Disparities in mortality among HER2-positive breast cancer patients treated with trastuzumab in Chile (2015-2024): real-world evidence from 4,920 cases.

BACKGROUND

HER2-positive breast cancer (BC) is an aggressive subtype that affects approximately 15-25% of patients.

OBJECTIVE

This study aimed to identify sociodemographic factors associated with mortality among patients with HER2-positive BC treated with trastuzumab under the Ricarte Soto Law (RSL) in Chile between 2015 and 2024.

METHODS

A cross-sectional observational design was used, based on a national database including 4,920 patients who accessed treatment through the RSL. Bivariate and multivariate logistic regression models were applied to evaluate factors associated with mortality.

RESULTS

Older age, public healthcare system, and residence outside the Metropolitan Region were associated with higher mortality. These findings suggest that disparities in outcomes persist despite financial coverage of high-cost therapies, indicating the influence of structural and geographic factors on cancer care.

CONCLUSIONS

This study provides real-world evidence to inform policies aimed at reducing inequities in access and outcomes among patients with breast cancer in Chile.