Impact of diabetes and other comorbidities on cardiovascular mortality in elderly breast cancer patients

Abstract

Breast cancer (BC), like most cancer, is a disease of aging. According to the Surveillance Epidemiology and End Results registry, the median age of BC diagnosis is 62 with 40% > 65 years, among whom 16% additionally suffer from diabetes mellitus (DM). As survival time increases with more effective treatment, CVD risk factors (CVDRF) are now increasing in this aging population. The aim of this study was to assess the impact of DM and other CVDRF on cardiovascular disease (CVD) mortality in elderly BC patients. This retrospective study included women aged > 55 who were initially diagnosed with BC recruited from the registry of the cardio-oncology unit of Casablanca, Morocco, from January 2014 to March 2021. Patients were divided into 4 categories: no comorbidity, DM only, DM and other comorbidity or other comorbidity without DM. Overall, 1843 patients with non-metastasized BC were included. Mean age of our series was 61.3 years, comorbidities at baseline prior to BC were: hypertension in 19.3%, DM in 9.8%, dyslipidemia in 11.8% and obesity in 10.4%. In our series, the short-term Overall survival (OS) was higher in patients with DM only compared with patients without comorbidity (HR: 1.16, 95% CI: 0.85–1.88) ( P = 0.037) and similar with those with other comorbidity without DM (HR: 0.76, 95% CI: 0.48–0.92) ( P = 0.066), while patients with DM and additional comorbidity had the worst short-term OS (HR: 1.82, 95% CI: 1.54–2.16) ( P < 0.001) especially in patients aged ≥ 75 years ( P = 0.028). In our study, among elderly BC patients, diabetes mellitus is associated with poorer prognosis and shorter OS compared to patients without any comorbidity, especially if associated with additional comorbidities such as hypertension, dyslipidemia and obesity. Larger registries to better understand the true incidence of CVD and the utility of current treatments would be invaluable for this growing population of breast cancer survivors.