The pathologic response of resected synovial sarcomas to hyperthermic isolated limb perfusion with melphalan and TNF-α: a comparison with the whole group of resected soft tissue sarcomas

BACKGROUND: Hyperthermic isolated limb perfusion with tumor necrosis factor-α and melphalan (TM-HILP) has been successfully used to treat limb soft tissue sarcomas (STSs) with high response rates. The data on the effectiveness of HILP-TM for the treatment of STSs are mainly based on various STS types. The aim of this study was to investigate the responses of synovial sarcomas (SS) to TM-HILP. METHODS: A total of 125 TM-HILP-treated tumors (STS(all)), including 14 SSs, were included in the study. The tumors were subdivided into proximal and distal limb localizations. Tumor typing (using the WHO classification), resection status (using the UICC classification), and response to therapy were assessed using light microscopy. The SSs were tested for the SYT-SSX translocation using RT-PCR. The following tests were applied: a chi-squared test, a t test, and the Mann-Whitney U test. RESULTS: The SSs were localized distally more often than were the STS cohort (STS(−SS)) (85.7% vs. 32.4%) and were smaller (5.8 cm vs. 10.7 cm). There were no differences in the responder/nonresponder ratios or the mean percentages of pathological regression between the SS and STS(−SS) cohorts (74.0% vs. 76.0%). A general localization-dependent difference in the tumor responses to TM-HILP could not be detected in the STS(all) cohort (distal, 72.0% vs. proximal, 78.0%); however, a UICC R0 status was more often observed in proximal tumors (distal, 50.0% vs. proximal, 71.4%). There was no association between the SYT-SSX type and SS responses to TM-HILP. CONCLUSIONS: Because of the high response rates, TM-HILP is recommended for the treatment of SSs. The distal limb localization of TM-HILP-treated STSs was generally (STS(all) cohort) associated with fewer R0 resections.