Prostate cancer screening using risk stratification based on a multi-state model of genetic variants

Gene‒Prostate-Specific-Antigen-Guided Personalized Screening for Prostate Cancer

(1) Background: A simulation approach for prostate cancer (PrCa) with a prostate-specific antigen (PSA) test incorporating genetic information provides a new avenue for the development of personalized screening for PrCa. Going by the evidence-based principle, we use the simulation method to evaluate the effectiveness of mortality reduction resulting from PSA screening and its utilization using a personalized screening regime as opposed to a universal screening program. (2) Methods: A six-state (normal, over-detected, low-grade, and high-grade PrCa in pre-clinical phase, and low-grade and high-grade PrCa in clinical phase) Markov model with genetic and PSA information was developed after a systematic review of genetic variant studies and dose-dependent PSA studies. This gene‒PSA-guided model was used for personalized risk assessment and risk stratification. A computer-based simulated randomized controlled trial was designed to estimate the reduction of mortality achieved by three different screening methods, personalized screening, universal screening, and a non-screening group. (3) Results: The effectiveness of PrCa mortality reduction for a personalized screening program compared to a non-screening group (22% (9%‒33%)) was similar to that noted in the universal screening group (20% (7%‒21%). However, a personalized screening program could dispense with 26% of unnecessary PSA testing, and avoid over-detection by 2%. (4) Conclusions: Gene‒PSA-guided personalized screening for PrCa leads to fewer unnecessary PSA tests without compromising the benefits of mortality reduction (as happens with the universal screening program).

Screening Men at Increased Risk for Prostate Cancer Diagnosis: Model Estimates of Benefits and Harms

BACKGROUND

Guidelines for PSA screening in subgroups with increased risk of prostate cancer diagnosis due to race or genotype are underdeveloped. Our goal was to investigate types of increased prostate cancer risk and implications for targeted screening.

METHODS

We investigated computer simulation of subgroups with average and hypothetical increased risk(s) of onset of latent disease, progression, and/or cancer-specific death. For each subgroup, we predicted lifetime probabilities of overdiagnosis and life saved under more and less intensive PSA screening strategies. An application estimated risks of onset among BRCA1/2 mutation carriers in the Identification of Men with a genetic predisposition to ProstAte Cancer: Targeted screening in BRCA1/2 mutation carriers and controls (IMPACT) study using maximum likelihood.

RESULTS

Our simulations implied PSA screening can save more lives among subgroups with increased risk than with average risk, but more intensive screening did not always improve harm-benefit trade-offs. IMPACT data were consistent with increased risks of onset among BRCA1 and BRCA2 mutation carriers [HR = 1.05; 95% confidence interval (CI), 0.63-1.59 and HR = 1.81; 95% CI, 1.14-2.78, respectively]. Our analysis suggests screening BRCA2 mutation carriers earlier and more frequently than the average-risk population, but a lower PSA threshold for biopsy is unlikely to improve outcomes.

CONCLUSIONS

Effective screening in men with increased prostate cancer risk depends on the manner in which the risk is increased. More intensive screening is not always optimal.

IMPACT

Guidelines for screening men at increased prostate cancer risk should consider the mechanism inducing the increased risk. Although the benefit of screening may be greater in men with increased risks, more intensive screening is not always appropriate. Cancer Epidemiol Biomarkers Prev; 26(2); 222-7. ©2016 AACR.