Ten-Year Trends in Digital Rectal Exam Results and Prostate Cancer Detection: Insights from the PLCO Trial.

Objective: Digital Rectal Examination (DRE) remains an important preventive measure in primary care settings, but a single screening may produce false positives. We sought to explore the trend of abnormal DRE (suspicious and non-suspicious) findings in men with and without prostate cancer. Methods: We utilized data on 34,756 men (1,713 Black and 33,043 White) from the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. Serial DRE measurements were collected over a 10-year follow-up prior to prostate cancer diagnosis. DRE results were categorized as: normal, abnormal non-suspicious, and suspicious DRE. Generalized estimating equation (GEE) model was used to evaluate the trend in suspicious DRE findings over time. Results: After adjusting for potential confounders, the interaction term of time to diagnosis and prostate cancer status was statistically significant indicating a 23.0% increase in the odds of suspicious DRE (OR=1.230, 95% CI: 1.193-1.268) and a 5.2% increase in the odds of non-suspicious DRE (OR=1.052, 95% CI: 1.033-1.072) per year closer to diagnosis. The positive predictive value of abnormal suspicious DRE was 4.74% at 10 years prior to diagnosis, 36.82% at 5 years prior to diagnosis, 60.63% at 2 years prior to diagnosis, and 90.48% at diagnosis. Older age and benign prostatic hyperplasia (BPH) were more likely to have increased suspicious DRE findings. Conclusion: Our results suggest that incorporating serial DRE findings into screening strategies may reduce false positives and improve early detection of clinically significant prostate cancer. This study demonstrates a rising probability of abnormal DRE findings in men with prostate cancer, whereas no temporal change was observed in men without prostate cancer.