Fact or Myth: Do Yearly Mammograms Save Lives?

This is a MYTH.

do mammograms cause cancerScience has turned its attention to the practice of getting yearly mammograms, and recent research is giving annual mammograms a pretty solid thumbs down. Studies are showing that not only do yearly mammograms not save lives, but they can also hurt more women than they help due to over-diagnosis, over-treatment, and even radiation-induced cancer. Let’s take a look at what science says:

2010, New England Journal of Medicineyearly mammograms saved 2.4 out of 100,000 lives, a reduction so small as to be deemed statistically irrelevant.

2011, The Lancet Oncology — women who got yearly mammograms had a higher collective incidence of invasive breast cancer over 6 years than women who received far fewer mammograms.

2014, BMJresearchers followed 90,000 women for 25 years. The rates of breast cancer deaths in women who got yearly mammograms versus those who didn’t were statistically identical. This study also showed that mammogram screening had adverse effects. The New York Times reported: “One in five cancers found with mammography and treated was not a threat to the woman’s health and did not need treatment such as chemotherapy, surgery, or radiation.” And the authors of the study concluded:

“Annual mammography in women aged 40-59 does not reduce mortality from breast cancer beyond that of physical examination or usual care when adjuvant therapy for breast cancer is freely available. Overall, 22 percent of screen detected invasive breast cancers were over-diagnosed, representing one over-diagnosed breast cancer for every 424 women who received mammography screening in the trial.”

2015, JAMA Internal Medicinethe latest research from Harvard and Dartmouth likewise shows no connection between yearly mammograms and a higher likelihood of breast cancer mortality. Researchers examined cancer registry data from 16 million women in 547 counties in the United States. Results showed that mammograms detected small, usually harmless, non-lethal tumors. These are tumors that are completely benign, and while they can be “cured” and killed, there is no need for treatment. The danger lies in widespread over-diagnosis of breast cancer, and subsequent unnecessary treatment.

Yearly mammograms are associated with a higher incidence of breast cancer. For every 10-percentage point increase in screening rates, breast cancer diagnoses go up by 16%. Most of these diagnoses are for early-stage breast cancer, and even when 1.8 times as many breast cancers are identified, breast cancer mortality stays the same.

Researchers recommend yearly mammograms for women at high risk of developing breast cancer, and also suggest that for some women waiting and watching may be a better first step than taking immediate and invasive action.

How Effective Are Mammograms?

According to the National Cancer Institute (NCI) mammograms fail to detect up to 20% of breast cancers. Women with dense breasts are at an increased risk for false negatives. In fact, 75% of women with dense breasts are at risk of breast cancer not being detected by mammograms alone. This highlights the importance of an annual physical breast exam, which can go a long way in detecting breast cancer.