RESUMO
Background: Breast cancer (BC) is the malignant tumour that has been most frequently diagnosed, being the second most common cancer worldwide and the most frequent in women. Objective: To analyse the probability of 5-year overall survival according to age, stage of disease, immunohistochemical subtype, histological grade and histological type in patients with BC. Methodology: Operational research that used a cohort design of patients diagnosed with BC at the SOLCA Núcleo de Loja-Ecuador Hospital from 2009 to 2015 and with follow-up until December 2019. Survival was estimated with the actuarial method and Kaplan-Meier method, and, for multivariate analysis, the proportional hazards model or Cox regression was used to estimate the adjusted Hazard Ratios (HRs). Results: Two hundred and sixty-eight patients were studied. Mean overall survival was 4.35 years (95% confidence interval (95% CI): 40.20-4.51) and 66% survived to 5 years. The main predictors of survival were advanced stage of disease (III-IV) (HR = 7.03; 95% CI: 3.81-12.9); patients human epidermal growth factor receptor 2-neu (HER2-neu) overexpressed (HR = 2.26; 95% CI = 1.31-4.75) and triple negative (HR = 2.57; 95% CI = 1.39-4.75). The other variables were not significant. Conclusions: The results show a higher mortality associated with higher clinical stage, more aggressive histological grades and immunohistochemical subtype HER2-neu overexpressed and triple negative tumours.