Correlation of an in vitro chemosensitivity test using [3H] incorporation with the response in case of human tumor chemotherapy.

We developed a method for performing in vitro drug testing using [3H] incorporation into a primary human tumor. The test was applied to specimens from 60 patients with advanced malignancies, mainly gastrointestinal cancers. Forty-six specimens had sufficient growth for the drug testing. Forty-seven per cent of the gastric cancer specimens and 67 per cent of those from patients with colorectal cancer demonstrated an in vitro chemosensitivity. Among 9 chemotherapeutic drugs tested, ara-C, 5-fluorouracil, and mitomycin C showed the high percentages of positive sensitivity for gastric cancer, whereas actinomycin D, carboquone, and nimustine hydrochloride were sensitive in case of colorectal cancer. Clinical responses were compared with the results of the test. In 46 drug assays, in vitro/in vivo drug responses correlated in 78 per cent, with a true-positive rate of 47 per cent and a true-negative rate of 94 per cent. This test appears to be a reliable indicator for the clinical response to the same chemotherapeutic drugs in cases of the malignant diseases seen clinically.