Prostate-specific antigen screening helps prostate cancer detection

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Controversy surrounding prostate cancer screening is due to the harm from overdetection and overtreatment that can outweigh patient quality of life.
Controversy surrounding prostate cancer screening is due to the harm from overdetection and overtreatment that can outweigh patient quality of life.

More cases of prostate cancer are detected in patients who are randomized to receive single prostate-specific antigen (PSA) screening than patients who received standard practice without screening, according to a study published in JAMA.

Richard M Martin, PhD, of the Department of Population Health Sciences, at Bristol Medical School, University of Bristol in England, and associates conducted a randomized clinical study of men between the ages of 50 and 69 to determine the impact of PSA screening on prostate cancer detection and mortality.

The entire cohort included 419,582 men: 189,386 were screened for prostate cancer using the PSA screening methods and 219,439 were control participants.

The primary outcome was prostate cancer-related mortality at a median follow-up of 10 years. The secondary outcomes included diagnostic cancer stage and Gleason grade, all-cause mortality, and predicted underlying effects of PSA screening attendance. Gleason grade was defined as a score of detected prostate cancer varying from 2 to 10; the higher score was associated with a poorer diagnosis.

From the initial group, 98% remained in the clinical trial. Of participants in the case group (intervention cohort), 40% went to the PSA testing clinic, 36% had blood samples drawn for PSA testing, and 34% (n=64,436) had usable PSA test results.

Eleven percent of patients with valid test results had PSA levels ranging from 3 ng/mL to 19.9 ng/mL (85% of these patients has a prostate biopsy). The investigators reported 549 prostate cancer-related deaths in the case group and 647 prostate cancer-related deaths in the control group (rate ratio [RR], 0.96).

More patients were diagnosed with prostate cancer in the PSA testing group (4.3%) than in the control group (3.6%) (RR, 1.19), and more prostate cancer tumors with Gleason grades 6 or below were reported in the case group (1.7%) rather than in the control group (1.1%); the rate ratios of all-cause mortality for the case and control groups were 0.99 and 0.93, respectively.

“Among practices randomized to a single PSA screening intervention vs standard practice without screening, there was no significant difference in prostate cancer mortality after a median follow-up of 10 years but the detection of low-risk prostate cancer cases increased,” reported the authors. “Although longer-term follow-up is under way, the findings do not support single PSA testing for population-based screening.”

Reference

  1. Martin RM, Donovan JL, Turner EL, et al. Effect of a low-intensity PSA-based screening intervention on prostate cancer mortality: The CAP randomized clinical trial. JAMA. 2018 March 6. doi:10.1001/jama.2018.0154
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