Cardiovascular Disease Risk of Left-Sided Breast Radiotherapy
Menée à partir de données canadiennes portant sur 76 586 patientes atteintes d'un cancer du sein traité par radiothérapie externe (âge moyen : 59 ans ; durée médiane de suivi : 10,9 ans), cette étude analyse l'association entre une irradiation du sein gauche et le risque de maladie cardiovasculaire à long terme
Radiotherapy is a cornerstone of curative-intent breast cancer care, but for decades left-sided breast cancer treatment has raised a specific survivorship concern: inadvertent cardiac irradiation and subsequent cardiovascular disease (CVD). In a population-based cohort study of 76 586 women treated with photon external beam radiation therapy (EBRT) in Ontario between 2002 and 2017, Nakajima et al compared outcomes after left- vs right-sided breast radiotherapy using linked administrative data. With a median follow-up of 10.9 years, the 15-year cumulative incidence of first cardiovascular hospitalization (International Statistical Classification of Diseases and Related Health Problems, Tenth Revision [ICD-10] codes I00-I78 as the most responsible diagnosis) was 13.8% after left-sided vs 13.5% after right-sided EBRT (P = .43), with an adjusted hazard ratio of 1.02 (95% CI, 0.98-1.06). All-cause mortality was essentially identical (26.1% vs 26.0%), and major adverse cardiovascular events did not differ. Small signals emerged in secondary analyses: among women without baseline CVD, new heart failure (10.2% vs 9.6%) and new ischemic heart disease (13.6% vs 12.8%) were slightly more frequent after left-sided EBRT, and when recurrent events were counted, left-sided disease was associated with a modestly higher CVD hospitalization rate (1.72 vs 1.63 per 100 person-years; hazard ratio, 1.05; 95% CI, 1.00-1.11).
JAMA Network Open , éditorial en libre accès, 2026