Screening for prostate cancer, which typically starts with a prostate specific antigen (PSA) test, has a complicated history. The inherent lack of specificity of PSA for detecting aggressive cancer and the concerns over the potential negative effects in identifying and treating indolent cancers have resulted in several changes to screening guidelines. In 2012, PSA-based screening for prostate cancer was downgraded to a “D” (“Discourage the use of this service”) by the United States Preventive Services Task Force (USPSTF), one of the most influential groups for screening guidelines.¹ Following this change in guidelines, researchers found a decrease in the rate of PSA testing² and a decrease in the rate of overall prostate cancer detection, as well as an increase in the incidence of metastatic prostate cancer.³

The incidence and natural history of prostate cancer vary among races. Black men typically have a higher incidence and mortality compared to White men, while rates among Asian men are lower still. We wished to investigate possible racial disparities that may have arisen (or remained) after the USPSTF statement.⁴

We performed a longitudinal retrospective cohort study using our data at Kaiser Permanente Northern California.⁴ As an integrated health plan, we were uniquely situated to observe the longitudinal relationship between changes in screening rates and outcomes. Since our study population derived from a large, community-based, multispecialty group practice, we could identify a true denominator for all rate calculations by accounting for all eligible individuals in the system. Moreover, in our open access system, potential financial barriers to screening and additional testing were minimized.

Figure. PSA screening and metastatic cancer rates. Solid lines are screening rates and dashed lines are metastatic rates. Starting in 2012, screening rates declined and metastatic cancer detection rates rose.

To examine changes before and after the 2012 USPSTF guidelines, we defined 2006–2011 as the “pre-period” and 2014–2017 the “post-period.” In comparing the pre-period to the post-period, there was a statistically significant decrease in PSA screening rates for all races. This reduction in screening was mirrored by a reduction in the rates of biopsy and all-cancer detection. With the reduction of both biopsy and cancer detection rates, the original intent of the USPSTF statement was accomplished. However, at the same time, the metastatic prostate cancer detection incidence rates increased across all races. Of note, the PSA screening rate remained the highest for Asian men, even though they had the lowest cancer detection rate. At the same time, Black and White men had lower but similar screening rates, yet Black men had the highest cancer-detection rate (see figure). Moreover, the change in the rate of metastatic prostate cancer increased the most for Black men.

Given the understanding of the natural history of prostate cancer, it was surprising to see an increase in metastatic rates so quickly following the change in the USPSTF recommendation, but this trend has nonetheless been observed in other studies.⁵ We are particularly concerned that if the trend continued a few more years, the difference in the slope of increase of metastatic cancer rate for Black men would continue to widen the disparity.

As there was another change in the USPSTF guidelines in 2018, upgrading PSA-based screening to a “C” recommendation (“Offer or provide this service for selected patients depending on individual circumstances”), we may see a reduction in the metastatic cancer rate, but once again there are no race-specific guidelines to try and address the disparities that have remained since 2012. We believe that organizations and bodies like the USPSTF should consider guidelines that directly address high-risk populations such as Black men and those with a family history of prostate cancer. While we recognize that we do not have data from a randomized screening trial to support this assertion, we feel that observational studies such as ours provide ample evidence to support this change. Without practice change, these disparities will likely persist.