Clinical Applicability of the ATP Cell Viability Assay as a Predictor of Chemoresponse in Platinum-Resistant Epithelial Ovarian Cancer Using Nonsurgical Tumor Cell Samples

Abstract

Objectives. There is no basis for choosing one chemotherapy over another in platinum-resistant epithelial ovarian cancer based on published response rates. This study explores the feasibility and accuracy of the ATP cell viability assay (ATP-CVA) in predicting chemoresponse in these difficult situations 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. Clinicians were blinded to the test results. Patient responses were evaluated after a minimum of three cycles of single-agent chemotherapy and correlated 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 of unacceptable side effects. The overall response rate to salvage chemotherapy was 15%. The sensitivity was 100% and specificity 82%. Resistance was correctly predicted in 100% and response correctly predicted in 50%. The outcomes of 17 of 20 patients were predicted correctly, giving an accuracy of 85%.Conclusions. It is feasible to test nonsurgical tumor specimens in recurrent cancer. The ATP-CVA correctly identified a group of patients with a 50% chance of response to salvage chemotherapy. This information may be useful in the decision-making process. A prospective, randomized study will be done to confirm these results.