Determinants of survival in women diagnosed with breast cancer between 2008 and 2017: An analysis of a cohort using data from four Population-Based Cancer Registries of Colombia.

Background: Breast Cancer (BC) is the leading cause of cancer-related mortality in women, especially in low- and middle-income countries. Population-Based Cancer Registries (PBCRs) play a crucial role in monitoring cancer trends and guiding evaluation and planning of cancer control programs. In Colombia, there are no national analyses of BC survival. The aim was to estimate the overall survival up to 5-year of women diagnosed with BC, as well as its determinants, in Colombia using population-based data from four Colombian PBCRs.

Methods: We conducted a cohort study with women diagnosed with invasive BC between 2008 and 2017, identified by the corresponding PBCRs as residents of the Colombian cities of Barranquilla, Bucaramanga metropolitan area, Manizales, and Pasto. We performed follow-up up to 5 years after the BC diagnosis, or until death (all-cause). We estimated the overall survival (Kaplan Meier). We evaluated the simultaneous effect of multiple risk factors on death risk using Cox proportional hazards analysis, obtaining adjusted Hazard Ratios (aHR) and Confidence Intervals (CI).

Results: The analysis cohort included 8020 BC cases. The observed overall survival was 72.5 %. The likelihood of 5-year survival was lowest for women aged 70 or older (aHR 1.61; 95 % CI 1.42-1.83), those living in a middle Socioeconomic Stratum (SES) (aHR 1.32; 95 % CI 1.05-1.66), those affiliated to the subsidized Health Insurance Regime (HIR) (aHR 1.47; 95 % CI 1.32-1.63), and those diagnosed in stages III-IV (aHR 2.29; 95 % CI 2.03-2.57) compared to women with a diagnosis age between 50 and 70 years, residents in high SES, those affiliated to the contributory HIR, and those diagnosed at stages I-II, respectively.

Conclusion: Social disparities are linked to BC survival in Colombia, likely due to limited access to healthcare services. This suggests the importance of strengthening screening and diagnostic care, especially for vulnerable populations.