"Do not use prostate-specific antigen (PSA)–based screening for prostate cancer."
With these words, the U.S. Preventive Services Task Force (USPSTF) finalized its stance against using this blood test to screen men universally in the United States for prostate cancer.
This firm position is unlikely to end the controversy that ensued after the task force released its draft recommendations in October 2011 ("U.S. Task Force: No PSA Testing for Healthy Men.") Editorials opposing and supporting universal prostate specific antigen (PSA) screening accompany publication early online of the final recommendations in the May 22 issue of Annals of Internal Medicine.
The 16-member task force gave population-based PSA screening a grade D recommendation, after a public comment period yielded no new, overwhelming evidence countering the draft recommendations against universal testing. This means the members believe there is moderate or high certainty that the harms of the intervention are equal to or outweigh the benefits.
"Science shows us the benefit is small and the harms significant," Dr. Virginia A. Moyer, the task force chair, said in an interview.
Fever, blood in the urine, transient urinary difficulties, and moderate-to-severe pain associated with biopsy are potential harms associated with screening cited in the recommendations. Risk for perioperative death, cardiovascular events, urinary incontinence, erectile dysfunction, and bowel dysfunction are some of the harms associated with treatment of prostate cancer.
The recommendation applies to "men in the general U.S. population, regardless of age." The new position replaces the 2008 recommendations, which cited insufficient evidence to support improved health outcomes associated with prostate cancer screening for men younger than 75 years and more conclusive evidence pointing to more harm than benefit for men aged 75 years or older.
The new literature-based recommendations leave room for physicians and patients particularly concerned about risk of prostate cancer to consider individual PSA testing. The USPSTF learned during the public comment period that it needed to emphasize that the recommendations do not preclude such discussions, said Dr. Moyer, professor of pediatrics at Baylor College of Medicine, Houston.
"One of the main things we clarified was ... that this is not a recommendation not to talk to patients about it or not to address the patient’s concerns," she said.
Opponents Step Forward
Coming out against the new recommendations is an ad hoc group of nine oncologists, primary care physicians, and preventive medicine specialists. In an accompanying editorial they argue against curtailment of PSA screening, criticize a lack of specialty physician involvement on the task force, and question the quality of evidence in two large trials heavily weighted in the task force’s decision making: the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial (N. Engl. J. Med. 2009;360:1310-9) and the European Randomized Study for Prostate Cancer (ERSCP) (N. Engl. J. Med. 2012;366:981-90).
"The most important flaws of the PLCO are the greater than 50% ‘contamination’ rate by nonprotocol PSA measurements in the control group, prescreening of 40% of study participants before enrollment in the trial, and the fact that two thirds of patients with abnormal screening tests did not have prompt biopsy," the ad hoc group wrote.
"The study has a known flaw – that a fair number in the control group got screened – which would tend to make the intervention and control groups look more alike," Dr. Moyer acknowledged.
The task force, however, offset this potential bias with inclusion of the European study, she said. The different methodologies used in the two studies provided balance.
The task force does not include urologists or cancer specialists, the ad hoc group also pointed out.
Dr. Moyer said that these specialty physicians were involved in the evidence report initially developed for review by the task force. The members of the task force have "precisely the expertise needed" to advise these doctors on management of asymptomatic men in the primary care setting, she added.
"We are experts in primary care and prevention, and we advise primary care physicians," Dr. Moyer said.
Dr. Otis Brawley Backs Task Force
Backing the task force’s recommendations is Dr. Otis Brawley, chief medical officer of the American Cancer Society. "What many people, doctors as well as lay people, have not truly appreciated is that there are significant harms associated with prostate cancer screening," he said in an interview. "Those harms are seen consistently in every clinical trial that has been done to assess screening."
Dr. Brawley supports individual PSA screening as long as it follows a thorough and balanced informed consent process. "I and the American Cancer Society hold out that there are some people at high risk and some people who are so concerned about prostate cancer that, if they understand the considerable harms and understand that the possibility of benefit is a possibility and not proven, and they want to be screened ... they should be allowed to get screened."