In a major cancer screening development, a study from the British Medical Journal found that an annual screening mammography didn’t result in a mortality benefit:
Women screened annually by mammography for 5 years had had a breast cancer mortality hazard of 1.05 compared with the control group during the screening period. During follow-up for a mean of 22 years, the mammography group had a breast cancer mortality hazard of 0.99 versus the control group. Neither value was statistically significant.
Worse, mammograms overdiagnosed cancers, leading to unnecessary mastectomies, radiation therapy and chemotherapy: “After 15 years of follow-up, the mammography group had an excess of 106 breast cancers attributable to overdiagnosis.”
Undoubtedly, the media will be all over this one. It’s already the most emailed article in the New York Times. What does this mean for patients?
Mammograms are slowing approaching PSA territory, where PSAs also show no mortality benefit, and cannot predict which cancers are dangerous or not. Physicians soon will encounter similar issues when discussing mammograms with women as they do with discussing PSAs with men.
The USPSTF currently suggests annual mammograms starting at age 50 and a discussion of mammograms starting at age 40. Will these recommendations change? Probably not immediately. Guidelines normally take a few years before adjusting to disruptive study findings.
But as we’ve seen with other screening tests, it’s difficult to reduce cancer screening once the proverbial cat’s out of the bag. Consider this comment from the Times article, which is representative of a significant proportion of women:
I’m a creature of the baby boom generation, trained to have my baseline in my early 40s, and annually after that. Because I have certain health issues based on early menopause–as well as a strong family history of cancer — I will continue to follow the “old” guidelines (being debated and revised as I type).
Another factor left out of this study, and indeed the whole discussion which is emotional, political, and deeply personal, is the plight of women with dense breasts who find it hard to do monthly self-exams. There is a certain security in knowing each year that there have been no changes on my films from year to year.
No nothing is certain in life. But my comfort level is exactly that: my comfort level. So until they tell me screenings are 100% harmful, I will continue to have them.
You will undoubtedly hear many stories of patients who would rather be 100% informed and risk overdiagnosis than live with the unknown. Peace of mind cannot be quantified, yet still has value for many patients.
My approach? Same as always with cancer screening issues shaded in grey. Make mammograms an individual patient decision. Inform patients of the USPSTF recommendations and the results of the BMJ study, then get a sense of their values and how important it is that they know their breast cancer status.
Then make a shared decision whether to order a mammogram or not, which may be different for each individual patient.
