[Clinical application of chemosensitivity testing using radioactive precursors]

In vitro drug testing using (3H) incorporation was utilized for specimens from 60 patients with advanced malignancies, mainly gastrointestinal cancers. Forty-six specimens had sufficient growth for drug testing. Forty-seven percent of stomach cancer specimens and 67% of colorectal cancer specimens demonstrated in vitro chemosensitivity. Among 9 chemotherapeutic agents tested, ara-C, 5-fluorouracil, and mitomycin C had higher percentages of positive sensitivity for stomach cancer, whereas actinomycin D, carboquone, and ACNU had a more pronounced effect on colorectal cancer. A comparison was made between the results of chemosensitivity tests and clinical response. In 46 drug assays, in vitro/in vivo drug responses were correlated in 78% with a true-positive predictive rate of 47% and a true-negative rate of 94%. This test appears to be a reliable indicator for clinical response to the same chemotherapeutic agents in human malignant disease.