Modern principles of diagnosis and treatment of patients with neuroendocrine carcinoma of the prostate

Abstract

Background. Prostate cancer (PCa) is well-known as the 2nd leading cause of death from malignant neoplasms among the males from developed countries. One of the variants of the disease - neuroendocrine carcinoma of the prostate (NECP) -manifests itself as the form of castration-resistant PCa. Distinctive manifestations of NECP include a low level of serum prostate specific antigen (PSA), a high potential rate of metastasis, and resistance to hormone replacement therapy. There are very few medical publications on the possibilities of diagnosis and therapy of this type of tumor.The objective of the study is to review the current foundations of pathogenesis, methods of diagnosis and treatment of patients with NECP.Materials and methods. The data of modern medical literature from the PubMed/Crossref archives, from the Elsevier and Scopus databases for 1991-2020 were studied. The materials on the epidemiology and pathogenesis of NECP, as well as the methods of diagnosis and treatment of patients with this pathology are summarized. A comparative analysis of the levels of neuroendocrine markers in castration-resistant and localized forms of PCa was carried out. The schemes of combination therapy of NECP with the use of somatostatin analogs are considered.Results. The detection rate of NECP is reduced due to the blurred clinical picture and morphological characteristics similar to poorly differentiated carcinoma. The basis for the diagnosis of NECP is the determination of the levels of neuronal markers - chromogranin A, neuron-specific enolase, and a number of potentially mitogenic hormones, including PTHrP, NT, serotonin, bombesin, calcitonin, and thyroid-stimulating hormone. The worst prognosis was observed in patients with initially high levels of chromogranin A, which emphasizes the high significance of this indicator for monitoring NECP. The drug of choice in the treatment of patients with this pathology is the somatostatin analogue octreotide-depot, the use of which in combination with hormone replacement therapy leads to stabilization of PCa in 50 % of cases. During therapy with an analogue of somatostatin alone or in cases of tumor progression against the background of chemotherapy, a decrease in PSA level is noted in 50-60 % of cases, and PSA level stabilization - in 41.7-53.3 %.Conclusion. We founded an insufficient number of randomized clinical trials of NECP, therefore, the prognosis of the development of this pathology remains completely unclear. The use of somatostatin analogues, along with targeted therapy, is the main choice of therapy for NECP, but requires further study in the program of randomized trials. If a positive result is obtained, it will be possible to use somatostatin analogs more widely to improve the quality and increase the life expectancy of patients with NECP.