Do the Benefits of Regular PSA Screening Outweigh Harms?
A team of investigators has found that the U.S. Preventive Task Force (USPSTF) recommendation against regular screening for prostate cancer may help reduce the overdiagnosis and overtreatment of low-risk prostate cancer, but may also contribute to missed diagnoses in men who may benefit from the treatment.
In 2011, the USPSTF determined that the drawbacks of regular prostate-specific antigen (PSA) screening outstripped the benefits, and began recommending against regular screening for prostate cancer. In an effort to evaluate the impact the new guideline has had since being introduced in 2011, the authors analyzed screening practices among urologists and primary care providers, and the incidence of prostate cancer to identify changes in the number and distribution of new prostate cancer diagnoses in the United States. Cancers diagnosed in the National Cancer Database between January 2010 and December 2012 were studied in order to assess monthly trends in new prostate cancer diagnoses both before and after the guidelines were issued.
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The number of overall prostate cancer diagnoses dropped by more than 12% across all subgroups of age, comorbidity, race, income, and insurance in the month after the guidelines were issued. Diagnoses continued to decline in the next 11 months as well, according to the authors, who note that the number of low-, intermediate-, and high-risk prostate cancers all went down in the first 12 months after the recommendations changed. The number of new diagnoses of non-localized prostate cancer remained steady. At 12 months after the guidelines were issued, new low-risk cancer diagnoses fell by 37.9%, and continued to decrease at a faster rate than other disease risk grades.
The investigators also found, however, that diagnoses of intermediate-risk and high-risk prostate cancer dropped by 28.1% and 23.1% in that time, respectively.
Study co-author David Penson, MD, MPH, professor and chair in the department of urologic surgery at Vanderbilt University Medical Center, notes that the findings “don’t imply that the USPSTF recommendation increases the risk of prostate cancer.”
The study essentially shows that “the recommendation has resulted in a decrease in the incidence of prostate cancer across all risk groups.”
While this could be interpreted positively in the low-risk patients—who are at greatest risk for over diagnosis and over treatment—the fact that the incidence of high-risk disease has dropped as well as a result of the recommendation is “very worrisome,” says Penson.
“These are the patients with the most aggressive forms of prostate cancer and are at lowest risk for over diagnosis and over treatment. Effectively, they are the ones who would garner the most benefit from early detection and treatment,” he says, adding that “this statement is supported by the results of the PIVOT study and the SPCG-4 study. The USPSTF recommendation has effectively been harmful to these patients.”
While the USPSTF has advised against prostate cancer screening, other organizations such as the American Cancer Society and the American Urological Association recommend shared decision-making around prostate cancer screening, says Penson, who urges primary care practitioners to “explain the pros and cons of prostate cancer screening in a fair and objective manner, and let the patient make his or her own decision.”
—Mark McGraw
Reference
Barocas D, Mallin K, et al. The effect of the USPSTF grade D recommendation against screening for prostate cancer on incident prostate cancer diagnoses in the United States. J Urol. 2015.