Prognostic and predictive factors for primary chemotherapy in locally advanced breast cancer

Background Complete pathologic response (pCR) to neoadjuvant chemotherapy in breast cancer is associated to a better locoregional disease control and better long-term prognosis. Our purpose is to identify clinical and pathologic characteristics that influence treatment response, relapse risk and overall survival. Methods We analyzed 341 women with breast cancer submitted to primary chemotherapy between 2004 and 2017. We compared clinical response, pathologic response and conservative surgery rate, among different tumor and patient features. We assessed survival and relapse rate, according to complete pathologic response and histologic characteristics. Results Among 341 women who underwent neoadjuvant treatment, 34% obtained pCR and 94,4% expressed a pathologic response. Patients who achived pCR had better overall survival (HR 0,68, CI95% 0,53-0,87, p=0.002) and better progression free survival (HR 0,78, CI95%, 0,61-1,00, p=0,05). pCR was significantly influenced by histologic grade (0% G1, 18,9% G2 vs 41,5% G3, p-value <0,001), HER2 over-expression (56% vs 22,8%, p-value<0,001), cytokeratin 19 expression (38,6% vs 30,8%, p-value 0,047) and cytokeratin 5 (44% vs 32,4%, p-value 0,002). Instead, presence of bilateral breast cancer (34,7% vs 0%, p-value 0,007) and hormone receptor expression (20,2% vs 54,3%, p-value <0,001) negatively influenced pCR. Additionally, overall survival was negatively influenced by cytokeratin 19 expression (HR 0,14, CI95% 0,10-0,20, p<0,001) and presence of inflammatory breast cancer (HR 0,26, CI95% 0,11-0,64, p=0.003). Conclusions Cytokeratin 19 expression, cytokeratin 5 expression, histologic grade, molecular subtypes and bilaterality are independent predictors for pCR to primary chemotherapy. pCR influences positively overall survival and progression free survival. However, inflammatory carcinoma and cytokeratin 19 expression are independent predictors for a worse prognosis.