[Clinical studies on a rapid screening assay for anticancer agents with nude mice and isotopic evaluation].

A rapid method using nude mice has been established as an in vivo model for assessing the chemosensitivity of individual human tumors, in which the final evaluation is made with 3H-thymidine (3H-TdR) incorporation into the treated tumor. In 234 of 289 cancers, the chemosensitivity of anticancer agents was evaluated by this method. This assay proved to be feasible in a sufficiently high percentage of human primary tumors (81.0%). The rate of positive sensitivity against all tumors was 23.8% for MMC, 12.3% for 5-FU, 29.1% for CPM and 23.5% for ADM, respectively. The sensitivity of anticancer agents varied according to the type of cancer. Correlation between the sensitivity test and the end results after chemotherapy in cases of inoperable gastrointestinal cancers was investigated, prospectively. Out of 19 cases, the 50% survival time of 11 patients treated with sensitive agents was longer than that of 8 patients treated with insensitive agents. From a prospective-correlative study carried out on 25 patients, this assay appeared to be correlated with clinical response (overall agreement, 76.0%) with specific agreements of sensitivity and resistance of 37.5% and 94.1%, respectively. From these results, it seems reasonable to conclude that this sensitivity test using a human/nude mouse system is a useful screening assay for revealing appropriate agents for the treatment of patients with cancer.