medwireNews: Prostate cancer has undergone “reverse migration” away from indolent disease and toward more aggressive presentation in the USA following recommendations against prostate-specific antigen screening, say researchers.
In 2012, the US Preventive Services Task Force (USPSTF) made a formal Grade D recommendation against prostate-specific antigen screening for all men in response to concerns about screening efficacy and overdetection and treatment of indolent disease.
To determine the impact of this recommendation, Brandon Mahal (Harvard Medical School, Boston, Massachusetts, USA) and colleagues used contemporary, population-based data from the SEER database to calculate trends in the incidence of prostate cancer in men older than 50 years from 2010 to 2015. They took into account disease stage at diagnosis, age group, and National Comprehensive Cancer Network (NCCN)-defined risk groups.
The team found significant decreases in the annual incidence of localized prostate cancer, from 195.4 to 131.9 per 100,000 persons in men aged 50–74 years, and from 189.0 to 123.4 per 100,000 persons in those aged 75 years and older.
This decrease in localized prostate cancer incidence was seen for both NCCN low-risk and unfavorable (intermediate/high)-risk sub-groups, dropping from a respective 60.6 to 31.4 per 100,000 persons and 104.2 to 84.3 per 100,000 persons among 50–74-year olds, and from 26.1 to 11.6 and 134.5 to 94.7 per 100,000 persons among men aged 75 years and older.
The largest relative year-by-year decline in the incidence of localized disease occurred between 2011 and 2012, regardless of age or risk group, the researchers say.
By contrast, the incidence of metastatic disease significantly increased from 6.2 to 7.1 per 100,000 persons in men aged 50–74 years and from 16.8 to 22.6 per 100,000 persons in the older age group.
The researchers also note that for men considered to be at low risk the annual incidence of localized prostate cancer significantly decreased year-on-year, whereas for those considered to have an unfavorable-risk it declined between 2011 and 2012 before increasing again between 2014 and 2015.
Mahal and colleagues comment: “The declines in low-risk disease were a goal of USPSTF recommendations against screening. However, many men with potentially curable disease may present with more advanced and difficult-to-cure disease later on, as suggested by the slow increases in metastatic disease and increasing incidence of unfavorable-risk disease between 2014 and 2015.”
In an accompanying editorial, Shreyas Joshi and Christopher Filson (both from Emory University School of Medicine, Atlanta, Georgia, USA) say: “Decreasing overdiagnosis of low-risk disease was the intended outcome of the recommendation. Although it is difficult to determine how many men with low-risk prostate cancer were spared a misdiagnosis, it is likely that many men in this category will live full, healthy lives without having learned of the burdensome finding.
“However, it appears that the USPSTF’s recommendation may have been too blunt of a hammer; the policy also affected men who were destined to develop more advanced disease.”
By Catherine Booth
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