Seek proof before you recommend clinical preventive services
Chalk up two for the snails.
In his Scientific Assembly lecture on clinical preventive medicine, Paul S. Frame, MD, a member of the US Preventive Services Task Force, explained the schools of thought regarding preventive interventions.
Evangelists believe the harms of waiting for evidence to support a given preventive screening or treatment outweigh the harms of using it.
Snails say that preventive interventions shouldn't be routinely recommended until sufficient evidence is available to show that net benefits outweigh the harms.
The rural Rochester, NY, FP stressed that neither approach is necessarily better or right in every case. "However, there are clear precedents where making recommendations before the evidence was in got us in some trouble," he said.
For example, in 1948 doctors first began recommending annual chest x-rays to screen for lung cancer, said Dr. Frame. In 1971, randomized trials were conducted to determine whether x-rays affected outcomes. By 1980, evidence showed chest x-rays didn't reduce mortality, and doctors quit recommending them as a preventive measure.
Dr. Frame emphasized the ethical difference between preventive and regular interventions: "In contrast to the usual symptomatic patient, the asymptomatic patient feels fine. The physician is suggesting procedures or lifestyle interventions that have costs and adverse effects as well as benefits. In this situation, it is necessary to have substantial proof that benefits outweigh the risks."
Providing good preventive care to all patients is a huge job, so Dr. Frame said he concentrates on screenings and treatments with documented evidence of effectiveness. He cited two examples of common screenings that lack such evidence:
Prostate screenings
Dr. Frame said he doesn't routinely recommend digital exams or prostate-specific antigen (PSA) testing for asymptomatic men because the treatments for prostate cancer don't save enough lives to justify the procedures.
The public has the perception that all prostate cancer will lead to death unless it's treated and eradicated. That's not true, said Dr. Frame. Although 46 percent of men older than 70 have prostate cancer, more men will die with it than from it, he said.
The US Preventive Services Task Force classifies both digital rectal exams and PSA testing as category "D," which means a fair amount of evidence exists to justify excluding the procedures from the periodic health exam.
Mammograms for women under 50
Studies show that mammograms for women ages 50-69 result in a 25-30 percent reduction in mortality. For healthy women ages 40-49, however, the data don't show sufficient evidence of a benefit, said Dr. Frame. Providing a "best case scenario" for mammography among women 40-49, he said: The risk of dying from breast cancer that develops in the 40s is one out of 190 women; if mammography reduces mortality by 20 percent, 950 women in that age group need to be screened to save one life; 30 percent will have false positive mammograms, and 5-10 percent may require biopsies.
The US Preventive Services Task Force classifies mammography for women 40-49 as a "C," which means insufficient evidence is available to either include or exclude it in the periodic health exam.
Dr. Frame encouraged FPs to talk to patients about preventive care and to provide preventive services, such as immunizations or smoking cessation counseling, at every patient visit. Individualize health maintenance programs to each patient, using interventions that address their personal health practices.
- FP Report is published by the AAFP News Department.