Survival Rate and Factors Influencing It in Triptorelin-Castrated Metastatic Prostate Cancer Patients

Abstract

Background: Most newly diagnosed prostate cancers in Benin are metastatic diseases and patients are reluctant to undergo orchiectomy. Still, chemical androgen deprivation therapy is not always available and not every patient can afford it. Thus, it will be interesting to evaluate the results of that therapy in the country. Objective: To analyze the survival rate and factors influencing it in metastatic prostate cancer patients who underwent triptorelin-based androgen deprivation therapy at the former Military Teaching Hospital of Cotonou from January 1, 2012, to December 31, 2022. Patients and Method: Metastatic prostate cancer patients received intragluteal injections of triptorelin 11.25 mg every 3 months. We retrospectively collected follow-up data from the patients’ medical records. By means of the software StataTM version 15, we performed a descriptive analysis of qualitative data. We used Kaplan-Meir method to estimate the overall survival rate in the whole cohort and in specific subgroups of patients. We compared survival rates by using the log-rank test. Results: 68 metastatic prostate cancer patients aged 47-86 years (mean = 69.9) with initial PSA ranging from 24.25 to 6334 ng/mL (mean = 666.1) started triptorelin-based castration. The tumor grade in 21 (33.3%), 14 (22.2%), 15 (23.8), 8 (12.7%), and 5 (7.9%) patients was respectively ISUP grade groups 5, 4, 3, 2, and 1. 15 (22.1%), 4 (5.9%), 2 (2.9%), 1 (1.5%), 11 (16.2%), and 7 (10.3%) patients respectively had hypertension, diabetes mellitus, peptic ulcer, asthma, unilateral or bilateral hydronephrosis, and paralysis. The mean nadir PSA level was 22.5 ng/mL (range: 0.01-220.25). The mean time to nadir PSA level was 8.9 months (range: 3 - 57). The overall survival rate was 42.6%. There was no significant survival difference between age groups (p = 0.475), relating to the presence of diabetes or hypertension (p = 0.757) or to the presence of paralysis or hydronephrosis (p = 0.090). The initial PSA level exerted no significant impact on patients’ survival (p = 0.461). Neither did the time to PSA nadir (p = 0.263). The PSA nadir less than 4 ng/mL (p = 0.005) and the PSA nadir less than 4 ng/mL achieved in 12 months or less (p = 0.002) were predictive of longer survival rate. The difference in survival rate through the ISUP grade groups was not significant (p = 0.061). Conclusion: The overall survival rate was 42.6% at 5 years. Achieving PSA nadir of less than 4 ng/mL in less than 12 months of castration was predictive of longer survival rate in triptorelin-castrated metastatic prostate cancer patients.