How often should I get a mammogram?

by Michelle McElroy, DO

Let’s first talk about the pros and cons of mammograms so you can make an informed decision. A mammogram is an X-ray of your breast that is a screening test for breast cancer. The toxic effects of mammogram radiation are finally being acknowledged as a factor in the development of breast cancer. A recent study published in BMJ and another in The New England Journal of Medicine showed that mammograms don’t save lives.

The vast majority of mammograms today are 2-D or digital. Some problems with mammograms are:

False-positive results. False positive results occur when a radiologist sees an abnormality on mammogram but no cancer is found. This leads to further testing with diagnostic mammograms, ultrasounds and/or biopsy. False positives lead to anxiety; increase costs due to additional testing and can cause physical discomfort. The chance of false positives increases with the number of mammograms performed. Fifty percent of women having yearly mammograms for 10 years will have a false positive.

Over diagnosis and overtreatment. Mammograms can detect DCIS (ductal carcinoma in-situ, a non-invasive precancerous lesion) and small cancers that would never cause symptoms or threaten a women’s life. This phenomenon is called “over diagnosis”. The unneeded treatment that follows is “overtreatment”. Because doctors cannot distinguish the cancers and DCIS that need to be treated, they are all treated.

False-negative results. False negatives occur when a mammogram is read as negative and cancer is actually present. This rate is approximately 20%.

There is a newer form of mammography, 3-D or tomosynthesis, that has less radiation exposure and shows promise to have a lower false-positive rate. A study, TMIST, comparing 2-D to 3-D started enrolling patients October 2017. It is designed to be a 5 year study. We will have to wait for the results to know for sure if it is a better option.

The current recommendations for mammogram by the American Cancer Society (ACS) are every year from the age of 45-54. It is every other year after that as long as you are healthy. Knowing the risks, you should have a discussion with your provider about what is best for you.

If you don’t have insurance and need or want a mammogram call 1-800-232-4636 or 1-800-422-6237 to find out about local programs that offer free or low cost mammograms.