Benefits of PSA screens revised downward.
Researchers applied complex modeling to the European Randomized Study of Screening for Prostate Cancer (ERSPC), which reported screening cuts prostate cancer mortality by 29%.
The results indicate that screening saves lives but found that the benefit was undercut by long-term effects of overdiagnosis and overtreatment.
The new analysis calculates the ER-SPC results in quality-adjusted life-years (QALYs), a measure the researchers based on health states ranging from "death or worst imaginable health" to full health and on treatment-related complications such as urinary incontinence, bowel dysfunction, and sexual dysfunction.
"Our model predicts that there would be nine fewer prostate cancer deaths and 73 life-years gained over the lifetime of 1,000 men who underwent annual screening between the ages of 55 and 69 years," write Dr. Eveline A.M. Heijnsdijk of Erasmus Medical Center, Rotterdam, the Netherlands, and her coauthors.
"The harms caused by ... such screening would be the overdiagnosis and overtreatment of 45 cases and the loss of 1,134 life-years free of prostate cancer (i.e., lead-time years).
After adjustment of the number of life-years gained from screening by consideration of quality-of-life effects, 56 QALYs would be gained. That is a 23% reduction from the predicted number of life-years gained."
Extending screening to men aged 74 years would increase the number of unadjusted life-years gained to 82, but QALYs would stay the same at 56, according to the authors (N. Engl. J. Med. 2012; 367: 595-605 [doi: 10.1056/NEJ-Moa1201637]).
The U.S. Preventive Services Task Force (USPSTF) set off a furor in May when it took a stand against PSA screening for prostate cancer in healthy men, arguing that the harms outweigh the benefits.
Debate has centered on interpretation of data from the ERSPC trial (N. Engl. J. Med. 2012; 366: 981-90) and the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial (N. Engl. J. Med. 2009; 360: 1310-9), with proponents of universal screening arguing that it saves lives.
"The predicted adjustment for quality of life is due to the long-term side effects from treatment. Men in whom cancer has been overdiagnosed and those in whom cancer has not been overdiagnosed will live many years with the adverse effects of treatment," they write.
Dr. Heijnsdijk and her coauthors did not take a stand on screening, proposing instead that more long-term data are needed along with more research and more modeling to calculate cost-effectiveness.
"It is essential to await longer follow-up data from the ERSPC, as well as longer-term data on how treatment and active surveillance affect long-term quality of life, before more general recommendations can be made regarding mass PSA screening," they conclude.
Major Finding: Screening 1,000 men aged 55-69 years would save 9 men from prostate cancer with a gain of 73 unadjusted life-years but only 56 quality-adjusted life-years (QALYs).
Data Source: Investigators analyzed data from the European Randomized Study of Screening for Prostate Cancer (ERSPC).
Disclosures: The analysis was supported by grants from the Netherlands Organization for Health Research and Development, Europe Against Cancer, and the European Union; agencies or health authorities in participating countries; and by unconditional grants from Beckman Coulter. Dr. Heijnsdijk disclosed receiving consulting fees from Beckman Coulter, and her coauthors reported relationships with various companies.
VIEW ON THE NEWS
More Data Needed to Draw the Line
The PSA screening controversy "is less about the evidence and more about where to draw the line," Dr. Harold C. Sox comments, suggesting in an accompanying editorial that the study shows a way to resolve the dispute.
By using the same measure--quality-adjusted life-years--to quantify harms and benefits, the authors address "the apples and oranges problem," he writes. "They find that PSA screening may reduce or increase quality-adjusted survival, depending on the value that a man places on the health states that he may face in later life."
Dr. Sox sees two important implications of the analysis. "It reminds us in stark terms that decisions about PSA screening depend in part on how the patient feels about the downstream consequences of screening, a fact that is easily forgotten in the stress of daily office practice. More important, however, the study is a model for developing the evidence base for practice guidelines," he writes (N. Engl. J. Med. 2012 Aug. 16; 367: 669-71).
Data is needed on the quality weight (called a utility) that patients assign to health states.
For now, "guidelines should avoid recommending for or against PSA screening. Instead, they should recommend shared decision making, which guarantees tht the decision will take into account patients' utilities for their potential future health states.
In the future, a decision-support system incorporating the authors' model could provide patients with individualized assistance with the decision regarding PSA screening."
DR. SOX, a professor of medicine, is with the Dartmouth Institute for Health Policy and Clinical Practice at Dartmouth University in Hanover, N.H. He is a former chair of the U.S. Preventive Services Task Force and serves on the board of the Informed Medical Decisions Foundation, which makes decision aids for screening.
BY JANE BALODOP MACNEIL
FROM THE NEW ENGLAND JOURNAL OF MEDICINE
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|Author:||MacNeil, Jane Salodof|
|Publication:||Internal Medicine News|
|Article Type:||Clinical report|
|Date:||Nov 1, 2012|
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