Radiolabelled somatostatin analog therapy in prostate cancer: current status and future directions

Natural somatostatin is characterized as an inhibitory peptide and had anti-neoplastic actions. The effect of somatostatin is mediated via specific somatostatin receptors (SSTRs). Clinical trials have demonstrated therapeutic applications of radionuclide labeled somatostatin analogues in many tumors bearing the receptors. In prostate cancer, significance of neuroendocrine cells remains unclear, there were conflicting data about occurrence and localization of SSTRs. Therefore, radionuclide labeled somatostatin analog therapy is not applied to prostate cancer clinically, experimental trials with non-radioactive analogues have been disappointing. More efforts need to be made for evaluation of potential applications of somatostatin analog therapy in prostate cancer, for example, transfection of the receptor gene to increase binding of analogues to the tumor cells, improvement of radionuclide delivery and combinations of different therapeutic modalities.