Recommendations for breast cancer screening have varied over time and continue to vary. Organizations have different recommendations for when women should start being screened for breast cancer and how often they should be screened. Breast cancer is most commonly screened for with a mammogram, or an X-ray of the breasts.
Some organizations have recommended annual screening mammograms starting at age 40. The U.S. Preventive Services Task Force (USPSTF) recommends that average risk women get a mammogram every other year from 50-74 years of age. The USPSTF recommends women ages 40-49 discuss breast cancer screening with their health care provider (1). Family history of breast cancer is a factor that could weigh into starting mammograms before age 50.
At present, these recommendations are the same for women with and without Down syndrome. However, breast cancer is less common in women with Down syndrome. A number of studies have shown this including one we published in 2015. The abstract can be reviewed at this link. What does that mean for breast cancer screening for women with Down syndrome? Due to a lower incidence of breast cancer, should mammogram screening be different in women with Down syndrome?
To help answer that question, we had the opportunity to work with an amazing team that used a type of computer modeling (called collaborative simulation modeling) to assess screening mammograms for women with Down syndrome. A paper was published this week about the study. The abstract can be read at this link.
What do the models show for women without Down syndrome?
The simulation models used in the paper can be used to estimate how many mammograms would need to be done to prevent one death from breast cancer following a particular screening recommendation. They have been used previously to study women without Down syndrome. For women without Down syndrome, if the recommendation is to get mammograms every other year between ages 50 and 74, it would take 2,240 mammograms to prevent one death from breast cancer. If the recommendation is to get mammograms every year between ages 40 and 49 and then every other year from ages 50 to 74, it would take 7,800 mammograms to prevent one death from breast cancer in women without Down syndrome.
What did the models show for women with Down syndrome?
For women with Down syndrome, the models show far higher numbers of mammograms. For women with Down syndrome, if the recommendation is to get mammograms every other year between ages 50 and 74, it would take 16,735 mammograms to avert one breast cancer death. Additionally, it is estimated that 209 women with Down syndrome would have a benign (negative for cancer) biopsy for every breast cancer death prevented. If a mammogram was done only once at age 50, it would take about 14,000 mammograms to prevent one death from breast cancer. The number of mammograms increases if started at a younger age. If every woman with Down syndrome in the United States between the ages of 50 and 74 had a mammogram every other year, 0.4 breast cancer deaths would be prevented.
Breast biopsies are usually done under anesthesia. Women with Down syndrome have an increased risk of complications from anesthesia compared to women without Down syndrome. While it was not part of this study to evaluate how many women might be harmed by anesthesia/surgery, it poses an additional risk for women with Down syndrome. According to the estimates from the model, 209 women would have a benign biopsy (and the risk of anesthesia) for every life from breast cancer saved.
What about women with Down syndrome who have a family history of breast cancer? Unfortunately, we do not have separate data for women with Down syndrome who have a family history of breast cancer.
What did the study conclude?
The study concluded that, for women with Down syndrome, compared to average risk women without Down syndrome, there is a significantly higher harm/benefit ratio. In other words, there is a greater risk of harm (unnecessary mammograms, complications, etc.) to achieve the desired outcome (prevention of deaths from breast cancer).
We recommend you review and discuss health screening recommendations with your health care provider to make a decision that is appropriate for your circumstances. Consider the available studies, the lack of information regarding family history of breast cancer for women with Down syndrome, and your own personal preferences for health screening.