J Breast Cancer.  2020 Jun;23(3):291-302. 10.4048/jbc.2020.23.e30.

Coronary Event Analysis in Breast Cancer Patients Who Received Breast-Conserving Surgery and PostOperative Radiotherapy: a Korean Nationwide Cohort Study

• Sung SY
• Lee JH
• Yang KH
• Seo Y
• Kang MY

• KMID: 2511785
• DOI: http://doi.org/10.4048/jbc.2020.23.e30

Abstract

Purpose
Adjuvant breast radiotherapy (RT) following breast-conserving surgery (BCS) has been reported to induce cardiac toxicity in breast cancer patients. We investigated the incidence and risk factors of major coronary events after breast RT using Korean nationwide Health Insurance Review and Assessment data.
Methods
Using data from a nationwide quality assessment of breast cancer treatment, we identified 3,251 patients who received breast RT after BCS in 2013. Data about major coronary events were additionally collected from national claims data. We defined major coronary events according to the International Classification of Diseases, 10th revision (ICD-10) codes I20-25.
Results
A total of 172 major coronary events (5.3%) occurred among 3,251 breast cancer patients. The 1-year, 2-year, and 3-year coronary event-free survival rates were 98.1%, 96.4% and 95.2%, respectively. Patients with underlying diabetes mellitus (88.6% vs. 95.7%, p < 0.001), high blood pressure (HBP) (89.4% vs. 96.3%, p < 0.001), and cerebrovascular accident (CVA) (84.0% vs. 95.4%, p < 0.001) showed significantly worse 3-year coronary event-free survival rates than those without comorbidities. Multivariate analysis revealed that patient age (p < 0.001), HBP (p < 0.001), CVA (p = 0.025), adjuvant hormonal therapy (p = 0.034), and Herceptin therapy (p < 0.001) were significantly associated with major coronary events in breast cancer patients.
Conclusion
The incidence of major coronary events after breast RT may be higher in breastcancer patients with risk factors such as underlying HBP or CVA, or who were in receipt of adjuvant Herceptin therapy. Heart-sparing RT techniques or intensity-modulated RT should be considered for breast-cancer patients with risk factors for heart toxicity.

Keyword

Breast neoplasms; Coronary artery disease; Radiotherapy; Risk factors