I failed to release this column during breast cancer awareness month in October. Women are always interested to learn about what they can do to reduce their risk of developing this dread disease. Breast self examination (BSE) is one thing women have traditionally performed, but some readers may have read that this monthly ritual is no longer recommended. The practice is associated with an increased risk for false-positive results (feeling a lump that is not cancerous) that can lead to additional testing and invasive procedures like breast biopsies and surgeries (not to mention the associated worry).
Finding a lump is more likely for young women who have naturally fibrous or “lumpy” breasts. Conversely, women who do not feel a lump may gain a false sense of security and not obtain recommended screening mammography.
For the rest of the article, I’d like to focus on mammography and recommendations for using it as a screening tool. Certainly mammography is not without controversy. Disagreement exists, even among professional medical societies, regarding the age to start screening mammography, how often to do it, and when to discontinue them. Though the science is getting more solid, older dogma about screening mammography persists.
It is important to note that mammography does not detect or rule out cancer 100 percent of the time. As a general rule, detection of cancer is lower in women younger than 50, those who have denser breast tissue, or who are receiving hormone therapy. Dense breast tissue makes it more difficult to identify cancers and also leads to more false positive readings (seeing something that does not turn out to be cancer).
Anywhere from six to 46 percent of women who have a cancer and dense breasts will be missed on mammography. Most imaging centers now perform tomosynthesis, a special digital mammogram that improves the ability to identify tumors in dense breast tissue. There are other studies such as breast MRI that can find tumors more easily in dense breasts, but it is not approved as a routine screening test and is very expensive.
As a woman ages, her breasts become less dense making it easier to see abnormalities on a mammogram. The risk of breast cancer also increases with age. Therefore, the chances that an abnormal mammogram is due to cancer also increases with age. This accounts for some of the controversy in recommending mammograms for younger women who naturally have more false positives and are subjected to more biopsies, anxiety, expense, etc. On average, about one in ten women receive a call to return for additional testing following their screening mammogram. Of these, about five in 100 will end up being diagnosed with cancer. About half the women screened annually over ten years will have a false positive mammogram resulting in additional testing, biopsies, etc.
Concerns have surfaced in recent years that routine screening mammography leads to “overdiagnosis,” meaning detection of cancers that are not likely to lead to premature death. This in turn leads to women undergoing treatments that can cause real harms (surgery, radiation, chemotherapy, as well as the quality of life issues that go with them), without an increase in lifespans. Various studies have shown 20 to 54 percent of breast cancers are overdiagnosed. All breast cancers are not alike; some even regress on their own. The challenge is trying to determine if a woman’s cancer is something to watch or to treat.
So, when and how often is screening recommended? Again, due to the controversial nature of screening, both in the medical community and lay press, you will read differing opinions. It’s important to keep in mind when considering breast cancer screening that women understand it’s not all to their benefit and that there are real potential harms involved. These should be discussed with their health care provider before testing is ordered. Rather than try to summarize the various recommendations, you can read more about them at the following sites:
US Preventative Services Task Force: bit.ly/3oujBZn
American College of Obstetricians & Gynecologists: bit.ly/2XnYxYj
American Cancer Society: goo.gl/W9e3B
American College of Radiology: bit.ly/35pwmN0