Background: Breast cancer (BC) is the most common neoplasm among women in Colombia. Colombian guidelines recommend screening women aged 50 to 69 years with biannual mammography, yet adherence to screening or its impact on mortality at a national level have not been assessed. We aimed to determine adherence to BC screening guidelines and its association with 3-year overall survival in women treated for BC in 2015 in Colombia.

Methods: We conducted a national retrospective cohort study based on administrative claims from the Colombian contributory health regime and the national mortality database. We identified patients eligible for BC screening between 2011-2014 who were first treated for BC in 2015 through a previously validated BC case detection algorithm combining ICE-10 and oncologic procedure codes. Screened patients were those who had at least two mammography codes separated by at least two years. Primary outcome was 3-year survival. We used propensity score methods to balance sociodemographic and clinical covariates and performed a Cox regression with the matched sample to estimate hazard ratios (HR).

Results: 1520 patients were identified. 265 (17.43 %) patients were screened according to guidelines. Mean age was 62.50 (SD 4.66) for screened and 61.83 (SD 4.60) for unscreened patients. Regions with lowest adherence to screening were Pacific (9.06%) and Oriental (9.06%). Mortality rates were 2.64 (CI95% 1.88-3.72) and 4.36 (CI95% 3.85 – 4.95) per 100 person-years, respectively. Adherence to guideline screening recommendations was associated with an improved 3-year survival (HR:0.55 (CI95% 0.37-0.80), and HR:0.58 (CI95% 0.40-0.84) in the unmatched and matched samples, respectively).

Conclusion: BC screening is associated with increased survival in women treated for BC in Colombia. Adherence to BC screening guidelines is low and heterogenous between regions. BC screening adherence can be monitored through administrative claims, and it could become a national indicator of care for women with BC.