2877 - Cardiovascular Events Following Radiotherapy for Oropharyngeal Cancer: Incidence, Risk Factors, and Timing of Events
Presenter(s)
A. Williams1, H. Mohammadi2, K. Wert2, Y. Zhao3, S. Li1, J. R. Janus4, S. Patel1, P. Pirgousis1, O. Okuyemi1, E. Liu1, L. E. Haydu5, and A. L. Holtzman2; 1Mayo Clinic Florida, Jacksonville, FL, 2Department of Radiation Oncology, Mayo Clinic, Jacksonville, FL, 3Department of Medical Oncology, Mayo Clinic Florida, Jacksonville, FL, 4Mayo Clinic, Department of Otolarynoglogy, Jacksonville, FL, 5Mayo Clinic, Jacksonville, FL
Purpose/Objective(s): Cardiovascular disease is the leading non-oncologic cause of death in cancer patients. Cancer-related hypercoagulability and intensive anti-neoplastic treatments can exacerbate cardiovascular risk factors. However, limited research has characterized cardiovascular morbidity following head and neck cancer therapy. This study assessed the incidence of cardiovascular events following radiotherapy (RT) for oropharyngeal cancer.
Materials/Methods: Under an IRB-approved protocol, we reviewed records of 240 patients with oropharyngeal cancer treated with RT at Mayo Clinic Florida (2016–2024). Cardiovascular events were defined as cerebrovascular accidents (including transient ischemic attack), deep vein thrombosis (DVT), pulmonary embolism (PE), or myocardial infarction (MI). Comorbidities, including BMI, smoking history, hypertension, hyperlipidemia, and diabetes, were assessed. Of 240 patients, 33 (13.8%) experienced 39 cardiovascular events. Additionally, 26 patients died from cancer or unrelated causes. A univariate Cox model evaluated associations between risk factors and time to a composite event (cardiovascular event or death), treating last follow-up as a censored value.
Results: With a median follow-up of 2 years (range: 0.03–7.3), the cumulative incidence of cardiovascular events was 13% at six months (95% CI: 9%–17%), 19% at one year (95% CI: 14%–24%), and 25% at two years (95% CI: 1%–31%). Among patients, 61% received primary RT to a median dose of 66 Gy, and 76% underwent bilateral neck irradiation. Of 39 cardiovascular events, 67% were acute, and 33% were late; 44% were grade 2, and 56% were grade 3 or higher. No grade 5 events occurred.
Increased age was significantly associated with cardiovascular events (OR = 1.03, 95% CI: 1.01–1.06, p = 0.018). Hyperlipidemia (OR = 1.81, 95% CI: 1.05–3.31, p = 0.033), diabetes (OR = 2.00, 95% CI: 1.11–3.60, p = 0.020), and prior heart disease (OR = 1.91, 95% CI: 1.09–3.37, p = 0.025) were significantly associated with increased cardiovascular event risk. Overweight BMI, hypertension, and smoking history were linked to higher risk but were not statistically significant.
Conclusion: Cardiovascular events occur in approximately 10% of patients within six months and 25% at two years post-RT. DVT was the most common event, followed by PE, emphasizing the need for early screening, particularly in the first six months. Despite high rates of bilateral neck irradiation, late cerebrovascular toxicity was rare. Longer follow-up is needed to better define long-term risks.