A reexamination of the stable category for evaluating response in patients with advanced prostate cancer.

Stable response to therapy in patients with advanced prostate cancer, as experienced in clinical trials of the National Prostatic Cancer Project (NPCP) has been re-examined. Data from 10 completed trials, totaling over 1300 patients, have been examined for survival patterns within categories of response to therapy. Survival patterns, for patients alive at 12 weeks, were significantly poorer for patients who were categorized as progressors after 12 weeks on treatment than for those who were categorized as stable or as partial regressions. Furthermore, comparisons of survival patterns for those patients who were categorized as stable or partial regression revealed no statistically significant differences between them. The concerns over the use of stable as an indicator of response and the problems in establishing its true meaning are discussed. All things considered, the use of stable is a valid means to evaluate the status of patients in clinical trials of treatment modalities for advanced cancer of the prostate.