In her presentation at The North American Menopause Society (NAMS) 2021 annual meeting (September 22–25, 2021, in Washington, DC), Dr. Holly J. Pederson offered her expert perspectives on breast cancer prevention in at-risk women in “Chemoprevention for risk reduction: Women’s health clinicians have a role.” OBG Management talked with Dr. Pederson after the meeting to explore key points of the presentation.
Which patients would benefit from chemoprevention?
OBG Management: In your NAMS 2021 presentation on chemoprevention for cancer risk reduction, you make the point that for certain women, preventive medication can decrease the risk of breast cancer but is vastly underutilized. Which women specifically would benefit most from breast cancer risk-reducing medication?
Holly J. Pederson, MD: Obviously, women with significant family history are at risk. And approximately 10% of biopsies that are done for other reasons incidentally show atypical hyperplasia (AH) or lobular carcinoma in situ (LCIS)—which are not precancers or cancers but are markers for the development of the disease—and they markedly increase risk. Atypical hyperplasia confers a 30% risk for developing breast cancer over the next 25 years, and LCIS is associated with up to a 2% per year risk. In this setting, preventive medication has been shown to cut risk by 56% to 86%; this is a targeted population that is often overlooked.
Mathematical risk models can be used to assess risk by assessing women’s risk factors. The United States Preventive Services Task Force (USPSTF) has set forth a threshold at which they believe the benefits outweigh the risks of preventive medications. That threshold is 3% or greater over the next 5 years using the Gail breast cancer risk assessment tool.1 The American Society of Clinical Oncology (ASCO) uses the Tyrer-Cuzick breast cancer risk evaluation model with a threshold of 5% over the next 10 years.2 In general, those are the situations in which chemoprevention is a no-brainer.
Certain genetic mutations also predispose to estrogen-sensitive breast cancer. While preventive medications specifically have not been studied in large groups of gene carriers, chemoprevention makes sense because these medications prevent estrogen-sensitive breast cancers that those patients are prone to. Examples would be patients with ATM and CHEK2 gene mutations, which are very common, and patients with BRCA2 and even BRCA1 variants in the postmenopausal years. Those are the big targets.
Risk assessment models
OBG Management: Do you have a preferred breast cancer risk assessment model that you use in your practice?
Dr. Pederson: Yes, I almost exclusively use the Tyrer-Cuzick risk model, version 8, which incorporates breast density. This model is intimidating to some practitioners initially, but once you get used to it, you can complete it very quickly.
The Gail model is very limited. It assesses only first-degree relatives, so you don’t get the paternal information at all, and you don’t use age at diagnosis, family structure, genetic testing, results of breast density, or body mass index (BMI). There are many limitations of the Gail model, but most people use it because it is so easy and they are familiar with it.
Possibly the best model is the CanRisk tool, which incorporates the Breast and Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm (BOADICEA), but it takes too much time to use in clinic; it’s too complicated. The Tyrer-Cuzick model is easy to use once you get used to it.
OBG Management: When would results of the Tyrer-Cuzick assessment necessitate referral to a specialist?
Dr. Pederson: Risk doesn’t always need to be formally calculated, which can be time-consuming. It’s one of those situations where most practitioners know it when they see it. Benign atypical biopsies, a strong family history, or, obviously, the presence of a genetic mutation are huge red flags.
If a practitioner has a nearby high-risk center where they can refer patients, that can be so useful, even for a one-time consultation to guide management. For example, with the virtual world now, I do a lot of consultations for patients and outline a plan, and then the referring practitioner can carry out the plan with confidence and then send the patient back periodically. There are so many more options now that previously did not exist for the busy ObGyn or primary care provider to rely on.
Continue to: Chemoprevention uptake in at-risk women...