Clinical applicability of the ATP cell viability assay as a predictor of chemoresponse in platinum-resistant epithelial ovarian cancer using nonsurgical tumor cell samples

Objectives. There is no basis for choosing one chemotherapy over another in platinum-resistant epithelial ovarian cancer based on published response r ates. This study explores the feasibility and accuracy of the ATP cell viab ility assay (ATP-CVA) in predicting chemoresponse in these difficult situat ions to choose the most appropriate drug for treatment. Methods. Predominantly nonsurgical tumor samples for histological proof of recurrence were tested against a panel of drugs for salvage chemotherapy, C linicians were blinded to the test results. Patient responses were evaluate d after a minimum of three cycles of single-agent chemotherapy and correlat ed with test results. Results. The evaluability rate was 85% (5 of 33 contaminated), The majority (24) were obtained by abdominal paracentesis and trucut biopsy. Of the 28 successful assays, 8 were excluded from analysis because four chose not to have chemotherapy and four withdrew after fewer than three cycles because o f unacceptable side effects. The overall response rate to salvage chemother apy was 15%. The sensitivity was 100% and specificity 82%, Resistance was c orrectly predicted in 100% and response correctly predicted in 50%. The out comes of 17 of 20 patients were predicted correctly, giving an accuracy of 85%. Conclusions. It is feasible to test nonsurgical tumor specimens in recurren t cancer. The ATP-CVA correctly identified a group of patients with a 50% c hance of response to salvage chemotherapy. This information may be useful i n the decision-making process. A prospective, randomized study will be done to confirm these results. (C) 2000 Academic Press.