“There is value in screening, but it comes with a price,” says Welch, who pointed to clinical trial data indicating that between 21% and 49% of women undergoing mammography screening over 10 years are at risk for false-positive results, which can lead to further, more aggressive and costly testing. “The real money isn't spent on screening, but on the follow-up testing,” Welch adds. “We have to be really careful to ask the question: Does this lead to healthier patients and a healthier society?”
Screening costs are hardly minuscule, however. Medicare dished out $546 million in physician and hospital outpatient-services payments in 2008 to cover screening mammograms, according to CMS figures. The agency spent $169.6 million on colonoscopies, which screen for colon cancer, and $63.3 million on prostate cancer screenings—which includes costs for both digital rectal exams and the prostate-specific antigen, or PSA, test.
But providers argue that decisions about which screening tests are covered by payers are often the result of political and financial pressures rather than available science.
For example, while Medicare covers annual prostate cancer screening, a 17-year, 10-center study conducted by the National Cancer Institute and published in the New England Journal of Medicine in March 2009 found that screening for the PSA led to more diagnosis of the disease but did nothing to reduce the number of deaths caused by prostate cancer.
It found that men diagnosed through PSA screening with early-stage prostate cancer underwent the same level of aggressive treatment, which can include surgery and radiation therapy, as men with more advanced cancers but had no difference in survival rates.
Conversely, CMS officials decided in May 2009 that Medicare would not cover CT colonography screening—also called virtual colonoscopy—saying evidence was inadequate to conclude the imaging procedure was an appropriate screening test for colon cancer. In studies, the test, which is less invasive than traditional colonoscopy, was able to identify 90% of precancerous polyps found by colonoscopy when the polyps were 10 millimeters or larger. Removal of polyps has been proven to prevent development of colon cancer in patients, says Otis Brawley, M.D., chief medical officer for the American Cancer Society and a professor of hematology, oncology and medicine at Atlanta's Emory University medical school.
Advocacy groups argue that CT colonography has the potential to save more lives than traditional colonoscopy because more patients are likely to have the less-invasive annual screenings. “The question is not does it work, but costs,” says Brawley, who believes the agency's coverage decision was flawed.
But the Medicare Payment Advisory Commission in its advisory memo to the CMS said it had little confidence, based on evidence, that the test would increase screening rates. In a vote, the commission also said that while it was somewhat confident that CT colonography could provide similar health outcomes as traditional colonoscopy, it was doubtful that colonography would have a similar ratio of cost per life years saved as that of a colonoscopy.
Reimbursement rates differ, and it is hard to determine whether CT colonography or traditional colonoscopy is the more expensive procedure. Nevertheless, MedPAC found that colonography isn't cost-effective because when polyps are found, patients have to undergo a second procedure to remove growths that could have been addressed through a single colonoscopy procedure.
“MedPAC did say that if you can increase the number of people being screened for colorectal cancer, CT colonography would be cost-effective,” says Judy Yee, M.D., a Veteran's Affairs Department radiologist and chair of the American College of Radiology colon cancer committee.
Healthcare policymakers are split over the issue of disease screening for a variety of reasons, including questions about its overall usefulness.
“Sometimes the assumption is made that just because you can better detect it means you'll be able to do something of value for that population,” says Karen Schoelles, M.D., director of the Evidence-based Practice Center at the ECRI Institute, a comparative-effectiveness research organization.
Schoelles notes that one of the challenges of disease screening is that, even when you have tests that accurately detect and predict conditions, healthcare providers need to consider whether screening for a particular disease meets several usefulness criteria laid out by health-services researchers P.S. Frame and S.J. Carlson in the 1975 article series “A critical review of periodic health screening using specific screening criteria.” The criteria are considered the gold standard for physicians considering screening referrals. Among the requirements are the suggestions that an effective method of treatment must be available for the disease, and that the condition have an asymptomatic phase during which detection and treatment significantly reduce illness severity and possibility of death.
The authors also said the occurrence of a particular condition or disease needs to be sufficient enough to justify the cost of screening.
But as the U.S. Preventive Services Task Force members discovered, cost as a factor of screening criteria nearly always produces the type of sharp rebuke that came in response to its new breast-cancer screening recommendations.
Reviewing nine years of clinical-trial data on mammography screening, the task force last November concluded that while studies show annual screening reduced breast-cancer death rates by 15% in women aged 39 to 49, it also resulted in more false-positive findings and overdiagnosis of existing breast cancers among women in that age group than those aged 50 and older.
Young women, as a result, are more likely to undergo unnecessary and costly biopsies and additional imaging tests, the task force found. The group also noted that for every one breast-cancer death prevented among 40- to 49-year-old women, 1,904 patients are screened.
By comparison, one death is prevented for every 1,339 women ages 50 to 59 and 377 women ages 60 to 69 who are screened.
In response to such findings, the task force advised women with no predisposition to developing breast cancer to delay mammography screening until age 50. It also suggested women aged 50 to 74 only receive mammograms every two years. “If the goal of a national screening program is to reduce mortality in the most efficient manner, then programs that screen biennially from age 50 years to age 69, 74 or 79 years are among the most efficient on the basis of the ratio of benefits to the number of screening examinations,” wrote the task force in its analysis.