Abstract P3-01-09: Mri in the pre-operative workup of breast cancer patients

Abstract PurposeThe utility of pre-operative MRI (preop MRI) for patients with a new breast cancer diagnosis is controversial. Recently there has been increased use of routine MRI during preoperative workup to evaluate for areas necessitating additional biopsy and planning of operative resection extent; however, these practices carry the risk of delaying treatment, and subjecting patients to unnecessary biopsies and overly extensive resections. Triple negative breast cancer (TNBC) is more difficult to detect on mammography compared to non-TNBC, and patients with TNBC do not receive the chemoprevention benefits of adjuvant endocrine therapy; preop breast MRI to detect mammographically occult foci of disease may therefore be more relevant for patients with TNBC. MethodsOutcomes were evaluated for TNBC patients treated in the prospectively-maintained database of an academic cancer program in a metropolitan city of the Northeast, 1998-2018. ResultsOf 428 TNBC cases, 35.7% (153) had pre-op MRI. 43.6% (61) of 140 TNBC cases ≤50 years old had pre-op MRI compared to 31.9% of 288 TNBC cases >50 years old (p=0.016). There were no differences in race, or stage at presentation between those who had pre-op MRI and those who did not. 34% (52) of pre-op MRI TNBC cases underwent additional biopsies versus 0.43% (1) of TNBC patients who did not have pre-op MRI (p<0.0001). Average time to treatment was 29.5 days for pre-op MRI TNBC cases compared to 25 days for TNBC patients who did not have pre-op MRI (p=0.0026). 9.8% (15) of pre-op MRI TNBC cases underwent re-excisions versus 17.7% (41) of TNBC patients who did not have pre-op MRI (p=0.076). Of those who had mastectomies, patients who had pre-op MRI were more likely to have bilateral mastectomies (21.6% (33) pre-op MRI TNBC v 12.9% (30) of TNBC patients who did not have pre-op MRI (p=0.0471)). Five-year overall survival was no different between patients who had pre-op MRI and those who did not (95.2% vs 95.3% respectively; p=0.79). Among patients undergoing breast conserving surgery, there were no significant differences in the rates of local recurrence between patients that had preop MRI compared to those that did not (13.1% vs 9.1% p=0.392). ConclusionOur data demonstrated that preop MRI in TNBC patients was associated with additional biopsies, more extensive breast surgery, and longer time to treatment. Preop MRI had no impact on survival or local recurrence among patients undergoing breast conserving surgery. Citation Format: Solange Bayard, Genevieve Fasano, Yalei Chen, Jennifer Marti, Rache Simmons, Alexander Swistel, Michelle Drotman, Melissa Davis, Lisa Newman. Mri in the pre-operative workup of breast cancer patients [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-01-09.