Overall survival in breast cancer patients: analysis of a 27- year historical cohort

Abstract

Background: This study aimed to analyzed overall survival and prognostic factors in a 27-year historical cohort of women with breast cancer in the Brazilian city of Goiânia. Methods: This retrospective cohort study used data from the population-based cancer registry in Goiânia, Goiás, Brazil, to evaluate overall survival between 1988 and 2015. Survival curves were constructed using the Kaplan-Meier method and compared with the log-rank test. Multivariate Cox regression analysis was performed to evaluate predictors of survival, with significance established at p<0.05. Results: The most common age group among the 7,395 women included in this study was 50-69 years (45.4%). The majority had localized breast cancer (62.4%) and the luminal A subtype (50.1%). The median survival was 122 months, with a 5-year overall survival rate of 83.1% and a 10-year overall survival rate of 65.5%. When evaluating ethnicity, survival was found to be greater for among white women compared to black women (mean of 120 months versus 110 months). In the Cox regression analysis, the following factors were found to be associated with decreased overall survival: age >70 years (HR: 1.33; p<0.001), histologic grade III (HR: 1.21; p=0.042), estrogen receptor-negative breast cancer (HR: 1.26; p=0.010), progesterone receptor-negative breast cancer (HR: 1.47; p=0.041), triple-negative subtype (HR: 2.36; p=0.008) and regional disease extension (HR: 1.73; p=0.023) or metastasis (HR: 2.67; p=0.012). Conclusion: During the study period, the overall survival rate in this cohort of women with breast cancer was 83.1% at five years and 65.5% at ten years. Different clinical, biological and tumor-related factors significantly affected prognosis in this population.