Men with a susceptibility to prostate cancer and the role of genetic based screening.

Prostate cancer is the second most common malignancy affecting men worldwide, and the commonest affecting men of African descent. Significant diagnostic and therapeutic advances have been made in the past decade. Improvements in the accuracy of prostate cancer diagnosis include the uptake of multi-parametric MRI and a shift towards targeted biopsy. We also now have more life-prolonging systemic and hormonal therapies for men with advanced disease at our disposal than ever before. However, the development of robust screening tools and targeted screening programs has not followed at the same pace. Evidence to support population-based screening remains unclear, with the use of PSA as a screening test limiting our ability to discriminate between clinically significant and insignificant disease. Prostate cancer has a large heritable component. Given that most men without risk factors have a low lifetime risk of developing lethal prostate cancer, much work is being done to further our knowledge of how we can best screen men in higher risk categories, such as those with a family history (FH) of the disease or those of African ancestry. These men have been reported to carry upwards of a two-fold increased risk of developing the disease at an earlier age, with evidence suggesting poorer survival outcomes. In men with a FH of prostate cancer, this is felt to be due to rare, high-penetrance mutations and the presence of multiple, common low penetrance alleles, with men carrying specific germline mutations in the BRCA and other DNA repair genes at particularly high risk. To date, large scale genome-wide association studies (GWAS) have led to the discovery of approximately 170 single nucleotide polymorphisms (SNPs) associated with prostate cancer risk, allowing over 30% of prostate cancer risk to be explained. Genomic tests, utilising somatic (prostate biopsy) tissue can also predict the risk of unfavourable pathology, biochemical recurrence and the likelihood of metastatic disease using gene expression. Targeted screening studies are currently under way in men with DNA repair mutations, men with a FH and those of Afro-Caribbean ethnicity which will greater inform our understanding of disease incidence and behaviour in these men, treatment outcomes and developing the most appropriate screening regime for such men. Incorporating a patient's genetic mutation status into risk algorithms allows us an opportunity to develop targeted screening programs for men in whom early cancer detection and treatment will positively influence survival, and in the process offer male family members of affected men the chance to be counselled and screened accordingly

Homeobox B13 G84E Mutation and Prostate Cancer Risk.

BackgroundThe homeobox B13 (HOXB13) G84E mutation has been recommended for use in genetic counselling for prostate cancer (PCa), but the magnitude of PCa risk conferred by this mutation is uncertain.ObjectiveTo obtain precise risk estimates for mutation carriers and information on how these vary by family history and other factors.Design, setting, and participantsTwo-fold: a systematic review and meta-analysis of published risk estimates, and a kin-cohort study comprising pedigree data on 11983 PCa patients enrolled during 1993-2014 from 189 UK hospitals and who had been genotyped for HOXB13 G84E.Outcome measurements and statistical analysisRelative and absolute PCa risks. Complex segregation analysis with ascertainment adjustment to derive age-specific risks applicable to the population, and to investigate how these vary by family history and birth cohort.Results and limitationsA meta-analysis of case-control studies revealed significant heterogeneity between reported relative risks (RRs; range: 0.95-33.0, pConclusionsPCa risks for HOXB13 G84E mutation carriers are heterogeneous. Counselling should not be based on average risk estimates but on age-specific absolute risk estimates tailored to individual mutation carriers' family history and birth cohort.Patient summaryMen who carry a hereditary mutation in the homeobox B13 (HOXB13) gene have a higher than average risk for developing prostate cancer. In our study, we examined a large number of families of men with prostate cancer recruited across UK hospitals, to assess what other factors may contribute to this risk and to assess whether we could create a precise model to help in predicting a man's prostate cancer risk. We found that the risk of developing prostate cancer in men who carry this genetic mutation is also affected by a family history of prostate cancer and their year of birth. This information can be used to assess more personalised prostate cancer risks to men who carry HOXB13 mutations and hence better counsel them on more personalised risk management options, such as tailoring prostate cancer screening frequency

A prospective prostate cancer screening programme for men with pathogenic variants in mismatch repair genes (IMPACT): initial results from an international prospective study.

Funder: Victorian Cancer AgencyFunder: NIHR Manchester Biomedical Research CentreFunder: Cancer Research UKFunder: Cancer Council TasmaniaFunder: Instituto de Salud Carlos IIIFunder: Cancer AustraliaFunder: NIHR Oxford Biomedical Research CentreFunder: Fundación Científica de la Asociación Española Contra el CáncerFunder: Cancer Council South AustraliaFunder: Swedish Cancer SocietyFunder: NIHR Cambridge Biomedical Research CentreFunder: Institut Català de la SalutFunder: Cancer Council VictoriaFunder: Prostate Cancer Foundation of AustraliaFunder: National Institutes of HealthBACKGROUND: Lynch syndrome is a rare familial cancer syndrome caused by pathogenic variants in the mismatch repair genes MLH1, MSH2, MSH6, or PMS2, that cause predisposition to various cancers, predominantly colorectal and endometrial cancer. Data are emerging that pathogenic variants in mismatch repair genes increase the risk of early-onset aggressive prostate cancer. The IMPACT study is prospectively assessing prostate-specific antigen (PSA) screening in men with germline mismatch repair pathogenic variants. Here, we report the usefulness of PSA screening, prostate cancer incidence, and tumour characteristics after the first screening round in men with and without these germline pathogenic variants. METHODS: The IMPACT study is an international, prospective study. Men aged 40-69 years without a previous prostate cancer diagnosis and with a known germline pathogenic variant in the MLH1, MSH2, or MSH6 gene, and age-matched male controls who tested negative for a familial pathogenic variant in these genes were recruited from 34 genetic and urology clinics in eight countries, and underwent a baseline PSA screening. Men who had a PSA level higher than 3·0 ng/mL were offered a transrectal, ultrasound-guided, prostate biopsy and a histopathological analysis was done. All participants are undergoing a minimum of 5 years' annual screening. The primary endpoint was to determine the incidence, stage, and pathology of screening-detected prostate cancer in carriers of pathogenic variants compared with non-carrier controls. We used Fisher's exact test to compare the number of cases, cancer incidence, and positive predictive values of the PSA cutoff and biopsy between carriers and non-carriers and the differences between disease types (ie, cancer vs no cancer, clinically significant cancer vs no cancer). We assessed screening outcomes and tumour characteristics by pathogenic variant status. Here we present results from the first round of PSA screening in the IMPACT study. This study is registered with ClinicalTrials.gov, NCT00261456, and is now closed to accrual. FINDINGS: Between Sept 28, 2012, and March 1, 2020, 828 men were recruited (644 carriers of mismatch repair pathogenic variants [204 carriers of MLH1, 305 carriers of MSH2, and 135 carriers of MSH6] and 184 non-carrier controls [65 non-carriers of MLH1, 76 non-carriers of MSH2, and 43 non-carriers of MSH6]), and in order to boost the sample size for the non-carrier control groups, we randomly selected 134 non-carriers from the BRCA1 and BRCA2 cohort of the IMPACT study, who were included in all three non-carrier cohorts. Men were predominantly of European ancestry (899 [93%] of 953 with available data), with a mean age of 52·8 years (SD 8·3). Within the first screening round, 56 (6%) men had a PSA concentration of more than 3·0 ng/mL and 35 (4%) biopsies were done. The overall incidence of prostate cancer was 1·9% (18 of 962; 95% CI 1·1-2·9). The incidence among MSH2 carriers was 4·3% (13 of 305; 95% CI 2·3-7·2), MSH2 non-carrier controls was 0·5% (one of 210; 0·0-2·6), MSH6 carriers was 3·0% (four of 135; 0·8-7·4), and none were detected among the MLH1 carriers, MLH1 non-carrier controls, and MSH6 non-carrier controls. Prostate cancer incidence, using a PSA threshold of higher than 3·0 ng/mL, was higher in MSH2 carriers than in MSH2 non-carrier controls (4·3% vs 0·5%; p=0·011) and MSH6 carriers than MSH6 non-carrier controls (3·0% vs 0%; p=0·034). The overall positive predictive value of biopsy using a PSA threshold of 3·0 ng/mL was 51·4% (95% CI 34·0-68·6), and the overall positive predictive value of a PSA threshold of 3·0 ng/mL was 32·1% (20·3-46·0). INTERPRETATION: After the first screening round, carriers of MSH2 and MSH6 pathogenic variants had a higher incidence of prostate cancer compared with age-matched non-carrier controls. These findings support the use of targeted PSA screening in these men to identify those with clinically significant prostate cancer. Further annual screening rounds will need to confirm these findings. FUNDING: Cancer Research UK, The Ronald and Rita McAulay Foundation, the National Institute for Health Research support to Biomedical Research Centres (The Institute of Cancer Research and Royal Marsden NHS Foundation Trust; Oxford; Manchester and the Cambridge Clinical Research Centre), Mr and Mrs Jack Baker, the Cancer Council of Tasmania, Cancer Australia, Prostate Cancer Foundation of Australia, Cancer Council of Victoria, Cancer Council of South Australia, the Victorian Cancer Agency, Cancer Australia, Prostate Cancer Foundation of Australia, Asociación Española Contra el Cáncer (AECC), the Instituto de Salud Carlos III, Fondo Europeo de Desarrollo Regional (FEDER), the Institut Català de la Salut, Autonomous Government of Catalonia, Fundação para a Ciência e a Tecnologia, National Institutes of Health National Cancer Institute, Swedish Cancer Society, General Hospital in Malmö Foundation for Combating Cancer

Incorporating germline genetics into personalised risk-assessment in the detection of prostate cancer in men with an elevated genetic risk

Hypothesis - Prostate biopsy outcomes for men with a genetic predisposition to prostate cancer (PrCa) can be predicted from germline genetic profiling and clinical factors. Prostate cancer (PrCa) is the second most common male malignancy worldwide and has a large heritable component. the use of prostate specific antigen (PSA) as a screening test has limitations in both diagnostic accuracy and inability to discriminate between clinically significant and insignificant disease. Given that most men have a low lifetime risk of developing lethal PrCa, a proposed improved screening strategy could target certain populations of men at increased risk due to a genetic predisposition such as those with a family history (GH) of prostate cancer. To date, approximately 170 common variants (SNPs) associated with PrCa risk exist and can be detected by analysing germline DNA. A polygenic risk score (PRS) can assign men a risk category. The use of prostate multiparametric MRI (mpMRI) has become the standard of care in men with a clinical suspicion of PrCa, with its clinical utility proving useful in helping target prostate biopsy towards a diagnosis of clinically significant prostate cancer. The clinical utility of mpMRI in men without a clinical suspicion of PrCa, but at increased risk of PrCa is undefined. The PROFILE study offers up front mpMRI of the prostate and biopsy to men with a FH of PrCa, regardless of PSA in addition to SNP analysis. This thesis examined the association of PRS with biopsy outcome in addition to known clinical risk variables and biopsy outcome. For this thesis, I performed an interim analysis of the PROFILE study participants' mpMRI, PRS and biopsy outcomes. The incidence of PrCa was 30%, occurring across a spectrum of PSA values, but with 70% occurring at a PSA of 3.0ng/ml or less and 38% of significant cancers occurring at a PSA of 3.0ng/ml or less. I found that PRS was associated with cancer detection and when men were categorised into percentiles of risk, those in the top 20% were the most affected. mpMRI performed well in detecting clinically significant prostate cancer, and a PIRADS 1-2 MRI showed high sensitivity at ruling out clinically significant disease. In men with an abnormal mpMRI, their predicted probability of cancer detection changed according to PRS. Overall mpMRI did not appear as specific in clinically significant caner detection compared to PROMIS data, which is important to recognise in the use of PiRADS reporting in young men with a FH of PrCa if used as a risk-stratification or diagnostic tool on its own. Both PRS and MRI have the potential to play an important role in risk-stratifying men with a FH of PrCa and incorporation into targeted screening algorithms

Genetic predisposition to prostate cancer: an update.

Improvements in DNA sequencing technology and discoveries made by large scale genome-wide association studies have led to enormous insight into the role of genetic variation in prostate cancer risk. High-risk prostate cancer risk predisposition genes exist in addition to common germline variants conferring low-moderate risk, which together account for over a third of familial prostate cancer risk. Identifying men with additional risk factors such as genetic variants or a positive family history is of clinical importance, as men with such risk factors have a higher incidence of prostate cancer with some evidence to suggest diagnosis at a younger age and poorer outcomes. The medical community remains in disagreement on the benefits of a population prostate cancer screening programme reliant on PSA testing. A reduction in mortality has been demonstrated in many studies, but at the cost of significant amounts of overdiagnosis and overtreatment. Developing targeted screening strategies for high-risk men is currently the subject of investigation in a number of prospective studies. At present, approximately 38% of the familial risk of PrCa can be explained based on published SNPs, with men in the top 1% of the risk profile having a 5.71-fold increase in risk of developing cancer compared with controls. With approximately 170 prostate cancer susceptibility loci now identified in European populations, there is scope to explore the clinical utility of genetic testing and genetic-risk scores in prostate cancer screening and risk stratification, with such data in non-European populations eagerly awaited. This review will focus on both the rare and common germline genetic variation involved in hereditary and familial prostate cancer, and discuss ongoing research in exploring the role of targeted screening in this high-risk group of men

Interim Results from the IMPACT Study : Evidence for Prostate-specific Antigen Screening in BRCA2 Mutation Carriers

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. 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. 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. 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. 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). 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