarcoma resection specimens should include the percentage of vital tumor tissue.