Heterogeneity of Adenosine Triphosphate-Based Chemotherapy Response Assay in Colorectal Cancer - Secondary Publication

PURPOSE: Adenosine triphosphate-based chemotherapy response assay (ATP-CRA) is a well-documented and validated technology that can individualize chemotherapy for patients with lung, stomach, or breast cancer. This study explored the feasibility of ATP-CRA as a chemosensitivity test in patients with colorectal cancer. MATERIALS AND METHODS: A total of 118 patients who underwent surgical resection for colorectal adenocarcinoma were analyzed for chemosensitivity to 6 anticancer drugs using ATP-CRA. We calculated the cell death rate (CDR) by measuring intracellular ATP levels of drug-exposed cells and untreated controls. RESULTS: Interpretable results were available for 85.5% (118/138) of patients. The mean coefficient of variation for triplicate ATP measurements was 9.2%. The highest CDR was observed in irinotecan (34.0%) and the lowest CDR in etoposide (21.0%). Paclitaxel had the broadest range of CDR (0-86.7%) and 5-FU had the narrowest range of CDR (0-56.8%). The overall highest responsiveness was seen most prevalently in irinotecan (24.7%, 23/93 patients). Irinotecan had the greatest responsiveness in patients with well differentiated and moderately differentiated carcinoma. CONCLUSION: Our study suggests that ATP-CRA could be used to identify patients with colorectal cancer who might benefit from treatment with a specific chemotherapeutic agent.