If you are a woman who has recently had a mammogram, you may have received a letter from your radiologist (actually signed by me) recommending that your next mammogram be in one year. You may also have seen in your MyHealth account (the UVM Medical Center patient portal) that you are not due for screening for two years. Why this discrepancy?
As a radiologist specializing in breast imaging at the University of Vermont Medical Center, I frequently get asked this question. There has been an ongoing controversy about when women should begin screening mammography and how often they should be screened. There are many different points of view on this topic.
Here are the points on which there is clear evidence:
Screening mammography saves lives by finding cancers when they are smaller and at an earlier stage. This statement has been recently verified by a study* modeling lives saved with three different popular screening regimens. It found that beginning screening at 40 and screening every year reduced the death rate from breast cancer by almost 40 percent, whereas beginning at 45 (screening annually from 45-55 and then every other year after 55) reduced it by just over 30 percent and screening beginning at 50 and screening every other year reduced the death rate by just over 23 percent.
Finding cancers earlier allows less debilitating and less costly treatment options.
Mammography is not a perfect test and frequently (about 7-10 percent of the time) identifies abnormalities that are not cancer (also known as false positives). This leads to additional testing which can certainly cause anxiety and cost. Screening less frequently will decrease the total number of false positives a woman will potentially experience during her lifetime, as she will have fewer total screening episodes.
Because the incidence of cancer is lower in younger women, of those called back, more of them are false positives than for those called back who are older. But 16 percent of cancers are diagnosed in women in their 40s and 40 percent of lives lost from cancer come from women diagnosed in their 40s. You should be aware that 75 percent of patients diagnosed with breast cancer have no family history. Screening only those with family history would deny 75 percent of women the opportunity for early diagnosis.
Screening also misses some cancers, particularly in those with dense breasts. Each woman has a different breast density. You cannot know your breast density by a physical exam, it is only determined on a mammogram. Dense breasts are normal (not a disease) and are found in 40-50 percent of women. Click here to access information and resources about breast density.
Some cancers are more dangerous than others and some may even stay dormant for a period of time and may not cause harm. This is known as overdiagnosis. We don’t know at this point which ones those might be; so currently all patients diagnosed with cancer are generally treated. In the future, we hope to have more knowledge about which cancers might be watched instead of being aggressively treated. Screening less frequently will not improve overdiagnosis.
Here are the points of contention:
Some medical societies have recommended less frequent screening for women without family histories and have recommended beginning later (45 or 50). These recommendations are based on the desire to balance the potential benefits (lives saved and easier and less costly treatment) with risks or harms (more frequent false positives, including additional testing, biopsies, cost and anxiety). This “balance” is based on assigning value to the benefits versus the harms. In my opinion, deciding on the value of a life saved compared with the inconvenience and harm of additional testing should not be the role of a medical society.
Instead, each woman should be informed of the potential benefits and harms and should have the opportunity to use her own value system to make this decision. One woman may be willing to experience callbacks and even biopsies in order to insure that if ultimately diagnosed with cancer, that it is caught early, thus giving her the best fighting chance and potentially allowing less invasive and costly treatment options. She would choose to be screened every year beginning at 40 and might opt for additional screening if her breasts are dense.
Another may be put off by the possibility of additional testing and may decide on a more conservative screening schedule; beginning at 50 and screening only every 2 years. Neither path is incorrect. Each is the right path for that woman. Our job as medical professionals is to inform you of what you might have to do for the opportunity to benefit from early diagnosis and your job is to decide what you are willing to undergo for that opportunity.
MyHealth Online recommends a screening regimen (beginning at 50 and screening every 2 years) that everyone should be willing to do. We radiologists recommend beginning at 40 and screening every year. This recommendation is given to inform you of the path with the greatest potential for lives saved; not as a hard rule. It is ultimately your choice. We suggest you have a discussion with your provider about risks and benefits of screening, to include your personal risk factors and breast density before making a decision.
We know the recommendations are confusing. We are here to help. Contact us with your screening questions at firstname.lastname@example.org.
Sally Herschorn, MD, is Division Chief and Medical Director of Breast Imaging at the University of Vermont Medical Center and associate professor of Radiology at the Larner College of Medicine at the University of Vermont. She is also Vice Chair for Patient and Provider Experience in Radiology.
*Ref: (Arleo EK, Hendrick RE, Helvie MA, Sickles EA. Comparison of recommendations for screening mammography using CISNET models. Cancer DOI: 10.1002/cncr.30842.)