Login to Access Video or Poster Abstract: MP77-08
Sources of Funding: None

Introduction

Changes in PSA guidelines since 2012 have led to both lower rates of screening and lower rates of prostate cancer diagnoses. This has been heralded for reduction in over-diagnosis of low risk cancer and criticized based on concern for missed diagnosis of higher risk disease. It is not clear how regions with stringent screening practices may be affected by changed guidelines; for instance, Dartmouth-Hitchcock Medical Center (DHMC) had the lowest rate of PSA screening among Medicare patients in the United States in 2012. In this study, we evaluated trends in biopsy and diagnosis rates at DHMC to assess the impact of changed guidelines in this environment.

Methods

Using a data warehouse query and chart review, we retrospectively analyzed patients at DHMC who underwent a trans-rectal ultrasound guided (TRUS) prostate biopsy January 2011 through March 2016. We excluded patients on active surveillance and those with clinical metastatic disease. Demographic and clinical characteristics were collected and analyzed, stratifying on time. Multivariable analysis was conducted using a priori variables to assess factors associated with higher grade cancer diagnoses. Statistical analysis was performed using SAS 9.4 (Cary, NC).

Results

During the study period, 614 prostate biopsies were performed. The mean age at biopsy was 63.7 (42-87); the mean PSA was 8.2 (0.14-49.9). Pathology results included 44.9% benign, 16.9% Gleason 3+3, and 38.1% ?3+4 disease. The mean PSA at biopsy increased with time (7.2 in 2011 vs 10.1 in 2016; p = 0.0085), while mean age did not (p=0.3645). The proportion of benign results remained stable (46.1% in 2011 vs 45.8% in 2015) however the proportion of low grade disease decreased while intermediate/high grade increased (2011 vs 2015: 21.1% vs 10.8% Gleason 3+3, 32.9% vs 43.3% ?Gleason 3+4, p = 0.0454). On multivariable analysis factors predictive of worse disease included abnormal digital rectal exam (OR 2.19, p-value 0.0076), higher PSA level (OR 1.09, p-value 0.0040), and later biopsy date (OR 1.01, p-value 0.0469).

Conclusions

In an environment of already austere screening practices, there has been a shift in both prostate biopsy criteria and outcomes, namely a rising PSA threshold for biopsy and a 50% decrease in the rate of diagnosis of low risk disease. There has been a concomitant 30% increase in the rate of higher grade disease. These trends demonstrate the potential benefit of more restrained screening practices. Additional study of the downstream effects of changing screening and biopsy practices is needed to ensure these are favorably impacting the overall quality of care.

Funding

None