Melatonin increases overall survival of prostate cancer patients with poor prognosis after combined hormone radiation treatment

Background: The antitumor and immunomodulating activities of melatonin are widely known. These activities are based upon the multifactorial mechanism of action on various links of carcinogenesis. In the present paper, the long-term results of the clinical use of melatonin in the combined treatment of patients with prostate cancer of various risk groups were evaluated. Materials and Methods: A retrospective study included 955 patients of various stages of prostate cancer (PCa) who received combined hormone radiation treatment from 2000 to 2019. Comprehensive statistical methods were used to analyze the overall survival rate of PCa patients treated with melatonin in various prognosis groups. Results: The overall survival rate of PCa patients with favorable and intermediate prognoses treated or not treated with melatonin was not statistically significantly different. In the poor prognosis group, the median overall survival in patients taking the drug was 153.5 months versus 64.0 months in patients not using it (p < 0.0001). The 5-year overall survival rates in the research and control groups were 66.8 ± 1.9 and 53.7 ± 2.6 (p < 0.0001) respectively. In a multivariate analysis, melatonin administration proved to be an independent prognostic factor and reduced the risk of death of PCa patients by more than twice (p < 0.0001). Conclusions: The multicomponent antitumor effect of melatonin is fully realized and clearly demonstrated in treatment of PCa patients with poor prognosis with a set of unfavorable factors of the tumor progression.