ATLANTA – U.S. Preventive Services Task Force recommendations against using the prostate specific antigen to universally screen men for prostate cancer are unlikely to be last word on the controversial topic– as evidenced by several thousand irked urologists at the annual meeting of the American Urological Association.
Corridors and elevators at the AUA meeting were abuzz with physicians railing against the USPSTF’s finalized recommendation. Scores more piled into a standing-room only auditorium to collectively air their grievances at a town hall meeting convened on PSA screening.
AUA spokesman Dr. Ian Thompson of the University of Texas Health Sciences Center, San Antonio, opened the forum asking: "How many of you do not support the new screening recommendation?" Nearly every member raised a hand – and some added a vocal exclamation point to their reply. Less than 30 hands shot up in support of the USPSTF’s stance against universal PSA screening.
The focal point: whether the USPSTF correctly interpreted the two pivotal trials on which it based its latest recommendations – 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 USPSTF’s 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.
Dr. Fritz Schroder, a primary investigator on the ERSCP, noted that in fact an updated analysis presents a much stronger case for screening than in 2009, when the study was first published. Initially, the study found a 20% decreased risk of prostate cancer mortality, but also a high rate of overdiagnosis. However, it also reflected a relatively short follow-up of 9 years* – not nearly long enough to fully evaluate the effect of screening, said the professor of urology at Erasmus University in Rotterdam, the Netherlands.
"Our subjects were about 63 [years old] when they entered, with an average life expectancy of 15 more years. So we have to wait. We need at least 15 years of data, which we won’t see for several more years. At this point, only 30% of men in both arms have died from anything, and lots of things can happen in the years ahead before we reach that other 70%."
The latest update to ERSCP showed an ever-increasing separation of the mortality curves, with a relative reduction in risk of prostate cancer death of 21% in the PSA screening group. After adjustment, the relative risk reduction was 29% in the screening group. "While the increase [to 29%] is not large, the statistical significance has improved considerably," he said, from a P-value of .04 to a P value of .001. "I believe the argument in favor of screening has more strength, mainly because we now have a 29% reduction in mortality and a highly significant difference."
Ruth Etzioni, Ph.D., agreed. "In any screening trial, the benefit grows over time," said the biostatistician who specialized in modeling prostate cancer outcomes at the Fred Hutchinson Cancer Research Center at the University of Washington, Seattle. "Recognizing that we need to go beyond the data to get numbers relevant for policy making, we must conclude that the picture [in favor of screening], is somewhat more positive than the short-term outcomes suggested."
USPSTF member Timothy J. Wilt did not deviate from his group’s position. He said the task force took the updated evidence into consideration while shaping the final document.
"While there’s no magic number that makes screening beneficial, we do look at the other recommendations we’ve made," with breast cancer and colorectal cancer screening. "For prostate cancer, if there’s any benefit at all, it’s extremely small, saving less that 1 in 1,000 men screened from prostate cancer death, but there are frequent, severe harms," Dr. Wilt said.
The AUA panel agreed that the current PSA test is far from perfect. However, until something better comes along, smarter screening is better than abandoning screening, said Dr. John T. Wei, a urologist at the University of Michigan, Ann Arbor. "It’s clearly helped clinically, but a great number of men also suffer because of it. We need new, better, and more-specific tests so all this harm can be reduced."
Dr. Thompson expressed his own frustration in an interview after the meeting.
"We are just so disappointed that the task force reached this decision. There are foibles with the PSA screen, and we all know that most men will have some abnormality if you look hard enough. But it’s also true that prostate cancer is one of the most common causes of cancer death in men."