Abstract P5-04-01: Screening Patterns of Mammography and Breast Magnetic Resonance Imaging Following Cancer Genetic Testing in an Integrated Health Care System
Authors: Guo Boya , Knerr Sarah , Wernli Karen , Mittendorf Kathleen , Feigelson Heather , Gilmore Marian , Jarvik Gail , Kauffman Tia , Keast Erin , Liles Beth , Lynch Frances , Muessig Kristin , Sasaki Sonia , Veenstra David , Zepp Jamilyn , Wilfond Ben , Goddard Katrina , Devine Beth 
Published: March 2023

Abstract
Background Patients at high-risk for breast cancer with genetic mutations are recommended to receive annual breast MRI in adjunct to annual mammography. Despite 15 years of clinical guidelines, uptake of annual breast MRI remains low. Further, little is known about screening patterns across genetic test results in patients tested for hereditary cancer susceptibility as part of usual care.
Methods We conducted a retrospective cohort study in an integrated health system among women aged ≥18 years old, without prior breast cancer who had genetic testing for high penetrance hereditary cancer susceptibility genes between January 1, 2010 and December 31, 2018. Genetic test orders and results (pathogenic or likely pathogenic (P/LP) variant(s), negative, or variant of uncertain significance (VUS)) were obtained from health system administrative and laboratory data. Mammogram and breast MRI use data were extracted from electronic health records and claims data. To characterize screening patterns, we calculated average proportion of time covered (PTC) as the number of days covered by mammography and/or breast MRI divided by the number of days from screening eligibility until the earliest censoring event: end of observation period, reached age 75 years, breast cancer diagnosis, death, bilateral mastectomy, or disenrollment in the health system. Per National Comprehensive Cancer Network (NCCN) guidelines, women with P/LP variants in BRCA1/2, TP53, PALB2, CHEK2, ATM, and NF1 became eligible for screening on either the day they received their genetic test result or reached age eligibility and received one year of covered time for each mammogram or MRI imaging procedure received. Per Healthcare Effectiveness Data and Information Set (HEDIS) performance measures, all other women became eligible for screening at age 50 years and received two years of covered time for each mammogram received. Average PTC was calculated overall, by genetic test results, and by screening type. Poisson regression was used to determine the association between average PTC and patient-level factors (age at test, race/ethnicity, and genetic mutations) and guideline factors (recommended screening age state).
Results Of 1,167 women meeting the inclusion criteria, 140 (12%) had P/LP in high penetrance breast cancer susceptibility genes (Table 1). Average PTC for individuals with a high penetrance susceptibility gene was 34.4% for MRI, 47.6% for mammogram, 63.2% for either MRI or mammogram, and 19.0% for both screening tests. The average PTC for those who tested negative, had VUS only, and had P/LP variants in genes unrelated to breast cancer was 50.3%, 44.4%, and 40.6%, respectively. Poisson regression model showed that among those with P/LP variants in high penetrance breast cancer genes, average PTC for annual MRI was positively associated with recommended screening initiation age ≥40 years (incident rate ratio [IRR]=2.07, 95% confidence interval [CI]: 1.94-2.20), higher absolute lifetime risk of breast cancer (IRR=1.38, 95% CI: 1.31-1.49), being 40-59 years old at genetic testing (IRR=1.04, 95% CI: 1.01-1.06), and non-Hispanic White race/ethnicity (IRR=1.10, 95% CI: 1.06-1.14).
Conclusions Use of breast screening in women who had a P/LP variant(s) in high penetrance breast cancer susceptibility genes was low and not consistent with clinical guidelines, but comparable to the use of screening in women with negative and VUS results. Our findings suggest the need to improve screening in high-risk women with known genetic mutations and women at average risk.
Table 1. Average PTC by NCCN and HEDIS recommendation.
Citation Format: Boya Guo, Sarah Knerr, Karen Wernli, Kathleen Mittendorf, Heather Feigelson, Marian Gilmore, Gail Jarvik, Tia Kauffman, Erin Keast, Beth Liles, Frances Lynch, Kristin Muessig, Sonia Sasaki, David Veenstra, Jamilyn Zepp, Ben Wilfond, Katrina Goddard, Beth Devine. Screening Patterns of Mammography and Breast Magnetic Resonance Imaging Following Cancer Genetic Testing in an Integrated Health Care System [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P5-04-01.