Abstract P6-02-07: Uptake of Breast Cancer MRI Screening in Patients After Multiplex Gene Panel Testing

Abstract Purpose: Multiplex gene panel testing (MGPT) is used to identify individuals with an inherited susceptibility to cancer. However, little is known about the uptake of screening and surveillance among patients after MGPT and genetic counseling. The purpose of this study was to measure the uptake of guideline-concordant breast cancer screening after genetic testing and counseling. Patients and Methods: 2,000 patients who met NCCN testing guidelines or had ≥2.5% probability of a pathogenic/likely pathogenic variant (PV) were recruited at three cancer genetics clinics (University of Southern California (USC) Norris Comprehensive Cancer Center, Los Angeles County + USC Medical Center, Stanford Cancer Institute) from July 2014 through November 2016. All patients had 25- or 28-gene MGPT and results were disclosed by a genetic counselor, who provided screening recommendations to patients based on their risk. Post-test surveys were administered at three months, six months, one year, two years, and three years. Results: 1,614/2,000 (80.7%) patients were female and 1,147/1,614 (71.7%) completed at least one survey regarding MRI screening for breast cancer over the three years of longitudinal follow-up. Of these, 94/1,147 (8.2%) patients tested positive for at least one PV in a breast cancer risk gene; 58/94 (61.7%) tested positive for PVs in a high-risk breast cancer gene (BRCA1/2 (n=53), CDH1, PALB2, TP53 (n=5)), and 34/94 (36.2%) of patients tested positive for a PV in a gene characterized as moderate-risk at the time of disclosure (CHEK2, ATM, NBN). MRIs were recommended to 43/58 (74.1%) patients with a high-risk breast cancer gene PV, 20/34 (58.8%) patients with a moderate-risk gene PV, and 171/1,053 (16.2%) patients without a breast cancer risk gene PV. Multivariate logistic regression models revealed that patients with a high-risk gene PV were more likely to undergo MRI screening within 3 months of receiving genetic test results (OR=6.54 95% CI [3.09 - 14.43], p< 0.001), within one year (OR=1.34 95% CI [1.18 - 1.52], p< 0.001), two years (OR=1.43 95% CI [1.24 – 1.65], p< 0.001), and three years (OR=1.44 95% CI [1.25 – 1.66], p< 0.001) when compared to patients without a PV. Patients with a moderate-risk PV were also more likely to have undergone MRI within 3 months of receiving genetic test results (OR=2.89 95% CI [1.05 - 7.81], p=0.036), within one year (OR=1.33 95% CI [1.10 - 1.62], p=0.004), two years (OR=1.31 95% CI [1.09 - 1.59], p=0.004), and three years (OR=1.44 95% CI [1.18 - 1.76], p< 0.001), compared to those without a PV (Table 1). Conclusions: After three years of longitudinal follow up of 2000 patients in this multicenter prospective cohort study, patients with a PV in a breast cancer susceptibility gene were more likely to undergo guideline concordant breast MRI compared to patients without a PV. Carriers of high-risk breast cancer gene PVs were over six times as likely to have undergone MRI compared to patients without PVs within the first three months after genetic results disclosure and counseling. These results demonstrate the effectiveness of MGPT and genetic counseling in guiding patients with PVs in breast cancer susceptibility genes to the appropriate adoption of guideline-concordant screening. Odds ratios of MRI screening in patients carrying PV in breast cancer risk genes. Odds in relation to patients who do not carry a PV High risk gene PV: BRCA1/2, CDH1, PALB2, TP53; Moderate Risk PV: CHEK2, ATM, NBN. Percent of patients having undergone an MRI at the specified time points High risk gene PV: BRCA1/2, CDH1, PALB2, TP53; Moderate Risk PV: CHEK2, ATM, NBN. Citation Format: Leah A. Naghi, Charite N. Ricker, Duveen Sturgeon, Julie Culver, Kerry Kingham, Rachel Hodan, Nicolette M. Chun, John Kidd, Joseph Bonner, Christine Hong, Meredith Mills, Sidney S. Lindsey, Kevin McDonnell, Uri Ladabaum, James M. Ford, Stephen Grube, Allison W. Kurian, Gregory E. Idos. Uptake of Breast Cancer MRI Screening in Patients After Multiplex Gene Panel Testing [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 P6-02-07.