Risk Prediction of Prostate Cancer with Single Nucleotide Polymorphisms and Prostate Specific Antigen.

PURPOSE: Combined information on single nucleotide polymorphisms and prostate specific antigen offers opportunities to improve the performance of screening by risk stratification. We aimed to predict the risk of prostate cancer based on prostate specific antigen together with single nucleotide polymorphism information. MATERIALS AND METHODS: We performed a prospective study of 20,575 men with prostate specific antigen testing and 4,967 with a polygenic risk score for prostate cancer based on 66 single nucleotide polymorphisms from the Finnish population based screening trial of prostate cancer and 5,269 samples of 7 single nucleotide polymorphisms from the Finnish prostate cancer DNA study. A Bayesian predictive model was built to estimate the risk of prostate cancer by sequentially combining genetic information with prostate specific antigen compared with prostate specific antigen alone in study subjects limited to those with prostate specific antigen 4 ng/ml or above. RESULTS: The posterior odds of prostate cancer based on 7 single nucleotide polymorphisms together with the prostate specific antigen level ranged from 3.7 at 4 ng/ml, 14.2 at 6 and 40.7 at 8 to 98.2 at 10 ng/ml. The ROC AUC was elevated to 88.8% (95% CI 88.6-89.1) for prostate specific antigen combined with the risk score based on 7 single nucleotide polymorphisms compared with 70.1% (95% CI 69.6-70.7) for prostate specific antigen alone. It was further escalated to 96.7% (95% CI 96.5-96.9) when all prostate cancer susceptibility polygenes were combined. CONCLUSIONS: Expedient use of multiple genetic variants together with information on prostate specific antigen levels better predicts the risk of prostate cancer than prostate specific antigen alone and allows for higher prostate specific antigen cutoffs. Combined information also provides a basis for risk stratification which can be used to optimize the performance of prostate cancer screening.

Association Between Colorectal Cancer Mortality and Gradient Fecal Hemoglobin Concentration in Colonoscopy Noncompliers.

Background: To what extent the risk for colorectal cancer (CRC) death among noncompliers of colonoscopy is elevated following positive fecal immunological testing and whether the elevated risk varies with the fecal hemoglobin concentration (f-Hb) and location of CRC have not been researched. Methods: We used data on 59 389 individuals (4.0%) among 1 489 937 Taiwanese screenees age 50 to 69 years with f-Hb 20 µg hemoglobin or more per gram of feces from 2004 to 2009. They were classified into 41 995 who received colonoscopy and 10 778 who received no confirmatory examination; the latter was categorized into three risk groups according to f-Hb (20-49, 50-99, and 100+). Mortality from CRC as the primary end point was monitored until December 31, 2012. Results: A 1.64-fold (95% confidence interval [CI] = 1.32 to 2.04) increased risk for CRC death for the noncolonoscopy group as opposed to the colonoscopy group adjusting for differences in baseline characteristics. A gradient relationship was noted between cumulative mortality and age- and sex-adjusted f-Hb categories with 1.31-fold (95% CI = 1.04 to 1.71), 2.21-fold (95% CI = 1.55 to 3.34), and 2.53-fold (95% CI = 1.95 to 3.43) increased risk, respectively, for the 20-49, 50-99, and 100+ risk groups in the noncolonoscopy group compared with the colonoscopy group. The noncolonoscopy group led to a statistically significant 1.75-fold increased risk (95% CI = 1.35 to 2.33) for CRC of the distal colon but a statistically nonsignificant 1.11-fold increased risk (95% CI = 0.70 to 1.75) for the proximal colon, compared with the colonoscopy group. When the comparator was limited to subjects whose colonoscopy was completed to the cecum, the statistically significantly elevated risk for CRC mortality was seen for both distal and proximal colon in the noncolonoscopy group. Conclusions: After a positive fecal immunochemical test, colonoscopy can reduce by about half the number of deaths from CRC. Among colonoscopy noncompliers, higher f-Hb is associated with an increased risk of mortality from CRC in a dose-response manner.