Abstract: PD07-05
Sources of Funding: None

Introduction

Updated guidelines from the National Cancer Care Network (NCCN) advocate for DRE screening only in those men with elevated PSA. We sought to investigate the effect of serum PSA levels on the association between DRE and subsequent detection of high-grade prostate cancer (Gleason ≥ 7) in a large, nationally representative cohort.

Methods

We analyzed all men who underwent DRE (n=35,350) within the screening arm of the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening trial for high-grade prostate cancer. With a follow up of 314,033 person-years and 1,612 high-grade cancers detected, we performed age-adjusted competing-risks regression analysis to evaluate the interaction between time varying suspicious DRE and serum PSA.

Results

10-yr cumulative incidence of high-grade cancer was 5.8% (95% C.I. 5.5-6.1). Higher risk was seen among those with suspicious vs. non-suspicious DRE. There was a statistically significant interaction between PSA and DRE, with a smaller increase in relative risk for DRE with higher PSA (p=0.01). However, increases in absolute risk were small and clinically irrelevant for PSA < 2 (2.2% vs 1.1% risk of high grade cancer at 10 years), but of clinical importance for PSA 3-10 (37.5% vs 19.5%). Increases in risk were of equivocal clinical relevance for PSA 2-3 (9.0% vs 6.0%).

Conclusions

DRE demonstrated increasingly prognostic utility when PSA >3, limited utility when PSA <2, and some benefit in the setting of equivocal PSA 2-3. These findings provide support for the NCCN guideline recommendation to restrict DRE to men with higher PSA, as a follow-up test to improve specificity rather than as a primary screening modality to improve sensitivity. Further research is warranted on the value of DRE in men with PSA 2-3.

Funding

None