This article reviews the serial bone scans of 149 of 327 patients entered into a randomized prospective trial comparing orchidectomy versus zoladex and flutamide in patients with metastatic prostatic cancer. Attention is drawn to the difficulty of evaluating the response rate and of the importance of tumor load in determining survival. The use of sequential bone scans once the diagnosis of metastatic disease has been confirmed is of questionable value as the scans are expensive and contribute little to the further management of the patient in the absence of symptoms requiring relief.