Abstract P3-02-01: Pre-operative breast MRI would not benefit breast cancer patients' survival, even in young patients treated with breast-conservative surgery
Authors: Huang N , Chen J , Yang B , Quan C , Xue J , Huang X , Wu J 
Published: May 2019

Abstract
Background
Although breast magnetic resonance imaging (MRI) could help to identify occult lesions in breast cancer, its role in patient outcome has always been controversial. The current study aimed to evaluate the role of MRI in Asian breast cancer patients, especially young patients that might have dense breasts.
Methods
Patients with non-metastatic unilateral breast cancer who received surgery in our institute during 2007-2013 were retrospectively reviewed. The differences between groups were compared using Pearson's χ2 test.Loco-regional recurrence-free survival (LRRFS) and recurrence-free survival (RFS) were estimated using the Kaplan-Meier method.
Results
A total of 13,681 patients were included into analysis, among which 5823 (42.6%) had pre-operative MRI. Of all patients, 39.7% were stage 0-I according to TNM system, 35.5% were stage II, 14.8% were stage III and 10.0% could not be staged. Patients with axillary lymph node metastasis were comparable in MRI and non-MRI groups (35.3% versus 35.6%, P=0.695). The percentile of patients receiving MRI increased from 7.3% in 2007 to 67.5% in 2013. Patients in the breast-conservative surgery (BCS) group were more likely to receive MRI compared with the mastectomy group (P&lt;0.001).
Age and menopausal status were also related with the choice of pre-operative MRI. When patients were grouped according to age, 56.7%, 48.9%, 43.6%, 37.0% and 27.1% patients in the ≤35, 36-45, 46-55, 56-65 and &gt;65 years old group had MRI, respectively (P&lt;0.001). When patients were grouped according to menopausal status, 37.8%, 48.8% and 27.3% patients in the post-menopausal group, pre-menopausal group and unknown menopausal status group had MRI, respectively (P&lt;0.001).
In survival analysis, the average follow-up time for the MRI group (N=5823) and non MRI group (N=7858) were 88.5 and 114.4 months, during which 238 (4.1%) and 464 (5.9%) breast cancer recurrences occurred, while 63 (1.1%) and 159 (2.0%) loco-reginal recurrences occurred. The estimated 5-year RFS for MRI group and non-MRI group were 90.1% and 90.0% (P=0.510). The 5-year LRR-free survival LRRFS for MRI group and non-MRI group were 96.7% and 97.3% (P=0.128). In subgroup analysis, 2376 patients received BCS, and 11,035 received mastectomy. Patient in the pre-operative MRI group did not have superior RFS or LRRFS compared with the non-MRI group, regardless of surgical management (BCS versus mastectomy). Then we restrained the analysis to patients who were ≤45 years old and treated with BCS. A total of 699 patients had pre-operative MRI, and 419 patients did not. The 5-year RFS for MRI group and non-MRI group were 95.8% versus 94.6% (P=0.231); the 5-year LRRFS for MRI group and non-MRI group were 99.8% and 97.1% (P=0.144).
Conclusions
There was an increasing trend of pre-operative MRI examination during 2007-2013, especially in young patients and patients treated with BCS. However, pre-operative MRI could not benefit breast cancer patients' survival by detecting occult lesions, even in young patients treated with BCS, who were considered to have dense breasts.
Citation Format: Huang N, Chen J, Yang B, Quan C, Xue J, Huang X, Wu J. Pre-operative breast MRI would not benefit breast cancer patients' survival, even in young patients treated with breast-conservative surgery [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-02-01.