The association of preoperative MRI with surgical decision-making in patients with early-stage breast cancer: A multi-institutional analysis

Abstract Background: Lumpectomy with radiation (breast conservation) and mastectomy have equivalent overall survival. However, recent studies suggest that patients undergoing breast conservation have lower rates of recurrence compared to those undergoing mastectomy. A 2013 meta-analysis by Houssami, et al. found that the rate of mastectomy in patients who had preoperative MRI was 16%, twice as high as that in patients who did not have preoperative MRI. A multi-institutional analysis was performed to investigate the possible impact of modern MRI on the surgical management of early-stage breast cancer (ESBC). Methods: A retrospective comparative cohort study included patients with in-situ and invasive breast cancer eligible for breast conservation surgery from two institutions (NY and FL). Patients who received preoperative systemic therapy were excluded. Eligibility for breast conservation was defined as clinical stage Tis-2. Risk factors for the bilateral or multicentric disease were compared between the two groups including breast density, menopausal status, and concerning family history. The rate of ipsilateral mastectomy in lumpectomy-eligible women was compared between patients who did and did not receive preoperative MRI. Chi-square analysis was used to compare rates between groups. P values <0.05 were considered statistically significant. Results: 505 patients diagnosed between 1/2016-4/2019 (NY) and 2/2020-12/2020 (FL) underwent primary surgery for ESBC. 434 did not receive neoadjuvant therapy and were included in the analysis. 292 (67.3%) had preoperative MRI. There was no difference in the proportion of patients who were premenopausal or who met the criteria for genetic testing by family history. The largest dimension on preoperative imaging was similar between the two groups. Patients who had MRI were younger (median age 58 vs. 68, p<0.001) and more likely to have group 3 or 4 breast density (64.5% vs. 27.1%, p<0.001). Patients who underwent preoperative MRI were twice as likely to undergo mastectomy as their first surgery (32.6% vs. 15.3%, p<0.001). The rate of re-excision was similar between the two groups (MRI 13.0% vs. no MRI 10.8% p=0.511). Of note, the final pathologic size of the invasive or in-situ component was similar between the two groups (Table 1). Conclusion: Younger age and greater breast density are associated with preoperative MRI receipt and all three factors likely play a role in choosing mastectomy. Young women with dense breasts represent a unique cohort of patients that may be particularly susceptible to cancer-related worry and anxiety related to additional biopsies, and therefore may be more likely to opt against continued breast imaging. Since approximately 70% of patients with ESBC undergo preoperative MRI, future work should focus on mitigating these challenges to improve shared decision-making. Table 1.Comparison of ESBC Patients Who Did and Did Not Receive MRIMRI (n=292) %, median (IQR)No MRI (n=142)%, median (IQR)p-valueAge58 years (50-65)68 years (60-76)<0.001bPremenopausal27%21%0.108Dense Breasts65%27%<0.001bMeet Criteria for Genetic Testing40%38%0.207Imaging Size13 mm (9-21)12 mm (8-20)0.315Mastectomy as First Surgery33%15%<0.001bPlan for Repeat Surgerya20%24%0.402Re-excision13%11%0.511Pathologic Size (Invasive)13 mm (8-20)13 mm (9-22)0.482Pathologic Size (DCIS)10 mm (5-20)8 mm (3-15)0.093aRepeat surgery includes re-excision, completion mastectomy, and axillary dissectionbDenotes significant p-values. Citation Format: Peter A Borowsky, Seraphina Choi, Orly Morgan, Amy K White, Claudya Morin, Jose Net, Susan Kesmodel, Neha Goel, Yamini Patel, Alexa Griffiths, Joshua A Feinberg, Aaron Kangas-Dick, Charusheela Andaz, Christina Giuliano, Natalie Zelenko, Donna-Marie Manasseh, Patrick Borgen, Kristin E Rojas. The association of preoperative MRI with surgical decision-making in patients with early-stage breast cancer: A multi-institutional analysis [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 P3-03-20.