Tumor vascularization and histopathologic regression of soft tissue sarcomas treated with isolated limb perfusion with TNF-α and melphalan.

Background: Isolated limb perfusion (TM-ILP) achieves high response rates in soft tissue sarcomas (STS). Some tumors show an insufficient association between radiological and pathological response. We investigated STS after TM-ILP with a primary emphasis on histologic regression patterns.

Methods: In 53 patients with STS, TM-ILP with subsequent tumor resection was performed. Regression was assessed by the Salzer-Kuntschik regression scale. Microvessel density (MVD) of primary biopsies of 37 patients was determined by immunohistochemistry. Tumor regression was correlated with MVD of primary biopsies and other clinico-pathological parameters.

Results: Regression presented mainly as necrosis or fibrosis/sclerosis upon histopathology. MFH, leiomyosarcoma, or clear cell sarcoma (CCS) responded well; whereas liposarcomas, synovial sarcomas, or MPNST were poor responders. MFH often had abundant necrosis; while other STS mainly presented with fibrosis/sclerosis. MVD had no influence on regression grade but modulated histologic regression patterns. Excellent regression demonstrated a trend toward an association with improved survival and local control.

Conclusion: TM-ILP yielded high response rates in STS. Regression after TM-ILP exhibits MVD-dependent histopathologic patterns and variable efficacy in different sarcoma types. Complete regression seems to be a favorable prognostic factor. A concerted consideration of histopathology and clinical findings may contribute to a better clinical assessment of regression after TM-ILP.