The specific objective of this research is to continue to evaluate the clinical effectiveness of non-hormonal chemotherapeutic agents in the treatment of patients with advanced prostatic cancer whose cancers fail to respond, or no longer respond, to existing hormonal therapy. Under our present grant and in collaboration with four other centers, we probably will have finished studies under Protocols 100 and 200 in which comparisons are being made between Standard Treatment (analgesics or radiotherapy for pain relief and surgery for relief of urinary obstruction) and 5-Fluorouracil and Cyclophosphamide, and between Standard Treatment and Estracyt and Streptozotocin. Also, we should be nearing completion of studies under Protocol 300 in which we compare the effectiveness of Cyclophosphamide with Procarbazine and DTIC. Approximately 50 patients are entered under each arm of each study, with treatment lasting for at least 12 weeks, those showing progression of their disease being crossed-over to the other drug of the pair. Basic decisions to evaluate other chemotherapeutic agents will be made by members of the National Prostatic Cancer Project based on animal and clinical studies and in counsel with the National Cancer Institute.