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Purpose: The prevalence of homologous recombination repair gene mutations (HRRm) in patients with metastatic castration-resistant prostate cancer (mCRPC) in Latin America and the Caribbean (LAC) is unknown. Prevalence of homologous Recombination repair (HRR) gene mutatiOns in patientS with metastatic castration resistant ProstatE Cancer in LaTin America (PROSPECT) aimed to determine this prevalence and to describe the demographic and clinical characteristics of the participants., Materials and Methods: This was a prospective, cross-sectional, multicenter study across 11 cancer centers in seven LAC countries. After informed consent, all eligible participants underwent genomic testing by provided blood samples for germline HRR testing; they also provided PC tissue blocks if available for somatic HRR testing., Results: Between April 2021 and April 2022, 387 patients (median age, 70 years [49-89], 94.3% Eastern Cooperative Oncology Group 0-1) with mCRPC were enrolled in the study. Almost 40% of them had a family history of cancer, and the overall time from their initial PC and mCRPC diagnosis was 3 years and 1 year, respectively. The overall prevalence of germline HRRm was 4.2%. The mutations detected included the genes CHEK2 (n = 4, 1%), ATM (n = 3, 0.8%), BRCA2 (n = 3, 0.8%), BRIP1 (n = 2, 0.5%), RAD51B (n = 2, 0.5%), BRCA1 (n = 1, 0.3%), and MRE11 (n = 1, 0.3%). The prevalence of somatic HRRm could not be assessed because of high HRR testing failure rates (79%, 199/251) associated with insufficient DNA, absence of tumor cells, and poor-quality DNA., Conclusion: Despite the study's limitations, to our knowledge, PROSPECT was the first attempt to describe the prevalence of HRRm in patients with PC from LAC. Notably, the germline HRRm prevalence in this study was inferior to that observed in North American and European populations. The somatic HRR testing barriers identified are being addressed by several projects to improve access to HRR testing and biomarker-based therapies in LAC.

In castration-resistant prostate cancer (CRPC) patients, observational studies have reported that statins may boost the antitumor activity of abiraterone (AA) and data suggest an improvement in efficacy; conclusions with vitamin D are less clear but an eventual benefit has been pointed. We conducted a post hoc analysis of individual patient data of CRPC patients treated with prednisone and/or AA with or without statins/vitamin D on randomized clinical trials. In the COU-AA-301 trial, use of AA with statin and vitamin D reduced the risk of death by 38% (p = 0.0007) while AA alone was associated with a decrease of 10% (p = 0.025), compared to prednisone alone. Meanwhile, in the COU-AA-302 trial, use of AA plus statin plus vitamin D was associated with a reduced risk of death of 26% (p = 0.0054). In this data analysis from two prospective randomized clinical trials, statin and vitamin D use was associated with superior overall survival in metastatic CRPC patients treated with AA and prednisone. To our knowledge, this is the first report suggesting the impact of statin plus vitamin D in this population. New strategies using big data may help to clarify these questions easily and in a most cost-effective approach.

Introduction: Although increasing numbers of therapies with proven survival benefits have become available for metastatic castration-resistant prostate cancer (mCRPC), including radium-223, there is still a need for reliable biomarkers that provide information about clinically meaningful outcomes and treatment responses., Materials and Methods: This study was a translational study that was conducted prospectively by the Spanish Oncology Genito-Urinary Group and included 45 patients with histologically confirmed mCRPC who were treated with radium-223. The primary response outcome was defined by a decline in circulating tumor cells (CTCs) of > 50% from baseline or a CTC count of ≤ 5 cells/7.5 mL at cycle 3 of radium-223. We also assessed response according to prostate-specific antigen and alkaline phosphatase levels. CTCs were evaluated as prognostic factor for treatment completion with radium-223 treatment. Kaplan-Meier estimates of survival were calculated for the global population and were correlated with biomarker response outcomes., Results: Significantly, more patients with baseline CTC counts ≤ 5/7.5 mL, which are indicative of better prognoses, completed the 6 injections of therapy than those with CTC counts > 5 (16/22; 73% vs. 6/20; 30%, respectively; P = .012). The median overall survival was 16 months. Survival was significantly decreased in patients with baseline CTC counts > 5 cells/7.5 mL (7 months; P = .026) and baseline alkaline phosphatase levels ≥ 220 U/L (8 months; P = .028)., Conclusions: CTCs hold significant promise as a prognostic factor for survival and completing treatment prior to the initiation of bone-targeted radium-223 therapy. These findings may help to guide the use of radium-223 in patients with mCRPC., (Copyright © 2018 Elsevier Inc. All rights reserved.)