Profile study: Genetic prostate cancer risk stratification for targeted screening.

Abstract

5054 Background: Prostate cancer (PC) screening is controversial and better approaches are needed, including a better assessment of individualized PC risk. Several studies have identified a number of common single nucleotide polymorphisms (SNPs) that confer a cumulative risk of PC. We have explored the potential role of genetic markers in identifying men who should be selectively targeted for screening in a population with increased risk of PC due to family history (FH) of the disease. Methods: PROFILE has been developed as a pilot study. The primary aim is to determine the feasibility of targeted PC screening using prostatic biopsy (PB) and its association with specific genetic profiles in men with FH. Secondary aims are to evaluate the role of PSA and Diffusion Weighted MRI (DW-MRI) as screening tools in this population. From December 2010 men aged 40-69 with FH of PC were invited into the study until 100 men were enrolled. Blood samples were provided for PSA and DNA extraction. The cumulative SNP risk scores for each patient were calculated by summing 59 risk alleles for each locus using the weighted effect as estimated in previous studies (log-additive model). DW-MRI was performed in 50 patients. All participants were asked to undergo a 10 core PB regardless of baseline PSA. Those who declined PB have been excluded from this analysis. Data on side effects and cancer worry were also collected. Results: 35% of invited men entered the study. Median age was 53 yrs (40-69) and median PSA was 1.15. Ninety men accepted to undergo a PB as primary PC screening. Twenty-two tumours were found and 45% of them were clinically significant [Median age 64yrs (47-69), median PSA 5.4 (0.91-9.3)]. 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 better in men with PSA<3(AUC 0.63). No severe side effect or adverse psychosocial variables were noted. Conclusions: Our results indicate that PB is acceptable as a means of PC screening in men with FH of PC. Overall, DW-MRI and PSA were more predictive of PC than the genetic risk score. As more SNPs are found, a larger study is warranted to evaluate their role in the PC screening algorithm.