Personalized Breast Screening
Researchers are not only trying to identify new screening technologies, they are also trying to develop new protocols that maximize the benefit of these technologies. Personalized screening, also sometimes referred to as risk-based screening, is a new technique that that is currently being discussed and explored. This approach would use a woman’s individual breast cancer risk factors to determine the age she should start screening, how often she should be screened, and what type of breast cancer she is at risk of developing.
One of the leaders in this field of research is breast surgeon Dr. Laura Esserman, the director of the Carol Franc Buck Breast Care Center at the University of California, San Francisco.
BCT spoke with Dr. Esserman about personalized screening and a clinical trial she is planning to evaluate its effectiveness.
Q: What is personalized screening?
A: Personalized screening is a process to determine how frequently you should be screened based on your actual risk of getting which type of breast cancer. We know that breast cancer is not one disease and we don’t treat all breast cancers the same way. We determine treatments by, for example, whether the tumor has estrogen receptors or if it is aggressive. Yet, we continue to screen everyone in the same way.
Q: How would you study personalized screening?
A: We are trying to set up a trial where we would compare standard annual screening for women between the ages of 40 and 80 to a personalized screening program that would assign a woman to a screening frequency based on her actual risk of developing breast cancer and which type of cancer she is at risk of developing.
Q: What risk factors would you take into account?
A: We already know about a number of risk factors, like the BRCA mutations or breast density. For example, women who have very dense breast tissue are at higher risk than those who have less dense breast tissue, and there is some evidence to suggest those cancers might be faster growing as well. Annual screening or a different imaging technique might make sense for these women. Scientists are also developing ways to predict who is more at risk of developing a hormone negative tumor and who is more at risk of developing a hormone-positive tumor. We would use this information to help determine how often a woman should be screened.
Q: What is the goal of the study you are planning?
A: We hope to show that personalized screening is as safe or better than annual screening in finding the same number of early tumors. We also hope to show that personalized screening does not delay finding more advanced tumors.
This study will also allow us to profile every cancer that we find, which will help us learn more about who is at risk and for what kind of cancer, which will further improve our ability to assess risk. We hope to be able to say, for example, “You are at risk for a HER2-positive cancer or you are at risk for an ER-positive cancer.” Then, we would have a strategy for screening based on the cancer type, which would allow us to think about prevention in a totally different way.
Q: Why is a study like this important?
A: The only way to sort out what we should be doing is through a screening trial. We are in a situation where some women are being screened every year while other women are being screened every other year. The United States Preventive Services Task Force (USPSTF) has already said screening should be every other year, starting at age 50, for women who are at average risk. The USPSTF guidelines are less clear for women between the ages of 40 and 50, leaving the decision up to the patient and her provider, but not providing any guidance on what factors should go into this decision.
I don’t think there is any data that suggests we should be screening all women every year. What we need to do is pick a targeted group who should be screened every year, and then the rest we should screen every other year, following the guidelines recommended by the USPSTF.
Q: What about using alternatives to mammography?
A: Until we identify something that is better, we should be sticking with mammography for breast cancer screening. We can test new tools in women with extremely dense breast tissue or in others who are high risk. But you have to test these tools to see if they are or are not better than mammography, and a new test shouldn’t be the standard unless we can demonstrate that it is better. For example, studies have shown us that using ultrasound is not better at detecting breast cancer and that it increases a woman’s chance of having a biopsy. In terms of breast density, we need to determine how to measure density in a standard way and how to interpret it in a way that can be similar across studies.
It makes sense that women have a lot of questions about screening. Now, we need to get going and answer them.
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