The PROFILE feasibility study: Genetic prostate cancer risk stratification for targeted screening.

Abstract

22 Background: Prostate cancer (PC) screening is controversial and a better assessment of individualized PC risk is needed. Several single nucleotide polymorphisms (SNPs) conferring a cumulative risk of PC have been identified. We have explored the potential role of genetic markers for targeted screening in a population with increased risk of PC due to family history (FH). Methods: PROFILE was developed as a pilot study to determine the feasibility of targeted PC screening using prostatic biopsy (PB) and its association with specific genetic profiles in men with FH. We also evaluated the role of PSA and Diffusion Weighted MRI (DW-MRI) as screening tools. One hundred sixteen men age 40 to 69 with FH of PC were enrolled between October 2009 and December 2012. Cumulative SNP risk scores were calculated by summing 59 risk alleles for each locus using the weighted effect (log-additive model). DW-MRI was performed in 50 patients. Participants were asked to undergo a 10 core PB regardless of baseline PSA. Results: Median age 53 (40 to 69) and median PSA was 1.15. One hundred and two men accepted to undergo a PB as primary PC screening. Twenty-three tumours were found (22.5% of biopsies) as well as seven men diagnosed with atypical small acinar proliferation (ASAP) (6.8%) and eight men with high-grade prostatic intraepithelial neoplasia (HG-PIN) (7.8%). In total 37.1% received an abnormal result. Out of the diagnosed PC 41% were intermediate or high risk and requiring treatment, which compares with 24% in general population screening. The predictive performance of DW-MRI, PSA, genetic model and genetic model plus PSA measured by AUC were: 0.85, 0.73, 0.57 and 0.74, respectively. The genetic model performed best in men with a normal PSA of <3(AUC 0.63). Analyses of a 78 SNP profile from the recent COGS results are underway. Conclusions: Ourresults indicate that PB is acceptable for PC screening in men with FH of PC. The significant AUC for DW-MRI would warrant a larger study. The incidence of ASAP is higher in this group than the general population.The SNP risk score was more predictive in men with PSA less than three where PB would not normally be undertaken, therefore an expanded study to investigate the role of genetic profiling in directing PB in PC screening is indicated.