Impact of the U.S. Preventive Services Task Force recommendations against prostate specific antigen screening on prostate biopsy and cancer detection rates

Abstract

Purpose: We determined if the USPSTF recommendation against prostate specific antigen screening was associated with a change in biopsy and cancer detection rates.

Materials and methods: We conducted a time series analysis (October 2008 to June 2013) of prostate biopsies performed at University Health Network (Toronto). Biopsies for active surveillance or solely targeting magnetic resonance imaging detected lesions were excluded from study. Interventional ARIMA models with step functions were used to examine changes in the number of biopsies performed and cancers detected per month. Low risk prostate cancer was defined as no Gleason pattern 4 or greater, 3 or fewer cores involved, or 1/3 or less of the total number of cores involved, and no core with greater than 50% cancer involvement. Intermediate to high grade prostate cancer was defined as Gleason 7-10.

Results: A total of 3,408 biopsies were performed and 1,601 (47.0%) prostate cancers were detected (low risk prostate cancer 563 [16.5%], intermediate to high grade prostate cancer 914 [26.8%]). The median number of biopsies per month decreased from 58.0 (IQR 54.5-63.0) before the recommendations to 35.5 (IQR 27.0-41.0) afterward (p=0.003), while the median number of patients undergoing first-time biopsy decreased from 42.5 (IQR 37.5-45.5) to 24.0 (IQR 19.0-32.5, p=0.025). The median number of low risk prostate cancers detected per month decreased from 8.5 (IQR 6.5-10.5) to 5.5 (IQR 4.0-7.0, p=0.012), while the median number of intermediate to high grade prostate cancers per month decreased from 17.5 (IQR 14.5-21.5) to 10.0 (IQR 9.0-12.0, p <0.001).

Conclusions: After the USPSTF recommendation the number of biopsies performed (total and first-time), based on referrals from our catchment area, has decreased. This is likely due to decreased use of prostate specific antigen screening. Although it is encouraging that fewer low risk prostate cancers are being diagnosed, the sudden decrease in the detection rate of Gleason 7-10 prostate cancers is concerning.

Keywords: biopsy; early detection of cancer; prostate; prostatic neoplasms.