Mortality and Major Adverse Cardiac Events in Patients With Breast Cancer Receiving Radiotherapy: The First Decade.

Area of Science:

• Cardio-oncology
• Radiotherapy
• Cardiovascular Medicine

Background:

• Radiotherapy is a common breast cancer (BC) treatment.
• Current guidelines suggest cardiac adverse event screening 10 years post-radiotherapy, but the rationale is unclear.

Purpose of the Study:

• To investigate cardiovascular event rates in the first decade after curative radiotherapy for BC.
• To compare mortality and cardiovascular event rates in BC patients with a matched control population.

Main Methods:

• A cohort of 1095 BC patients (mean age 56±12 years) was analyzed.
• Mortality and cardiovascular event rates were compared to an age- and risk factor-matched control group.
• Risk factors for mortality and major adverse cardiac events were identified.

Main Results:

• Heart failure (RR, 1.97) and atrial fibrillation/flutter (RR, 1.82) were more frequent in BC patients compared to controls.
• Age, tumor grade, and neoadjuvant treatment were risk factors for mortality.
• Age, mean heart dose, prior cardiovascular disease, and Mayo Clinic Cardiotoxicity Risk Score predicted major adverse cardiac events.

Conclusions:

• While cancer-related mortality dominated, heart failure and atrial fibrillation/flutter were prevalent within the first decade post-radiotherapy for unilateral BC.
• Mean heart dose and pre-existing cardiovascular conditions are key risk factors for cardiac events.
• These findings support the need for early, specialized cardio-oncology follow-up after radiotherapy.