Association of cancer treatment with excess heart age among five-year young breast cancer survivors

Purpose Data evaluating cardiovascular disease (CVD) risk by cancer treatment among young women (≤ 40 years) with breast cancer are limited.

Methods Among 372 five-year breast cancer survivors aged 30–40 years from the Young Women's Breast Cancer Study, we assessed the association of cancer treatments (anthracyclines, trastuzumab, radiation/laterality, endocrine therapy) and excess heart age (difference between predicted 10-year CVD risk as assessed by adapted Framingham Risk Score and chronological age), prevalent elevated excess heart age (≥ 2 years), and worsening excess heart age (change of ≥ 2 excess heart age years) at breast cancer diagnosis and two- and five-year follow-up using multivariable linear and logistic regressions.

Results Most women had stage I or II (79%), ER + (71%), or PR + (65%) breast cancer.

At diagnosis, women had little excess heart age by treatment receipt (range of means = -0.52,0.91 years).

Left-sided radiation (β = 2.49,SE = 0.96,p = 0.01) was associated with higher excess heart age at five-year follow-up.

For prevalent elevated excess heart age (two-year = 26%;five-year = 27%), women treated with right-sided radiation had increased risk at two-years (OR = 2.17,95%CI = 1.12–4.19), yet at five-years, associations were observed after any radiation (OR = 1.92,95%CI = 1.09–3.41), especially after left-sided (OR = 2.13,95%CI = 1.09–3.41) radiation.

No associations were observed between systemic treatments and prevalent elevated excess heart age or any treatments with worsening excess heart age.

Conclusions Among young breast cancer survivors, radiation, but not other cancer treatments, was associated with elevated excess heart age.

Implications for cancer survivors CVD risk tools that incorporate cancer treatment, such as radiation, are needed to identify high risk young breast cancer survivors given the long survivorship and long latency of cardiovascular disease.