In vitro chemosensitivity test to predict chemosensitivity for paclitaxel, using human gastric carcinoma tissues

Therapy guided by chemotherapy sensitivity and resistance assays may lead to rational treatment decisions. Paclitaxel, one of several new drugs for gastric carcinoma, has not been extensively evaluated by in vitro chemosensitivity tests.

Chemosensitivity testing by histoculture drug response assay (HDRA) was performed with fresh specimens of primary tumor from 113 patients with gastric carcinoma. The test was performed in medium containing paclitaxel at three different concentrations for the initial 45 samples. Correlations between the results of chemosensitivity testing, determined at the optimal concentration, and the patients' clinicopathologic factors and outcome were then assessed for all patients.

By analyzing the initial 45 samples, 10 microg/ml was considered the optimal concentration of paclitaxel for this test. HDRA was successfully performed for 100 of 113 samples and chemosensitivity, calculated as the percentage of optical density of a tumor treated with anticancer drugs in relation to the optical density of the tumor cultured in the medium only, was distributed widely at this concentration. No significant correlation was observed between chemosensitivity and age, sex, clinical stage, histopathologic type, and outcome of patients with gastric carcinoma.

A histoculture drug response assay can now be performed to predict the chemosensitivity of paclitaxel at the concentration found in the current study. The accuracy of the assay to actually predict survival needs to be validated by a prospective clinical trial involving patients who have received paclitaxel in the postoperative adjuvant setting.