Octreotide in advanced prostatic cancer relapsing under hormonal treatment

Since somatostatin analogues have been shown to possess inhibitory activity on prostatic cancer cells in animal models, we studied the clinical effects of the long-acting somatostatin analogue octreotide in the treatment of advanced prostatic cancer. Five patients with metastatic prostatic cancer in relapse under hormonal treatment and with rapidly increasing levels of prostate specific antigen (PSA) received a subcutaneous infusion of octreotide in a dose of 400 to 1,000 micrograms/day for a period of 2 to 6 months. Patients were followed clinically and by monthly measurement of PSA levels. During treatment 3/5 patients showed a temporary halt in rising PSA levels, while another patient had a small decrease. This inhibitory effect however was lost after 1 to 3 months of therapy in 3 patients. The remaining patient died after 4 months before an escape of PSA levels was seen. Side effects consisted of mild diarrhoea in three patients. From this very preliminary data, it appears that octreotide in a dose of 400 to 1,000 micrograms/day may give only a moderate and temporary inhibition of tumor growth in patients with advanced prostatic cancer. Because of the limited effects the study was interrupted prematurely. Since higher doses, other somatostatin-analogues or the combination of LHRH analogues may give better results, further studies are needed to determine the potential therapeutic role of somatostatin-analogues in this group of patients.