In 58 patients with progressive hormone-resistant metastatic cancer of the prostate, prostate-specific antigen (PSA) greater than 100 micrograms/l, haemoglobin less than 12.0 g/dl and pronounced fatigue were found to be independent adverse prognostic factors. These risk factors distinguished a subgroup of patients with a median survival of 9 months (none or only 1 risk factor present) from a subgroup with a median survival of 4 months (greater than or equal to 2 risk factors present). The clinician should be reluctant to enter patients from the second group into complicated and resource-demanding clinical studies, particularly if such trials require frequent and inconvenient follow-up examinations.