Changes in Prostate Cancer Presentation Following the 2012 USPSTF Screening Statement: Observational Study in a Multispecialty Group Practice

In this retrospective study conducted at Kaiser Permanente Northern California (KPNC) from 2010 to 2015, we wished to better understand the impact of the 2012 U.S. Preventive Services Task Force (USPSTF) Prostate Cancer Screening Statement which gave a “D grade” for prostate-specific antigen (PSA) screening, essentially saying no one should be screened. Since screening is most commonly done in the primary care doctor’s office, and since primary care doctors tend to follow USPSTF guidelines, we felt it critical to conduct this observational study to better understand its consequences.

In order to calculate rates, an accurate denominator is needed. Since KPNC is a “closed system”, we used all screen-eligible men according to our internal National Kaiser Permanente Prostate Cancer Screening Guidelines (African American men ages 45-69, all other men ages 50-69) as our denominator. Of note, our internal guidelines did not significantly change over the study period, essentially suggesting shared decision-making for screen eligible men. However, as demonstrated in our study we saw a large drop in screening and biopsy rates following the 2012 USPSTF statement. We observed a decline in overall prostate cancer detection rates but this was at the expense of an increase in metastatic cancer rates. We acknowledge that some of this decline in overall cancer detection might be beneficial, as some of these cancers were likely indolent (we did not quantify this outcome in this study, but will be addressed in future work). For every 25 fewer cancers detected, one metastatic cancer was diagnosed.

While one cannot prove causality in this observational study, we attempted to control for confounders that might influence screening and cancer rates such as age, race, BMI, comorbidities, smoking status, and primary care utilization. These demographics were similar between the pre-guideline and post-guideline periods.

While the optimal detection strategy needs to be defined, it is clear that abandoning screening results in more men with metastatic prostate cancer is a uniformly fatal outcome. Fortunately, in 2018, the USPSTF upgraded its screening statement to “C” so that more shared decision-making may take place. We look forward to seeing the impact of this change in the future.

Written by: Joseph Presti, Jr., MD, Regional Leader of Urologic Oncology Surgery, Kaiser Permanente Northern California, Oakland, California

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