Cardiovascular mortality among cancer survivors who developed breast cancer as a second primary malignancy
Menée à partir des données des registres américains des cancers portant sur 1 024 047 patientes ayant survécu à un cancer primitif du sein et sur 41 744 patientes ayant développé un second cancer du sein diagnostiqué entre 1975 et 2016, cette étude analyse, chez ces deux populations, la mortalité par maladie cardiovasculaire (durée de suivi : 994 415 911 personnes-années ; 5 403 551 décès par maladie cardiovasculaire)
Background : To assess the risk of cardiovascular mortality among cancer survivors who developed breast cancer as a second malignancy (BCa-2) compared with patients with first primary breast cancer (BCa-1) and the general population. Methods : Using the Surveillance, Epidemiology, and End Results database, we conducted a population-based cohort study including 1,024,047 BCa-1 and 41,744 BCa-2 patients diagnosed from the age 30 between 1975 and 2016, and the corresponding US female population (994,415,911 person-years; 5,403,551 cardiovascular deaths). Compared with the general population and BCa-1 patients, we calculated incidence rate ratios (IRRs) of cardiovascular deaths among BCa-2 patients using Poisson regression. To adjust for unmeasured confounders, we performed a nested, case-crossover analysis among BCa-2 patients who died from cardiovascular disease. Results : Although BCa-2 patients had a mildly increased risk of cardiovascular mortality compared with the population (IRR 1.08) and BCa-1 patients (IRR 1.15), the association was pronounced among individuals aged 30–49 years (BCa-2 vs. population: IRR 6.61; BCa-2 vs. BCa-1: IRR 3.03). The risk elevation was greatest within the first month after diagnosis, compared with the population, but comparable with BCa-1 patients. The case-crossover analysis confirmed these results. Conclusion : Our findings suggest that patients with BCa-2 are at increased risk of cardiovascular mortality.