Criteria for evaluating hormones in the 7,12-dimethylbenz[a]-anthracene-induced mammary tumor-rat experimental chemotherapy system.

Two criteria were used to measure the effectiveness of hormones in the therapy of mammary tumors induced in SpragueDawley rats by 7,12-dimethylbenz[a]anthraeene. These were complete regression of all tumors in the host and duration of complete remission. Well-established, growing mammary tumors were treated with testosterone propionate or 2o~-methyldihydrotestosterone propionate. There was no significant~ difference between the effects of the two androgens, at equivalent doses, with respect to production of complete remissions. However, the median for duration of complete remission in rats treated with 2a-met, hyldihydrotestosterone propionate was significantly greater than for testosterone propionate. The results suggest that duration of remission is a useful adjunct for disdosing differences between compounds with similar abilities to cause tumor regression.