Abstract 3743: Magnetic resonance imaging shrinkage patterns after neoadjuvant chemotherapy for breast carcinomas: Correlation with molecular subtypes

Abstract

Abstract Background: Neoadjuvant chemotherapy (NAC) is widely performed for patients with locally advanced breast carcinomas. It is important to obtain precise information using imaging modalities about the distribution of residual carcinomas after NAC to predict the success of breast conserving surgery. However, the relationship between magnetic resonance imaging (MRI) shrinkage patterns and molecular subtypes of breast carcinomas has not yet been investigated. Methods: We analyzed the MRI shrinkage and pathological patterns of residual carcinomas after NAC in 54 consecutive breast carcinomas. The shrinkage patterns were classified into five categories: Type I and II (concentric shrinkage with or without any surrounding lesion), type III (shrinkage with residual multinodular lesions), type IV (diffuse contrast enhancement in the entire quadrant), and non-visualization. Results: The most common MRI shrinkage pattern was type I (39%) followed by non-visualization (26%). The most common pathological shrinkage pattern was type III (33%), followed by type II (28%) and non-visualization (22%). The concordance rates of the MRI patterns of non-visualization and type I were significantly lower than those of the MRI patterns of type II, III, and IV (p = 0.018). Moreover, in the luminal subtypes, the concordance rates of the MRI patterns of non-visualization and type I were significantly lower than those of the MRI patterns of type II, III, and IV (p = 0.026); however, in the non-luminal subtypes, this correlation was not significant. Conclusions: The results of the present study suggest that the cases with MRI shrinkage patterns of non-visualization and type I require caution regarding the surgical margins compared with the other types, especially the luminal subtypes. Citation Format: Tsuyoshi Mori, Kaori Tomida, Mina Kitamura, Sachiko Sakai, Yuki Kawai, Tomoharu Shimizu, Tomoko Umeda, Tomoyuki Ueki, Sachiko Kaida, Toru Miyake, Hiroya Iida, Hiroya Akabori, Naomi Kitamura, Tsuyoshi Yamaguchi, Hiromichi Sonoda, Shigeyuki Naka, Masaji Tani. Magnetic resonance imaging shrinkage patterns after neoadjuvant chemotherapy for breast carcinomas: Correlation with molecular subtypes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3743. doi:10.1158/1538-7445.AM2017-3743