How often should you have a mammogram?
Many women are confused about how often they should have mammograms, because recommendations from various health organizations differ. The most important of these discrepancies concerns whether women who are between the ages of 40 to 50 and at average risk of breast cancer should have mammogram screenings at all.
Breast cancer is the most frequently diagnosed cancer among women in the United States, not including skin cancer, and is second only to lung cancer as a cause of cancer deaths. One out of every eight women will be diagnosed with breast cancer sometime in her life. The risk for breast cancer increases with age. The 10-year risk for breast cancer is 1 in 69 for a woman at age 40, 1 in 42 at age 50, and 1 in 29 at age 60. The good news is that breast cancer deaths have been decreasing since 1990, by 2.3 percent annually overall and by 3.3 percent for women aged 40 to 50. This decrease is largely attributed to the combination of mammography screening and improved treatment.
Before 2009, health organizations generally advocated routine mammograms every year or two starting at age 40, and annually starting at age 50. However, in 2009, the United States Preventive Services Task Force issued new recommendations that changed the age of the initial mammogram to 50 years, with mammograms every two years beyond that age. Strong objection to this change was immediately made by the American College of Obstetricians and Gynecologists (ACOG), among others.
The task force concluded that the potential harm of routine mammograms outweighs the benefits for women aged 40 to 50. Women in this age group have more dense breasts than older women, which leads to more “false positive” screening results. About 10 percent of mammograms in this age group show a possible abnormality, which leads to a more detailed mammogram and possibly an ultrasound exam. One in eight of these women will go on to have a biopsy, and one third of the biopsies will be positive for cancer. The task force asserts that the number of women who do not have cancer but undergo the anxiety and pain caused by these follow-up procedures is not worth the likelihood of a cancer diagnosis. Increased radiation exposure is another reason cited by the task force.
The American College of Obstetricians and Gynecologists disagrees. ACOG asserts that an estimated 7,000 lives can be saved by screenings in this age group, a savings that outweighs the temporary anxiety and minor pain of further testing. The additional radiation exposure is not significant enough to cause harm.
The task force also recommends discontinuing routine mammograms at age 74, while ACOG does not advocate halting mammograms at any age.
Mammography is a very effective tool in diagnosing breast cancer and has saved countless lives. Women should discuss their individual risk and concerns with their physician when deciding the frequency of mammograms.