Somatostatin analogs and disease control in castration-resistant prostate cancer: different biological behavior? Case series and review of the literature

Aims and background. Castration-resistant prostate cancer is a recent biological behavior where disease can elude androgen deprivation therapy (ADT). Several pathways have been described, including neuroendocrine dedifferentiation. Patients with neuroendocrine dedifferentiation show an increase in chromogranin A (CgA) along with a PSA increase. Our aim was to evaluate the response of patients with castration-resistant prostate cancer and high CgA serum levels after treatment with inhibitors of neuroendocrine cells (somatostatin analogs) in combination with ADT. Methods. From January 2009 to April 2011, 10 patients with castration-resistant prostate cancer and rising PSA levels along with a CgA increase were evaluated. The therapy was based on somatostatin analogs and LHRH anologs. Total PSA and CgA were measured every 2 months. Results. In 9 of the 10 patients, a reduction of the values of pre-treatment CgA was detected, while a reduction of PSA was found in 8 patients. No grade 2 or higher toxicity was recorded. Only 3 patients had grade 1 gastrointestinal toxicity. Time to progression was 13 months. Conclusion. Therapy with somatostatin analogs could increase the therapeutic window of ADT with a low toxicity profile in a subpopulation of patients with castrationresistant prostate cancer who experience a rise in CgA due to neuroendocrine regulation. Copyright - Il Pensiero Scientifico Editore.