Relationship between doxorubicin binding ability and tumor volume decrease after chemotherapy in adult malignant soft tissue tumors in the extremities.

We have previously reported that the doxorubicin (DOX) binding ability detected by the DOX (or adriamycin) binding assay closely correlated with the chemosensitivity of human osteosarcomas (1). We performed the present study to clarify the relationship between the DOX binding ability (%DB) and the histologic response, rate of decrease in tumor volume of malignant soft tissue tumors after preoperative chemotherapy and prognosis. Nine malignant soft tissue tumors (4 liposarcomas, 3 synovial sarcomas, one malignant fibrous histiocytoma (MFH) and one extraskeletal osteosarcoma (EOS)) which arose at the extremities of adult patients were analyzed by the DOX binding assay using freshly biopsied specimens. After preoperative chemotherapy including DOX or pirarubicin (THP), the rate of decrease in tumor volume was measured using magnetic resonance imaging, and the histologic response expressed as tumor necrosis to chemotherapy was also investigated. All the patients, apart for one, were continuously disease-free after treatment. One patient with EOS died of metastatic disease before surgery. The histologic response in 8 tumors without EOS was poor. The %DB of 5 tumors was greater than 80% (average: 95.90%), whereas that of 4 tumors was less than 80% (average: 38.33%). Although there was no correlation between the %DB and the histologic response, or prognosis, a significantly positive correlation was found between the %DB and the rate of decrease in tumor volume (r = 0.7455, p < 0.05). These results suggest that in malignant soft tissue tumors, the rate of decrease in tumor volume after chemotherapy might be a better indicator for chemosensitivity than the histologic response and also that the DOX binding ability might be a good predictor for chemosensitivity before chemotherapy.