Cardiotoxicity of some medical anti-cancer treatments and radiotherapy for breast cancer (BC) patients is well known, but knowledge for conduction disorders or sinus node disease remains poor.

To examine the risk of pacemaker (PM) implantation subsequent to BC treatment by comparing PM incidence in BC patients to that in the general population on an age-specific basis.

Our study was based on the Échantillon généraliste de bénéficiaires (EGB), the 1/97 random sample, the French nationwide health database (SNDS). The study population consisted of adult women treated for a primo BC between 2008 and 2014, with no previous history of PM implantation, followed until 2016. For each year from 2008 to 2016, the reference population included all women present in the EGB with no PM or BC implantation. PM implantations were identified according to the Classification commune des actes médicaux. The standardised incidence ratio (SIR) was calculated as the ratio of the observed number of PM in the BC population to the expected number of PM computed using annual age-specific PM incidence rates from the reference population, weighted according to the age structure of the BC population.

Between 2008 and 2016, the annual reference population consisted of nearly 193,000 individuals with an incidence rate of PM implantation that varied from 1case/100,000 in the younger category (<40 years) to 552 cases/100,000 for women ≥85 years. The BC population included 2821 patients (approximately 400 per year, 50% aged>60 years) in whom 18 PM implantations were observed compared with 11.5 expected yielding a SIR of 1.56 (95% CI: 0.93–2.36), indicating a 56% higher incidence of PM in the BC population.

These preliminary results indicate that treatment for BC may be associated with an increased risk of PM implantation. Further analysis according to the type of treatment (radiotherapy, chemotherapy…) is ongoing.