[Subrenal capsule assay--an experimental study and clinical application to chemosensitivity tests]

We have attempted to investigate the usefulness of the subrenal capsule assay (SRCA). Initially, we compared the results of antitumor activities of 27 anticancer drugs obtained using the SRCA in BDF1 mice and the subcutaneous transplantation assay in nude mice, and it became clear that these results correlated well. It was thus apparent that the antitumor activity of drugs could be evaluated faster, more cheaply and more easily using the SRCA. In the SRCA, the overall success rate for growing tumors (with a tumor growth rate of more than 1.0) from patients was 79% (106/134) and the success rates for each tumor type were as follows: malignant lymphoma 90%, ovarian cancer 87%, sarcoma 77%, breast cancer 76%, colorectal cancer 73% and renal cancer 58%. In a retrospective analysis of correlation between the antitumor activities assayed by the SRCA and the respective clinical responses, 11 out of 25 trials were true positive (79%) and 7 trials were true negative (64%). The sensitivity and specificity levels of this test were 73% and 70%, respectively. The tumor growth inhibition rates were correlated well with the clinical responses. The advantages of the SRCA are: it has a high success rate; it allows rapid evaluation; it can be applied for masked compounds; and it has a good clinical correlation. These advantages indicate that the SRCA is of potential value as a predictive test for selection of anticancer drugs on an individual patient basis.