Prostate cancer: evaluation of response to treatment, response criteria, and the need for standardization of the reporting of results.

Response criteria and the reporting of results in clinical trials on drug therapy of stage D prostate cancer were evaluated by examination of studies listed in the Index Medicus 1980-1984. During this 5-year period, 70 studies (51 phase II and 16 phase III) were listed, comprising 3184 evaluable patients. Among 346 patients reported as having evaluable disease according to the WHO criteria, 198 had well-defined evaluable disease. A variety of response criteria were used, the NPCP criteria being the most frequent. Only three studies included solely patients with evaluable disease according to the WHO criteria. Reporting of results was often inadequate. The value of the most frequently used response parameters such as acid phosphatase, bone scan, per-rectal ultrasound, CT scan, bone pain and performance status is discussed. A system to standardise the reporting of results is proposed.