In my last blog, I discussed the rationale behind and evidence supporting the United States Preventive Services Task Force’s (USPSTF) recommendation to discontinue routine PSA screening for prostate cancer. Exceptions might be made in circumstances where men are at high risk. In 2009, the USPSTF found that screening mammography offered no benefit to women in their 40’s. Previously, screening was recommended every other year between ages 40-50. Now it is suggested that women between 50-74 years of age be screened every other year rather than annually. Pushback to all of these recommendations has been “animated” to say the least. Finally, the annual PAP smear for cervical cancer has been challenged. Rather than annual exams, the proposed change is every 3 years.
In her New York Times article of October 29, 2011 entitled: “Considering When It Might Be Best Not to Know About Cancer”, Gina Kolata asks “What changed?” Her conclusion is that new information is now available. In regard to breast cancer, mammography finds the cancer in 138,000 women per year. But between 120,000 to 134,000 have cancers that already are lethal, or cancers that are so indolent they require no treatment. In the same article, the chief medical officer of the American Cancer Society, Dr. Otis Brawley, states the way we look at screening has also changed. “No longer is it just, Can you find the cancer?…..Now it is, Can you find the cancer, and does finding the cancer lead to a decrease in the mortality rate?” Factor in possible harm that can result from screening, e.g, surgical procedures for benign conditions, and increase in cost, resulting in a benefit/risk ratio that is upside down.
While researchers and clinicians are approaching screening from multiple angles, annual mammography has assumed an almost unassailable status from our patients’ point of view. To many, screening is equated with prevention of cancer, which is untrue. Tiring of hearing the unsubstantiated claim that “a mammogram saved my life,” Dr. H. Gilbert Welch and Brittney A. Frankel from Dartmouth conducted an analysis estimating a woman’s 10-year risk of developing breast cancer and her 20-year risk of death. Their calculations included the added value of early detection and benefits from improvements in treatment. It was concluded that of the 60% of women whose breast cancer was detected by mammography, only 3-13% were helped by the test. This amounts to 4,000-18,000 women per year out of a total of 230,000 women diagnosed with the disease. Conversely, of the 138,000 patients found to have breast cancer as a result of screening mammography, 120,000-134,000 are not helped by the test. In turn, these numbers pale when put in the context that 39 million women have mammograms each year in the U.S. So, when they did the numbers, claims that mammography saves lives really are untenable. The paper by Welch and Frankel was published online on October 24, 2011 in the Arch Intern Med.2011.476.
For abstract, click here.
I agree with my colleagues that some women are helped by screening but the numbers are very low. Also, the premise that early diagnosis saves lives has been somewhat diminished by improvements in treatment of aggressive and even advanced cancers. Mammography has certainly improved our ability to diagnose breast cancers earlier as reflected by the marked increase in incidence of carcinoma in situ, i.e., pre-invasive cancer. And these are not lethal cancers. Do these facts justify the $5 billion spent on mammograms annually? I think not. But the reality is until these recommendations become standard of care, I doubt that many physicians would be brave enough to adopt these as policy in our litigious society. That’s the sad truth.