A standard mammogram, left, and molecular breast imaging (MBI) of a 45-year-old woman's breast reveal cancer. /AP/Mayo Clinic
Here’s a tough question for women over 40:
Could a mammogram save your life? Or could it lead you into a costly false cancer scare?
Could it lead you undergo surgery, radiation or chemotherapy that you don’t actually need?
A provocative new bit of data analysis suggests the overall benefit to women of getting annual mammograms may be small, while the risk of a false alarm is enormous. The data reignites the debate over whether all women really benefit from annual mammograms.
The study was published in JAMA’s Internal Medicine journal Dec. 30.
Dr. H. Gilbert Welch and Honor Passow of Dartmouth’s Institute for Health Policy and Clinical Practice in Hanover, New Hampshire looked at existing research on mammography and applied their own statistical analysis.
Here’s what they found:
Q: How many women are likely to experience a false cancer scare at some point?
A: Nearly half.
Among 1,000 50-year-old women given a mammogram every year for 10 years, the authors estimated that 490 to 670 of them would be told they may have cancer and be sent for further tests, including biopsies. (The range reflects the varying performance of the radiologists – some have higher false positive rates than others.)
Chemotherapy is administered to a cancer patient via intravenous drip. /AP
Q: How many of those 1,000 women over 50 who got mammograms every year over a decade wound up undergoing unnecessary cancer treatments – surgery, radiation or even chemotherapy?
A: Between 3 and 14 would be treated unnecessarily for cancer.
It’s all worth it if lives are saved, right? Breast cancer is the second leading cause of cancer deaths among U.S. women.
After looking at the data, however, the authors weren’t convinced that annual mammograms save many lives.
Q: How many of those 1,0000 women over 50 who got mammograms every year over a decade avoided death from breast cancer?
A: Taking an optimistic view of the data, the authors estimated that between .3 and 3.2 breast cancer deaths were avoided.
But how can this be explained? Haven’t women been told for decades that annual mammograms save lives?
According to Welch, who also published a commentary in the New York Times, the way we prevent, diagnose and treat cancer has changed – for the better.
More effective chemotherapy drugs are enabling doctors to stop cancer at various stages of progression. This means, statistically, that early detection becomes less critical to survival than it used to be.
Also, thanks to genetics, we now know that not all women carry the same risk of getting breast cancer. A thorough patient history and, if warranted, a genetic test, may be more meaningful screening tools for doctors and patients.
About 1 in 500 women carry the dangerous version of BRCA 1 or BRCA 2 genes, giving them a lifetime risk of breast cancer of 60 percent or more. BRCA mutations are a risk for men, too. The risk of male breast cancer is about 1 percent in the general population. But for men who carry the BRCA 2 mutation, the risk of breast cancer rises to 6 to 8 percent.
But BRCA mutations only account for between 5 and 10 percent of all breast cancers.
What about everyone else?
The U.S. Preventive Services Task Force is charged with evaluating medical evidence and issuing recommendations. In 2009, the task force changed its recommendations on mammograms to significantly reduce how often women go for the test.
The task force suggested that women under age 50 simply do not need routine mammograms. Women aged 50 to 74 should get a mammogram every other year. It said there was insufficient evidence to conclude whether women over 75 should get mammograms.
When the recommendations were issued, they caused an uproar. That’s because the task force’s decisions typically dictate what insurance and Medicare will cover. And, they came amid the debate over health reform, as the specter of “death panels” were being used to stoke fear of health reform.
As a result, the Affordable Care Act now specifically requires insurance companies to follow the task force’s old 2002 guidance, which recommended mammograms every 1 to 2 years after age 40.
Dayna Smith hugs survivor Sharon Vomero during the American Cancer Society's Making Strides Against Breast Cancer Walk in October. / Richard Graulich/PBPost
So is there really a harm in too many mammograms? Beyond unnecessary cancer treatments or anxiety-provoking overdiagnosis, or radiation exposure, there is a financial consideration.
Medicare spends about $1 billion a year for mammography screening – that’s about same amount it spends on actual breast cancer treatment. And insurance premiums reflect the cost of mammograms and overtreatment.
But what is the value of one life saved? That’s one question the data doesn’t answer.
