RESUMO
PURPOSE OF REVIEW: Prostate cancer (PrCa) is the most common cancer in men in the western world and is a major source of morbidity and mortality. Currently, general population PrCa screening is not recommended due to the limitations of the prostate-specific antigen (PSA) test. As such, there is increasing interest in identifying and screening higher-risk groups. The only established risk factors for PrCa are age, ethnicity, and having a family history of PrCa. A significant proportion of PrCa cases are caused by genetic factors. RECENT FINDINGS: Several rare germline variants have been identified that moderately increase risk of PrCa, and targeting screening to these men is proving useful at detecting clinically significant disease. The use of a "polygenic risk score" (PRS) that can calculate a man's personalized risk based on a number of lower-risk, but common genetic variants is the subject of ongoing research. Research efforts are currently focusing on the utility of screening in specific at-risk populations based on ethnicity, such as men of Black Afro-Caribbean descent. Whilst most screening studies have focused on use of PSA testing, the incorporation of additional molecular and genomic biomarkers alongside increasingly sophisticated imaging modalities is being designed to further refine and individualise both the screening and diagnostic pathway. Approximately 10% of men with advanced PrCa have a germline genetic predisposition leading to the opportunity for novel, targeted precision treatments. SUMMARY: The mainstreaming of genomics into the PrCa screening, diagnostic and treatment pathway will soon become standard practice and this review summarises current knowledge on genetic predisposition to PrCa and screening studies that are using genomics within their algorithms to target screening to higher-risk groups of men. Finally, we evaluate the importance of germline genetics beyond screening and diagnostics, and its role in the identification of lethal PrCa and in the selection of targeted treatments for advanced disease.
RESUMO
BACKGROUND: Mutations in BRCA2 cause a higher risk of early-onset aggressive prostate cancer (PrCa). The IMPACT study is evaluating targeted PrCa screening using prostate-specific-antigen (PSA) in men with germline BRCA1/2 mutations. OBJECTIVE: To report the utility of PSA screening, PrCa incidence, positive predictive value of PSA, biopsy, and tumour characteristics after 3 yr of screening, by BRCA status. DESIGN, SETTING, AND PARTICIPANTS: Men aged 40-69 yr with a germline pathogenic BRCA1/2 mutation and male controls testing negative for a familial BRCA1/2 mutation were recruited. Participants underwent PSA screening for 3 yr, and if PSA > 3.0 ng/ml, men were offered prostate biopsy. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: PSA levels, PrCa incidence, and tumour characteristics were evaluated. Statistical analyses included Poisson regression offset by person-year follow-up, chi-square tests for proportion t tests for means, and Kruskal-Wallis for medians. RESULTS AND LIMITATIONS: A total of 3027 patients (2932 unique individuals) were recruited (919 BRCA1 carriers, 709 BRCA1 noncarriers, 902 BRCA2 carriers, and 497 BRCA2 noncarriers). After 3 yr of screening, 527 men had PSA > 3.0 ng/ml, 357 biopsies were performed, and 112 PrCa cases were diagnosed (31 BRCA1 carriers, 19 BRCA1 noncarriers, 47 BRCA2 carriers, and 15 BRCA2 noncarriers). Higher compliance with biopsy was observed in BRCA2 carriers compared with noncarriers (73% vs 60%). Cancer incidence rate per 1000 person years was higher in BRCA2 carriers than in noncarriers (19.4 vs 12.0; p = 0.03); BRCA2 carriers were diagnosed at a younger age (61 vs 64 yr; p = 0.04) and were more likely to have clinically significant disease than BRCA2 noncarriers (77% vs 40%; p = 0.01). No differences in age or tumour characteristics were detected between BRCA1 carriers and BRCA1 noncarriers. The 4 kallikrein marker model discriminated better (area under the curve [AUC] = 0.73) for clinically significant cancer at biopsy than PSA alone (AUC = 0.65). CONCLUSIONS: After 3 yr of screening, compared with noncarriers, BRCA2 mutation carriers were associated with a higher incidence of PrCa, younger age of diagnosis, and clinically significant tumours. Therefore, systematic PSA screening is indicated for men with a BRCA2 mutation. Further follow-up is required to assess the role of screening in BRCA1 mutation carriers. PATIENT SUMMARY: We demonstrate that after 3 yr of prostate-specific antigen (PSA) testing, we detect more serious prostate cancers in men with BRCA2 mutations than in those without these mutations. We recommend that male BRCA2 carriers are offered systematic PSA screening.
