About once a year on average, I seem to create a bit of a stir with a commentary on breast cancer and screening guidelines. In those commentaries, I sometimes question the message that is given to American women about the utility of breast cancer screening programs. In the weeks that follow, both my email and my answering machine tend to fill up with people suggesting that I am wrong, sharing personal tales of invasive cancers that were detected only because of screening, and sometimes (although very rarely) hoping that a relative of mine is stricken with the disease.
Given this, let me start by saying that I take the topic of breast cancer very seriously. Breast cancer is one of the leading causes of cancer death among American women, second only to lung cancer. Nearly 250,000 new cases are detected each year in the United States, and over 40,000 women die annually from the disease.
All told, nearly 1 in 8 American women will be diagnosed with breast cancer during their lifetime, most of who have no familial history or genetic predisposition to the disease. Few families thus remain untouched by breast cancer, including mine. My aunt Kathryn finally succumbed to the disease in 2015 after battling it for nearly two decades.
Breast cancer is a public health crisis and one that deserves a strong, concerted and well-reasoned response. The problem, however, is that current public health messages about breast cancer screening and treatment are disjointed at best and dangerous at worst. Currently, different professional organizations in the US offer differing and often contradictory advice about if, how and when women should be screened.
For instance, the American College of Radiology takes a very aggressive stance on screening and treatment, recommending that all women get annual mammograms starting at the age of 40. Private organizations like the Susan G. Komen for the Cure similarly promote earlier and frequent screening.
By contrast, the US Preventive Services Task Force, an independent and non-partisan group of healthcare experts that looks at the risks and benefits of clinical screening and disease prevention programs, recommends that most women should delay getting regular mammograms until after they turn 50. The Task Force also recommends that screening be done every other year, not annually. Only women with a familial history of breast cancer should be screened earlier and more often.
Finally, groups like the American Cancer Society have staked out the middle ground. That organization, for example, recommends that women get annual mammograms from age 45 to 54, followed by screenings every other year once they turn 55.
This is all very confusing for most women, and it is about to be made even more so as a result of a Danish study published in this week in the Annals of Internal Medicine. That study, which looked at nearly 100,000 women diagnosed with breast cancer between 1980 and 2010, found that as many as one-third of those women might have been over-diagnosed and over-treated.
By comparing the medical records of those who participated in a mammographic screening program with those who did not, the Danish researchers discovered that there was no significant difference in the number of invasive tumors detected in the two groups. There was also no significant difference in the number of lives lost to cancer. Moreover, the number of non-malignant or slow-growing tumors detected was much higher in women who underwent regular mammography. Over 30 percent of the women in this group were diagnosed with a condition known as ductal carcinoma in situ, or DCIS.
Experts disagree on whether or not DCIS should be treated. It isn’t immediately life threatening, but some doctors still recommend treating it quickly and aggressively with chemotherapy, radiation or surgery in order to prevent it from becoming cancerous. Others, however, argue that DCIS carries such low risk of becoming invasive that it should be monitored only. The risks of treatment, these experts believe, outweigh the benefits. The Danish data, particularly the fact that the number of women with advanced tumors did not decrease despite an increase in the detection of ductal carcinoma in situ, would seem to support this theory.
As I have suggested previously, the information being given to women and to their doctors about if, when and how often to get mammograms is becoming increasingly confusing and conflicted. Rather than rely on one-size-fits-all guidelines from the American Cancer Society, American College of Radiology or the US Preventative Services Task Force, women should instead decide what is best for them based on their own personal circumstances, medical histories and prevention goals.
Someone with a familial history of cancer or someone who worries about their individual risk of cancer might choose to undergo more frequent screening, so long as they understand the potential harms of over-diagnosis. Others might instead choose to undergo less frequent screening, concluding the possibility that they might develop invasive cancer early doesn’t outweigh the risks of over-treatment.
I’ve said it before and I’ll say it again: screening saves lives, but not everyone needs to be screened early and often as some experts suggest.
[This blog entry was originally presented as an oral commentary on Northeast Public Radio on January 12, 2017, and is available on the WAMC website.]