Mammograms use ionizing radiation at a relatively high dose, which can contribute to the mutations that can lead to breast cancer.
You can get as much radiation from one mammogram as you would from 1,000 chest X-rays.
Mammography also compresses your breasts tightly, which can lead to a dangerous spread of cancerous cells, should they exist.
The main risk of mammograms is that they aren’t perfect. Normal breast tissue can hide a breast cancer so that it doesn’t show up on the mammogram. This is called a false negative.
And mammography can identify an abnormality that looks like a cancer, but turns out to be normal. This “false alarm” is called a false positive. Besides worrying about being diagnosed with breast cancer, a false positive means more tests and follow-up visits, which can be stressful.
To make up for these limitations, more than mammography is often needed. Women also need to practice breast self-examination, get regular breast examinations by an experienced health care professional, and, in some cases, also get another form of breast imaging, such as breast MRI or ultrasound.
As with other risk factors for breast cancer, evidence indicates that both age at exposure and the individual’s genetic profile influence the degree of increased risk for disease in women exposed to multiple mammograms. For example, women who had multiple mammograms more than five years prior to diagnosis had an increased risk for breast cancer, but the effect was only statistically significant for women whose first mammograms occurred before the age of 35 (Ma, 2008).