Comparison between macroscopic and microscopic evaluation of tumour responsiveness using the subrenal capsule assay.

Using the subrenal capsule assay in normal mice, a histologic evaluation was made of 8 human primary ovarian tumours and 3 human colon, 2 lung and 5 ovarian carcinomas growing in serial passage in nude mice. The results of the evaluation indicated that there is a tumour- and drug-dependent correlation between the macroscopically and microscopically evaluated effects, with cyclophosphamide demonstrating excellent concordance but adriamycin and cisplatin both demonstrating consistently more tumour cell killing on histologic analysis than could be appreciated macroscopically. Leukocyte infiltration and fibrosis were greatly increased by the latter 2 drugs, leading to unrepresentative macroscopic measurements. Variable amounts of host cell infiltration can also be demonstrated in the untreated control when normal mice are used. The use of nude mice decreases the discrepancy between macroscopic and microscopic evaluation.