New Hormonal Agents in Patients With Nonmetastatic Castration-Resistant Prostate Cancer: Meta-Analysis of Efficacy and Safety Outcomes

Abstract

In the past few years several hormonal agents have been tested in patients with nonmetastatic castration-resistant prostate cancer (nmCRPC) leading to an impressive improvement in terms of metastases-free survival (MFS). We performed a meta-analysis aimed to: (1) estimate the pooled effect of new hormonal compounds in terms of MFS, overall survival (OS) in overall and specific subpopulations; and (2) estimate the effect of high-grade toxicities of these drugs. We identified 881 studies published between January 1, 2010 and February 16, 2018 on PubMed/Medline, Cochrane Library, and Scopus. Three randomized placebo controlled clinical trials were selected (PROSPER, SPARTAN, and ARAMIS). Because of the absence of individual data, all of the analyses performed were made on aggregated data provided in selected studies. We used the inverse variance technique for the meta-analysis of the hazard ratios collected for MFS and OS analysis. Fixed and randomized models were used. Relative risk and 95% confidence intervals and risk difference were estimated considering the number of Grade 3 adverse events in treatment and control arms. Administration of new hormonal compounds in nmCRPC patients led to a significant benefit in MFS in the overall population and in all subgroups analyzed. These agents might also improve OS but longer follow-up is needed to confirm this hypothesis. Indeed results of OS analysis should be carefully evaluated because none of the studies selected provided mature OS data. Administration of these agents resulted in a significant increased risk of treatment-related death, high cardiovascular toxicity, hypertension, fractures, and falls. Administration of new hormonal compounds prolongs the time of metastases occurrence and might prolong also survival in patients with nmCRPC. Treatment-related toxicity is an important issue because these agents increase the risk of death, cardiovascular toxicity, hypertension, fractures, and risk of falls.