Resonancia magnética en el cáncer de mama tratado con neoadyuvancia: correlación radiopatológica de la respuesta y supervivencia libre de enfermedad en función del subtipo molecular

Abstract

ObjectivesTo evaluate the radiologic and pathologic responses to neoadjuvant chemotherapy and their correlation in the molecular subtypes of breast cancer and to analyze their impact in disease-free survival. Material and methodsWe included 205 patients with breast cancer treated with neoadjuvant chemotherapy. We evaluated the radiologic response by comparing MRI images acquired before and after chemotherapy. The pathologic response was classified on the Miller and Payne scale. For each subtype (HER2+, TN, luminal A, luminal B HER2–, and luminal B HER2+), we used the χ2 test, Student's t-test, ANOVA, and Kendall's Tau-b to evaluate the radiologic response and the pathologic response, the radiologic-pathologic correlation, and the disease-free survival. ResultsThe subtypes HER2+ (62.1%) and TN (45.2%) had higher rates of complete radiologic response. The pathologic response was 65.5% in the HER2+ subtype, 38.1% in the TN subtype, 2.6% in the luminal A subtype, 8.2% in the luminal B HER2– subtype, and 31% in the luminal B HER2+ subtype. The rate of radiologic-pathologic correlation was significant in all subtypes, higher in TN and HER2 (Tau-b coefficients 0.805 and 0.717, respectively). Disease-free survival was higher in HER2+ (91.9±3.3 months) and lower in TN (69.5±6.3 months), with significant differences between the cases with poor and good radiologic responses (P=.040). Survival was greater in cases with good radiologic response, except in cases with luminal A subtype. ConclusionMRI can be a useful tool that provides information about the evolution of breast cancer treated with neoadjuvant chemotherapy, which varies with the immunohistochemical subtype.