Why Cancer Screening May Not Save Your Life

Nothing about health care makes people as frantic, upset, and downright furious as being told that cancer screening is not likely to save their lives—something I learn every time I write about it. So I wouldn't want to be the poor people who handle the switchboard and e-mail at the American Cancer Society: as The New York Timesreported today, the ACS is preparing to modify its assessment of the value of some cancer screening because, as experts have known for years, it has not proved to be the lifesaver that everyone hoped and assumed. (Click here to follow Sharon Begley)

We are approaching a perfect storm on the fraught topic of screening. In this corner, more and more studies are casting doubt on the value of screening (which means running tests, often X-rays or other imaging, on people with no symptoms of disease). In the opposite corner, the debate over health-care reform has raised the dreaded specter of rationing. Any bets on whether people will believe that decreasing patients' access to screening, or decreasing insurance (especially Medicare) coverage of it, will be seen not as good medicine but as cruel and dangerous policy? Death panels indeed.

Some hint about how patients will react to any attempt to place screening on a solid scientific footing came last week. About 120 patients, doctors, and patient advocates rallied on Capitol Hill to protest provisions in the House's health-care reform bill and in the Baucus bill in the Senate that would decrease how much Medicare reimburses radiologists and others for imaging, such as MRIs and CT scans. In a letter to President Obama and Kathleen Sebelius, secretary of health and human services, 20 patient groups argued that "further deep reductions in Medicare reimbursements for diagnostic imaging would jeopardize the health of America's seniors…Limiting access to vital advanced imaging services will counteract efforts to identify and treat disease early."

If only it were that simple, or true. Unfortunately, in the case of cancer screening—again, the term refers to imaging in people with no symptoms (such as, in breast cancer, nipple discharge)—this has not been shown. As I wrote last spring, "finding a tumor when it is small should mean a better chance that surgery, radiation, and/or chemotherapy will eradicate it, allowing you to live until something else kills you. Early detection should produce clear, unquestionable benefits. Yet it doesn't. Not the PSA, not early detection of lung or testicular or pancreatic cancer, or glioblastomas, a type of brain cancer. Even mammography is iffy."

The evidence on this is abundant, but let me mention the latest. In a commentary in the current issue of The Journal of the American Medical Association, physicians urge a "rethinking" of screening for breast and prostate cancer. The basic problem, they note, is that since screening for these cancers became widespread with mammograms and the PSA test, the number of early cancers detected has gone up, but the number of advanced cancers has not. If screening worked, in the sense of catching life-threatening cancers early, then many advanced cancers would have moved into the former category—that is, been found and treated before they grew or spread. That this has not happened suggests that screening is finding many, many nonthreatening tumors that, left on their own, might never have advanced, let alone posed a threat to someone's life. In other words, the JAMA authors write, "screening may be increasing the burden of low-risk cancers without significantly reducing the burden of more aggressively growing cancers and therefore not resulting in the anticipated reduction in cancer mortality." Translation: screening is finding lots of tumors that doctors wind up biopsying and treating, perhaps unnecessarily. It is not saving lives.

"The benefit [of cancer screening] is not nearly as much as we hoped and comes at the cost of overdiagnosis and overtreatment," said coauthor Laura Esserman of the University of California, San Francisco, Carol Franc Buck Breast Care Center.

How unwelcome is this message? It is especially ironic that lung-cancer advocates are up in arms about the prospect of less access to imaging. "We know that early disease detection dramatically improves the chances of survival," said Sheila Ross, special counsel of the Lung Cancer Alliance and two-time lung-cancer survivor, said in a statement released by a PR firm working for the Access to Medical Imaging Coalition, which represents patient groups as well as physicians and companies that perform imaging or sell imaging equipment. The irony is this: screening for lung cancer has been an abysmal failure in terms of saving lives. And the one study that suggested it did has been engulfed in charges of ethics violations.

As for the ACS, it issued a statement saying that "the advantages of screening for some cancers have been overstated," but that it continues to endorse screening for breast, colon, and cervical cancers. The latter two are fairly uncontroversial (colonoscopy can detect polyps before they become malignant, and Pap smears detect precancerous cervical lesions). Mammography is on shakier ground, since the clinical trials that showed it to reduce the risk of dying of breast cancer were done before widespread use of effective new adjuvant treatments—that is, chemotherapy and radiation. The ACS does acknowledge that mammography "in some cases finds disease that does not need treatment." It hasn't recommended the PSA test for years, however.

The sad fact that lots of imaging does not unambiguously keep people healthy goes beyond cancer screening. Overuse of MRIs is especially rife in cases of back pain, as Nortin Hadler of the University of North Carolina at Chapel Hill details in his brilliant book Stabbed in the Back: Confronting Back Pain in an Overtreated Society(and as he explained in a JAMA paper two years ago). Worse, patients with low-back pain (the fifth-most common reason Americans go to a doctor) are more likely to have surgery if they're in an area with lots of MRI centers, scientists from Stanford University School of Medicine reported last week in the online edition of Health Affairs. And what's wrong with that? Surgery is notorious for not helping with back pain any more than, say, bed rest and exercise (and even sugar pills). But it poses a risk of much worse complications. "The worry is that many people will not benefit from the surgery, so heading in this direction [of expanding use of and access to MRIs] is concerning," said coauthor Laurence Baker of Stanford.

Just to make the rationing fearmongers even more hysterical: clinical guidelines say that patients with lower-back pain should wait four weeks before getting an MRI (which typically costs $1,500), since in most patients—yes, I said most—the pain goes away on its own. I can see the headlines now—what is this, Canada??!!—if doctors actually put those guidelines into widespread practice. As it is now, however, "the net result is increased risks of unnecessary surgery for patients and increased costs for everybody else," said John Birkmeyer, professor of surgery at the University of Michigan.

What effect will such scientific findings have on patients and doctors? "I don't think the country is yet prepared to hear such arguments," Hadler told me in an e-mail interview. "Screening has become an entitlement; to not [get] screening is un-American even when the screening test is inaccurate, invalid and offers no benefit."