In a public commentary that aired a little over a year ago, I caused quite a stir when I discussed the case of Amy Robach, the then-40-year-old ABC News correspondent who was diagnosed with breast cancer after receiving an on-air mammogram conducted as part of a Good Morning America story about cancer screening programs. Ms. Robach underwent a double mastectomy shortly after her diagnosis and is currently cancer free.
In that commentary, I raised concerns about the message that story presented to the American public about the utility of breast cancer screening programs. Specifically, I worried about the idea, promoted by organizations like the American Cancer Society and Susan G. Komen for the Cure, that all women should undergo screening as early as age 40. Best safe than sorry, right?
But not everyone recommends routine mammography for women starting at the age of 40 — including women like Amy Robach — unless they have a familial history of breast cancer. Those are the cancer guidelines issued in 2009 by the US Preventative Services Task Force, an independent and non-partisan group of healthcare experts. The Preventative Services Task Force concluded that most women should not undergo regular mammography until they are at least 50 years old.
This recommendation may seem counterintuitive. After all, breast cancer is a very serious public health issue. There are few families that it hasn’t touched, including mine. My aunt Kathryn recently passed after battling breast cancer for nearly two decades.
Breast cancer is currently the second leading cause of cancer death among American women. Nearly 250,000 new cases are diagnosed each year, and over 40,000 women die of invasive breast cancer. Moreover, for all of the hype around Angelina Jolie and testing for cancer-related genes like BRCA1, the vast majority of cases of breast cancer are spontaneous; that is, they occur in women with no familial history or genetic predisposition to breast cancer.
For women with no family history of breast cancer, the likelihood of developing it is 1 in 70 for those in their 40’s. That rises to 1 in 35 for those in their 50s, and to 1 in 25 for women in their 60’s. Overall, an American woman has about a 1 in 10 chance of developing breast cancer during her lifetime.
Those are pretty significant odds, so why shouldn’t women be screened annually for breast cancer? Why shouldn’t every woman in America have mammograms as early and as often as possible?
After reviewing decades of epidemiologic data, what the Preventative Services Task Force found was this: unless a woman has a familial history of breast cancer, routine mammograms before age 50 actually yield little benefit. For every 2,000 young women screened for breast cancer by mammography, only a single cancer-related death was prevented.
This is due in part to the fact that rates of breast cancer are lower among women in their 40s, and due to the fact that mammography is a notoriously inaccurate method of screening younger women. The breasts of younger women tend to have more glandular (milk-producing) and connective tissue, while older women have breasts that are more fatty. This glandular and connective tissue is mammographically dense, appearing white on the X-ray film. Abnormalities like tumors also appear white, making them difficult to detect.
As a result, mammography misses an average 20-30 percent of all cases of cancer in younger women (so called false negative results). For women in their 40s with no familial history of breast cancer, non-invasive screening methods — feeling for lumps or looking for other symptoms of breast abnormality — can be as effective at detecting nascent breast cancer as mammography.
Mammography also has a high rate of false positives: findings that look like cancer but are later determined to be benign after additional testing, including invasive biopsies. After just 10 yearly mammograms, over 50% of women will have at least one false positive test result. False positives are particularly common among younger women, again due to that they have mammographically denser breast tissue.
The psychological effects of a false positive test result can be profound. Hearing that you may have cancer can be emotionally devastating, as suggested in recent television commercials produced by the American Cancer Society. The effects of hearing that diagnosis can linger, even after subsequent tests rule out cancer. One study found that a significant number of women who received a false positive result suffered from anxiety and depression. In some women these symptoms continued for years, even after cancer had been definitively ruled out.
In fact, based on all of these data, the American Cancer Society recently changed its breast cancer screening recommendations to be more in line with those of the US Preventative Services Task Force. Previously, the Society recommended annual mammograms starting at age 40. They issued new guidelines this past Tuesday, recommending that women without a familial history breast cancer start having mammograms every year starting at 45, then every other year once they are 54. Other groups like Susan G. Komen for the Cure are still promoting earlier and more frequent screening.
Just like a false positive result, the differing recommendations from Komen, the American Cancer Society and the Preventative Services Task Force are likely to leave women anxious and depressed. Women and their doctors are now left to sort through conflicting messages about cancer screening and decide what is best for them based on their own personal circumstances, medical histories and prevention goals.
And that is the very point that I tried (and failed) to make in my original commentary. Cancer screening and prevention programs should not take a one-size-fits-all approach. The “worried well” might want to undergo frequent screening, so long as their desire to know whether or not they are cancer free is tempered with an understanding and appreciation of the potential harms associated with a false positive or overdiagnosis. Other women might choose to undergo less frequent screening, weighing the benefits of early diagnosis with the risks of mammography.
Screening saves lives, but not everyone needs to be screened. And not everyone needs to be screened early and often.
[This blog entry was originally presented as an oral commentary on Northeast Public Radio on October 22, 2015, and is available on the WAMC website.]