Abstract P5-04-06: Breast Imaging Recommendations for Females &lt;40 Years of Age with ≥20% Lifetime Breast Cancer Risk: Practice Patterns at a Specialized Clinic
Authors: Wehbe Alexandra , Laws Alison , Katlin Fisher , Sharma Eshita , Hans Marybeth , Graichen Mary , Bychkovsky Brittany , Scheib Rochelle , Garber Judy , Pace Lydia , King Tari 
Published: March 2023

Background— There are limited data to guide breast cancer screening recommendations among females &lt; 40 yrs of age with elevated lifetime breast cancer risk not driven by a known germline mutation. The American Cancer Society recommends initiating screening at age 30, while the National Comprehensive Cancer Network (NCCN) recommends 10 yrs younger than the youngest affected relative (YAR). Both support screening MRI in addition to annual mammogram (MMG). This study describes practice patterns related to screening imaging recommendations and patient (pt) follow-through in young females with ≥20% lifetime breast cancer cared for in a specialized clinic.

Methods— At the Brigham and Women’s Hospital high-risk breast clinic, specialized advanced practice providers, surgeons and oncologists perform risk assessment including use of the Tyrer-Cuzick (TC) risk model, and provide risk management recommendations. For this study, we identified pts age&lt; 40 yrs with &gt;20% lifetime breast cancer risk, no known genetic mutation or high-risk breast lesions, and ≥1 first or second-degree relatives (FDR or SDR) with breast cancer. We evaluated factors associated with recommendation for i) early screening initiation, defined as prior to age 40, and ii) use of supplemental imaging modalities.

Results—335 pts met study criteria: 20% were age&lt; 30, 36% were 30-34, and 44% were 35-39. Mean lifetime risk by the TC model was 32% (SD: 10%). Early screening was recommended in 75%; these pts were more likely to have an affected FDR (71% vs. 48%, p&lt; 0.001) and younger affected relatives (median age of YAR: 44 vs. 55, p&lt; 0.001). Among pts whose YARs were age&lt; 50, early screening was recommended in-line with NCCN guidelines for 99% of pts with FDRs&lt; 50 vs. 80% of pts with only SDRs&lt; 50 (p&lt; 0.001). Among pts whose YARs were age≥50, early screening was recommended contrary to NCCN guidelines in 51%. Factors associated with an early screening recommendation in this subgroup were having received a prior MMG (62% recommended early screening vs. 33% with no prior MMG) as well as being older at time of risk discussion (median age 37 in early screening group vs. 34 in routine screening group) and having younger affected relatives (median age of YAR: 53 vs. 56) (all p≤0.01). Regarding use of supplemental imaging, 35% were recommended screening MMG alone, while 65% were also offered screening MRI or ultrasound (US). Factors most strongly associated with offering MRI/US included having heterogeneously or extremely dense breasts, normal BMI, greater extent of family history, younger affected relatives and higher TC scores (Table). All except extent of family history remained statistically significant in multivariable analysis. Among those offered supplemental MRI/US who were eligible to initiate screening, 48% had pursued MRI, 7% US +/- MRI, 27% MMG alone, and 18% had no screening imaging at a median follow-up of 17 months.

Conclusions— These data suggest that providers in our high-risk breast clinic are using nuanced clinical judgment related to screening recommendations in pts &lt; 40 yrs with elevated lifetime risk. Those with affected FDRs at age&lt; 50 were consistently recommended early screening initiation, while practice recommendations varied more for pts with only SDRs age&lt; 50 or those with YAR age≥50, suggesting a need for consensus criteria as to when to initiate screening in these subgroups. Multiple factors impacted recommendations for screening MRI/US, most notably breast density.

Factors associated with offering supplemental screening with MRI/US

Citation Format: Alexandra Wehbe, Alison Laws, Fisher Katlin, Eshita Sharma, Marybeth Hans, Mary Graichen, Brittany Bychkovsky, Rochelle Scheib, Judy Garber, Lydia Pace, Tari King. Breast Imaging Recommendations for Females &lt;40 Years of Age with ≥20% Lifetime Breast Cancer Risk: Practice Patterns at a Specialized Clinic [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 P5-04-06.