Variation in prostate cancer screening rates associated with subsequent metastatic prostate cancer incidence

1. A retrospective analysis demonstrated that prostate-specific antigen (PSA) screening has overall declined in popularity in recent years.

2. Health centers with higher rates of PSA screening tended to have lower rates of metastatic prostate cancer diagnosis.

Level of Evidence Rating: 2 (Good)

Study Rundown: Prostate cancer is one of the most common malignancies, although unpredictable tumor biology makes it difficult to define screening guidelines for the average-risk population. The decision to monitor prostate-specific antigen (PSA) levels is thus individualized based on a patient’s risk factors for the disease and their goals of care. Society guidelines have varied with time as new evidence emerges about the etiology and course of prostate cancer. As such, Bryant et al. sought to determine how trends in PSA screening affected the rate of metastatic prostate cancer diagnoses at the population level.

Data from 4,678,412 patients were included in this study.  There was an overall decline in the rate of PSA screening over the study period by approximately 10% between 2005 to 2019. The rate of prostate biopsy decreased accordingly as well. The age-adjusted incidence rate of prostate cancer diagnosis decreased in the first part of the study period up until 2014 and was relatively stable thereafter. Concomitantly, the rate of metastatic prostate cancer diagnosis increased over the study period. The year with the lowest rate of metastatic prostate cancer was also the year with the highest rate of PSA screening (2008).

This study demonstrated that there may be an inverse relationship between PSA screening rates and prostate cancer mortality amongst the general population. A primary strength of this study was the large sample size and the longitudinal follow-up. However, these results should be interpreted with caution given the retrospective nature of this study and the many personal considerations that may factor into a patient’s decision as to whether they should pursue PSA screening.

Click here to read this study in JAMA Oncology

Relevant reading: PSA screening in high-risk groups: what are the changes in benefit and harm?

In-Depth: [retrospective cohort]: Data for this study were ascertained from the Veterans Affairs Corporate Warehouse, which accounts for the medical records of all United States army veterans from designated facilities. Records were reviewed from 2005 through to 2019. The exposure of interest was the rate of PSA screening between 2005 and 2014, calculated as the number of males over 40 who underwent PSA testing out of all males over 40 receiving healthcare at a given Veterans Affairs Health Center in a year. The primary outcome was the rate of metastatic prostate cancer diagnosis as defined by Gleason score or pathology report definitions.

The PSA screening rate in 2005 was 47.2%, and 37.0% in 2019. PSA screening peaked at 50.8% of the cohort in 2008. The rate of non-screening, defined as patients who had not undergone a PSA test within 3 years of the index date, increased from 20.9% in 2005 to 33.2% in 2019. The incidence rate of metastatic prostate cancer in 2005 was 5.2 per 100,000 men and 7.9 per 100,000 men in 2019. The lowest incidence rate reported was 4.6 per 100,000 men in 2008. Statistical analysis demonstrated that facility-level PSA screening rates did seem to affect rates of metastatic prostate cancer diagnosis: an incidence rate ratio of 0.91 for the risk of metastatic prostate cancer with each 10% increase in the rate of screening was identified (95% confidence interval 0.87-0.96). Other factors associated with increased risk of metastatic disease included Black patients, patients older than 70 and those living in the Pacific region.

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