In vitro chemosensitivity of human soft tissue sarcoma

Chemotherapy is essential in the treatment of small round cell sarcomas. However, as yet there is no progress concerning the efficacy of chemotherapy in the treatment of other types of soft tissue tumors (STS). The Histoculture Drug Response Assay (HDRA) is an in vitro chemosensitivity test that has a high correlation with clinical response, the usefulness of which has been reported in various kinds of solid tumors. However, there has never been a report on its use in STS until now. In this study, in order to investigate the variation in chemosensitivity in STS, fresh biopsy or surgical samples of STS were tested using the HDRA method. Drug sensitivity testing by HDRA showed that two drugs, ADM and THP, had a significantly higher inhibitory rate than CDDP, IFOS, or VP-16 in the thirty-three soft tissue sarcomas tested. Depending on the morphological type, spindle cell sarcomas were sensitive to THP, which showed significantly higher inhibition rates than CDDP, IFOS, or VP-16. Small round cell sarcomas were relatively sensitive to all of the drugs tested. However the drug sensitivity of pleomorphic cell sarcoma was low except for ADM and THP, while its sensitivity to THP was higher than about 70%. However, there are numerous other soft tissue sarcomas that do not belong to these categories; drug sensitivity testing in each of them and the devising of individualized treatment strategies seems necessary to improve the therapeutic outcome.