Background: Neoadjuvant chemotherapy (NCT) downstages advanced primary tumors, with magnetic resonance imaging (MRI) being the most sensitive imaging predictor of response. However, the impact of MRI evaluation on surgical treatment decisions in the neoadjuvant setting has not been well described. We report surgical patterns of care across 8 National Cancer Institute comprehensive cancer centers in women receiving both NCT and MRI to evaluate the impact of MRI findings on surgical planning.
Methods: Seven hundred seventy women from 8 institutions received NCT with MRI obtained both before and after systemic treatment. Univariate and multivariate analyses of imaging, patient-, and tumor-related covariates associated with choice of breast surgery were conducted.
Results: MRI and surgical data were available on 759 of 770 patients. A total of 345 of 759 (45 %) patients received breast-conserving surgery and 414 of 759 (55 %) received mastectomy. Mastectomy occurred more commonly in patients with incomplete MRI response versus complete (58 vs. 43 %) (p = 0.0003). On multivariate analysis, positive estrogen receptor status (p = 0.02), incomplete MRI response (p = 0.0003), higher baseline T classification (p < 0.0001), younger age (p < 0.0006), and institution (p = 0.003) were independent predictors of mastectomy. A statistically significant trend toward increasing use of mastectomy with increasing T stage at presentation (p < 0.0001) was observed in patients with incomplete response by MRI only. Among women with complete response on MRI, 43 % underwent mastectomy.
Conclusions: Within a multi-institutional cohort of women undergoing neoadjuvant treatment for breast cancer, MRI findings were not clearly associated with extent of surgery. This study shows that receptor status, T stage at diagnosis, young age, and treating institution are more significant determinants of surgical treatment choice than MRI response data.