Cardiovascular effects of radiotherapy on the patient with cancer

Fullerenols Mitigate Radiation-Induced Myocardial Injury

Radiation-induced heart disease is a serious side effect of radiation therapy that can lead to severe consequences. However, effective and safe methods for their prevention and treatment are presently lacking. This study reports the crucial function of fullerenols in protecting cardiomyocytes from radiation injury. First, fullerenols are synthesized using a simple base-catalyzed method. Next, the as-prepared fullerenols are applied as an effective free radical scavenger and broad-spectrum antioxidant to protect against X-ray-induced cardiomyocyte injury. Their ability to reduce apoptosis via the mitochondrial signaling pathway at the cellular level is then verified. Finally, it is observed in animal models that fullerenols accumulate in the heart and alleviate myocardial damage induced by X-rays. This study represents a timely and essential analysis of the prevention and treatment of radiological myocardial injury, providing new insights into the applications of fullerenols for therapeutic strategies.

The Inverse Correlation Between the Duration of Lifetime Occupational Radiation Exposure and the Prevalence of Atrial Arrhythmia

Objective

Advancements in fluoroscopy-assisted procedures have increased radiation exposure among cardiologists. Radiation has been linked to cardiovascular complications but its effect on cardiac rhythm, specifically, is underexplored.

Methods

Demographic, social, occupational, and medical history information was collected from board-certified cardiologists via an electronic survey. Bivariate and multivariable logistic regression analyses were performed to assess the risk of atrial arrhythmias (AA).

Results

We received 1,478 responses (8.8% response rate) from cardiologists, of whom 85.4% were male, and 66.1% were ≤65 years of age. Approximately 36% were interventional cardiologists and 16% were electrophysiologists. Cardiologists > 50 years of age, with > 10,000 hours (h) of radiation exposure, had a significantly lower prevalence of AA vs. those with ≤10,000 h (11.1% vs. 16.7%, p = 0.019). A multivariable logistic regression was performed and among cardiologists > 50 years of age, exposure to > 10,000 radiation hours was significantly associated with a lower likelihood of AA, after adjusting for age, sex, diabetes mellitus, hypertension, and obstructive sleep apnea (adjusted OR 0.57; 95% CI 0.38-0.85, p = 0.007). The traditional risk factors for AA (age, sex, hypertension, diabetes mellitus, and obstructive sleep apnea) correlated positively with AA in our data set. Cataracts, a well-established complication of radiation exposure, were more prevalent in those exposed to > 10,000 h of radiation vs. those exposed to ≤10,000 h of radiation, validating the dependent (AA) and independent variables (radiation exposure), respectively.

Conclusion

AA prevalence may be inversely associated with radiation exposure in Cardiologists based on self-reported data on diagnosis and radiation hours. Large-scale prospective studies are needed to validate these findings.

No changes in myocardial perfusion following radiation therapy of left-sided breast cancer: A positron emission tomography study

BACKGROUND

Adjuvant radiation therapy (RT) for breast cancer has improved overall survival. However, incidental exposure of the heart has been linked to development of radiation-induced heart disease. The aim of this study was, in a cohort of asymptomatic post-irradiation breast cancer patients, to investigate changes in myocardial blood flow (MBF) and presence of perfusion defects in myocardial perfusion positron-emission-tomography (PET) in the irradiated myocardium.

METHODS AND RESULTS

Twenty patients treated with RT for left-sided breast cancer underwent 13N-ammonia myocardial perfusion PET 7(± 2) years after breath adapted RT to a total dose of 48 Gy given in 24 fractions. No differences in rest or stress MBF were noted between the irradiated and non-irradiated myocardium (1.29 (± 0.29) vs 1.33 (± 0.29) mL/g/min, ns; 2.74 (± 0.59) vs 2.78 (± 0.66) mL/g/min, ns, respectively). One patient demonstrated a myocardial perfusion defect localized in the irradiated anterior wall myocardium.

CONCLUSION

Although limited by a small sample size, early signs of cardiac injury detected by NH3 myocardial perfusion PET was at least not frequent in our cohort of patients treated with a modern RT technique for left-sided breast cancer, even 7 years after treatment. The findings however, may not rule out subsequent development of myocardial injury.

Radiation-Induced Cardiovascular Disease

PURPOSE OF REVIEW

Thoracic radiation therapy is an effective treatment for several malignancies, such as Hodgkin's lymphoma and breast cancer. Over the years, however, the incidence of cardiovascular events has increased in these patients, notably in younger survivors who do not have traditional risk factors. This review summarizes the pathology, incidence, clinical presentation, and management of cardiac events after radiation therapy.

RECENT FINDINGS

Mediastinal radiation therapy accelerates the atherosclerosis process, resulting in early onset coronary artery disease. Valvular disease due to radiation therapy typically affects the left-sided valves, with aortic regurgitation being the most common. Rarely, it may lead to aortic stenosis requiring surgical interventions. Pericardial involvement includes acute and chronic pericardial disease and pericardial effusion. New studies are investigating the prevalence and pathogenesis of autonomic dysfunction in cancer survivors who have undergone mediastinal and neck radiation. Radiation therapy itself causes vascular endothelial dysfunction, resulting in clinical cardiovascular events, manifesting many years after completion of therapy. There remains little guidance regarding screening and therapies to prevent cardiovascular events in this population.