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

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.

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.

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.

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.