Six Questions to Ask About Mammograms

Regular mammograms are the best way to detect breast cancer at the earliest possible stage. Mammograms identify cancer before symptoms (such as feeling a lump) occur. Early cancers found on a mammogram are often small, confined to the breast (meaning they haven’t spread to other areas), and can be the easiest to treat.

Recently, questions arose about whether the benefits of mammography outweigh some possible risks. Mammograms can identify abnormalities that turn out not to be cancer. This can result in additional testing, visits, and sometimes procedures, which can cause stress and anxiety. Mammography also exposes women to a small amount of radiation, although the amount is so small that the actual risk can’t be measured.

In response, a U.S. task force convened to evaluate research related to breast cancer screening. They announced, and some professional organizations agreed, that women don’t need to start regular mammograms until age 45 or even 50. And, rather than have screenings every year, the new guidelines recommended mammograms every other year for some women, depending on their age and breast cancer risk.

The latest guidelines caused an uproar among women and doctors who believe screening mammograms save lives. Duke radiologist Jay Baker, MD, strongly agrees that screening is beneficial. He said the new guidelines underestimate the value of early detection and overestimate the risk of potential harm. 

If you are at average risk for breast cancer, Dr. Baker said screening should start at age 40. “Everyone agrees, even those who aren’t the biggest fans of mammography, that the most lives and the most years of life are saved by starting screening at age 40. The data are very clear.” he said.

According to the Society for Breast Imaging, breast cancer risk starts increasing around age 40, and one in six breast cancers occurs in women between the ages of 40 and 49. A 2014 study found that most women in their 40s who developed breast cancer were not considered at high risk. Three out of four women who develop breast cancer have no family history of the disease. Other studies confirm that about half of fatal breast cancers are diagnosed before the age of 50, and about 30% of the total years of life lost to breast cancer are from women who were diagnosed in their 40s.

Bottom line: Start regular mammograms at age 40. If you are at high risk for breast cancer (that is, you carry one of the breast cancer genes, or you have a strong family history of the disease), you may benefit from starting screening before age 40. Speak with your regular doctor about your risk and a plan for screening.  Regardless of your risk factors, if you feel a lump in your breast, schedule a mammogram immediately, no matter your age.

Screening every year saves lives and results in a 25 to 40% decrease in lives lost, said Dr. Baker. The Society for Breast Imaging reports that the longest running breast screening trials in history show that regular mammography screening – meaning once a year -- cuts breast cancer deaths by almost a third in all women age 40 and over.

Annual mammograms are also important if you have been told you are at high risk for breast cancer – because of a family history, because you have been told you have dense breasts, or because you have a genetic mutation such as BRCA 1 or 2.

Bottom line: Annual mammograms increase the likelihood of catching breast cancer at the earliest stage and reduce the risk of dying prematurely of breast cancer.

While some data suggest women over age 74 no longer need mammograms, Dr. Baker said most of the research has simply not included women 75 years and older. Rather, he said research shows there are benefits to annual screening mammograms as long as you are in good health, and have about eight to ten years of life expectancy.

Bottom line: Continue annual mammograms as long as you are healthy and have several good years of life ahead.

Three-dimensional mammography, also known as breast tomosynthesis, is a form of digital mammography. Unlike standard digital mammograms, which create a two-dimensional view from the top and sides of your breast tissue, 3D tomosynthesis mammograms take low-dose images from many angles at essentially the same overall radiation dose as regular 2D mammograms. A computer then reconstructs those images into a 3D image of your breast.

Research indicates 3D mammograms find 25 to 35% more breast cancers and result in up to 30% fewer false positive results. Data also show 3D mammography does a better job finding breast cancer in dense breast tissue.

All Duke sites in Durham, Orange, and Wake counties use 3D tomosynthesis for all screening and diagnostic mammograms.

Bottom line: Talk to your doctor about whether you will benefit from a 3D mammogram. 

Duke offers mammography in several convenient locations. Saturday appointments are also available. When choosing where to have your mammogram, consider whether the doctors reading your screens are dedicated breast imaging radiologists. Data show breast imaging radiologists find more breast cancer and have fewer false positives.