Histoculture drug response assay predicts the postoperative prognosis of patients with esophageal cancer

Predicting response to chemotherapy would provide patients suffering from malignant tumor with not only more favorable outcomes, but also reduction of adverse events, and would enable chemotherapy tailored to individual patients. The purpose of this retrospective study was to evaluate the utility of histoculture drug response assay (HDRA) with the MTT endpoint. Subjects comprised 53 consecutive patients diagnosed with esophageal cancer, with 15 patients receiving preoperative chemoradiotherapy (CRT) followed by surgery (CRT group; n=15) and 38 patients undergoing surgery (surgery group; n=38), including 17 patients with histological lymph node metastasis who received postoperative chemotherapy. Tumor samples obtained from patients were used for HDRA with MTT endpoint and correlations of sensitivity from HDRA with MTT endpoint to clinical response to preoperative CRT, accuracy of in vitro sensitivity test, and clinical outcomes based on HDRA sensitivity were analyzed. HDRA was able to evaluate 379 of 424 assays (89.3%). In the CRT group, no significant correlation was confirmed between efficacy rate of 5-fluorouracil or cisplatin and histological findings in resected specimens after CRT. Efficacy rates of several anticancer agents using HDRA in the surgery group were observed in the range of 0.0-44.8%. On examination of clinical outcomes in the surgery group, in which patients with stage III received adjuvant chemotherapy, chemosensitivity-negative patients tended to display worse prognosis than chemosensitivity-positive patients. HDRA with MTT endpoint probably predicts the postoperative prognosis of patients with esophageal cancer.