Tuesday, May 22, 2012

PSA Screening Benefits Few, Harms Many, Says Panel

A US government-sponsored panel of independent experts that reviews evidence and develops recommendations for preventive clinical services says the harms of PSA-based testing for prostate cancer outweigh the benefits. The recommendation has provoked a strong and angry response from many patient and medical groups.

In a report published early online before print in the 21 May of Annals of Internal Medicine, the US Preventive Services Task Force (USPSTF) writes of PSA-based screening for prostate cancer: "[it] may benefit a small number of men but will result in harm to many others".

The USPSTF is a group of primary care physicians and epidemiologists that is appointed and funded by the US Department of Health and Human Services' Agency for Healthcare Research and Quality (AHRQ). Its recommendations are important because they influence how health policy is shaped and what insurers do. For instance, it is empowered by the Affordable Care Act to decide which screenings Americans receive.

This recommendation is the task force's "final word" on PSA-based testing. It follows a period of public comment after its last published recommendation in 2008, when at the time it concluded there was no evidence to support PSA testing for men over 75.

The task force says it has since then reviewed the evidence published since 2008 and concluded that the harms of PSA-based testing outweigh the benefits, regardless of age. The task force does not take costs into account when developing recommendations: it just weighs health benefits against harms.

The task force posted a draft of this final recommendation for public comment in October 2011. At the time it gave PSA-based screening a "D" grade, which means doctors should not offer the test to their patients because there are more harms than benefits.

Many who commented at the time suggested the "D" be changed to a "C" which says doctors could offer the test to patients who ask for it. But the panel has not changed its draft recommendation, and has stuck to the "D" grade.

According to its Annals of Internal Medicine report, the task force considered two major trials that assessed the life-saving benefits of PSA-based testing in asymptomatic men.

The first trial took place in the US. It did not show that PSA-screening reduce deaths to prostate cancer. The second trial took place in seven European countries and found PSA screening reduced deaths by one death per 1,000 men screened in a subgroup aged 5 to 69 years, mostly in two countries. The other five countries did not find a statistically significant reduction deaths.

The task force reports there is strong evidence that PSA-based screening can be harmful.

Just under 90% of men whose prostate cancer is detected via PSA undergo early treatment, either with surgery, radiation, or androgen deprivation therapy, they write. They say the evidence shows up to 5 out of every 1,000 men die within 1 month of surgery, and between 10 and 70 that survive have to live the rest of their lives with urinary incontinence, erectile and bowel dysfunction.

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