Magnetic resonance imaging with concentric shrinkage as a prognostic factor in patients with luminal breast cancer during neoadjuvant chemotherapy

e11587 Background: The important characteristics of breast cancer is its tumor heterogeneity and response to neoadjuvant chemotherapy (NAC). We analyzed the patterns of tumor shrinkage as a prognostic indicator after NAC for luminal breast cancer. Methods and Results. Methods: Of 854 patients who had received NAC in the single institute between January 2000 and December 2009, 265 luminal breast cancerwere retrospevively examined. Luminal breast cancer was defined as ER and/or PgR positive in more than 10% of cancer cells and HER2 negative (IHC 0, 1+ or FISH ), strong ER/PgR positivity and concentric shrinkage as significantly favorable, and lymph node metastases as significantly unfavorable prognostic factors. Multivariate analysis for OS identified tumor size as significantly unfavorable prognostic factors(p=0.012). Conclusions: the tumor shrinkage pattern could be an important prognostic factor for luminal breast cancer and this suggests that a concentric shrinkage pattern of response may be infrequently associated with chemotherapy-resistant residual cancer cells.