RESUMEN
Abstract Objective To identify the biomarkers of response to neoadjuvant chemotherapy in early luminal breast cancer. Methods A cross-sectional study that included all patients with early or locallyadvanced luminal breast cancer submitted to neoadjuvant chemotherapy between 2013 and 2014. Demographic, clinic and pathologic data were retrieved from patient records. The expressions of the estrogen receptor (ER), the progesterone receptor (PR), and Ki67 were analyzed by immunohistochemistry (IHC). The status of the human epidermal growth factor receptor 2 (HER2) was evaluated by IHC and fluorescent in situ hybridization (FISH). Independent predictors of clinic and pathologic response were evaluated by stepwise logistic regression models and receiver operating characteristic (ROC) curve analysis. Results Out of 298 patients identified, 115 were included in the analysis. Clinical complete response (cCR) was observed in 43.4% of the patients (49/113), and pathologic complete response (pCR) was observed in 7.1% (8/115) of the patients. The independent predictors of cCR were premenopausal status (p < 0.001), low PR expression (≤ 50% versus > 50%; p = 0.048), and Ki67 expression ≥ 14% (versus < 14%; p = 0.01). Patients with cCR were more commonly submitted to breast conserving surgery (34.7% versus 7.8%; p < 0.001). Increasing cut-off points for Ki67 expression were associated with an increase in specificity and a decrease in sensitivity to identify patients with cCR. Conclusion Premenopausal status, lower PR expression and higher Ki67 expression were associated with a higher rate of cCR to neoadjuvant chemotherapy in luminal breast cancer.
Resumo Objetivo Identificar biomarcadores de resposta à quimioterapia neoadjuvante em câncer luminal de mama. Métodos Estudo transversal em que foram incluídas todas as pacientes com câncer luminal de mama em estádio inicial ou localmente avançado que foram submetidas a quimioterapia neoadjuvante nos anos de 2013 e 2014. Dados demográficos, clínicos e patológicos foram obtidos de prontuários médicos. As expressões de receptor de estrogênio (RE), de receptor de progesterona (RP), e de Ki67 foram avaliadas por imuno-histoquímica (IHQ). A expressão do receptor tipo 2 do fator de crescimento epidérmico humano (human epidermal growth factor receptor 2, HER2) foi avaliada por IHQ e hibridização in situ por imunofluorescência (HISI). Análises de regressão logística e de curva de característica de operação do receptor (COR) foram usadas para investigar fatores preditivos independentes de resposta clínica e patológica. Resultados De 298 pacientes identificadas, 115 foram incluídas na análise. Resposta clínica completa (RCc) foi observada em 43.4% das pacientes (49/113), e resposta patológica completa (RPc), em 7.1% (8/115). Os fatores preditivos independentes de RCc foram status menopausal (p < 0.001), baixa expressão de RP (≤ 50% versus > 50%; p = 0.048), e expressão de Ki67 ≥ 14% (versus < 14%; p = 0.01). Pacientes com RCc apresentaram maior probabilidade de serem submetidas a cirurgia conservadora da mama (34.7% versus 7.8%; p < 0.001). Aumento no ponto de corte para expressão de Ki67 foi associado a aumento da especificidade e redução da sensibilidade na identificação de pacientes com RCc. Conclusão Status premenopausal, baixa expressão de RP e maior expressão de Ki67 estiveram associados a maior taxa de RCc à quimioterapia neoadjuvante no câncer luminal de mama.