Radiation-Induced Coronary Artery Disease and Its Treatment: A Quick Review of Current Evidence

Radiation-induced coronary artery disease during immune checkpoint inhibitor therapy: a case report

Radiation-induced coronary artery disease (RICAD) poses a serious concern for cancer patients post radiotherapy, typically emerging after over a decade. Immune checkpoint inhibitors (ICIs), known for cardiotoxicity, are increasingly recognized for causing cardiovascular complications. Here we report the case of a 63-year-old man with metastatic lung cancer who developed coronary artery disease during his third-line therapy with an ICI (nivolumab) and an antiangiogenic agent (bevacizumab), 3 years post chest radiotherapy. Angiography revealed relatively isolated stenosis in the left main coronary artery ostium, consistent with the radiotherapy site, with no other risk factors, suggesting RICAD. The potential for ICIs to accelerate RICAD development should be considered and necessitates careful surveillance in patients receiving both radiotherapy and ICIs.

Screening for Coronary Artery Disease in Cancer Survivors: JACC: CardioOncology State-of-the-Art Review

Coronary artery disease (CAD) is an important contributor to the cardiovascular burden in cancer survivors. This review identifies features that could help guide decisions about the benefit of screening to assess the risk or presence of subclinical CAD. Screening may be appropriate in selected survivors based on risk factors and inflammatory burden. In cancer survivors who have undergone genetic testing, polygenic risk scores and clonal hematopoiesis markers may become useful CAD risk prediction tools in the future. The type of cancer (especially breast, hematological, gastrointestinal, and genitourinary) and the nature of treatment (radiotherapy, platinum agents, fluorouracil, hormonal therapy, tyrosine kinase inhibitors, endothelial growth factor inhibitors, and immune checkpoint inhibitors) are also important in determining risk. Therapeutic implications of positive screening include lifestyle and atherosclerosis interventions, and in specific instances, revascularization may be indicated.

Radiation-induced coronary artery disease: a difficult clinical conundrum

Accelerated coronary artery disease seen following radiation exposure is termed 'radiation-induced coronary artery disease' (RICAD) and results from both the direct and indirect effects of radiation exposure. Long-term data are available from survivors of nuclear explosions and accidents, nuclear workers as well as from radiotherapy patients. The last group is, by far, the biggest cause of RICAD presentation. The incidence of RICAD continues to increase as cancer survival rates improve and it is now the second most common cause of morbidity and mortality in patients treated with radiotherapy for breast cancer, Hodgkin's lymphoma and other mediastinal malignancies. RICAD will frequently present atypically or even asymptomatically with a latency period of at least 10 years after radiotherapy treatment. An awareness of RICAD, as a long-term complication of radiotherapy, is therefore essential for the cardiologist, oncologist and general medical physician alike. Prior cardiac risk factors, a higher radiation dose and a younger age at exposure seem to increase a patient's risk ratio of developing RICAD. Significant radiation exposure, therefore, requires a low threshold for screening for early diagnosis and timely intervention.

18-Year Follow-Up After Coronary Stenting for Left Main Coronary Artery Lesions

The current treatment of radiation-induced coronary artery disease (RCAD) is comparable to that of generic coronary artery disease (CAD); however, the outcomes of these treatment measures have not been fully examined in RCAD. A 33-year-old woman, without conventional cardiovascular risk factors, presented with left main coronary artery (LMCA) lesions. At the age of 26, she received mediastinal radiation therapy (RT) to treat mixed cellularity Hodgkin lymphoma. One BiodivYsio 3.5 × 18 mm stent was implanted at the LMCA site. At the age of 38, the patient was treated by balloon dilatation because of approximately 50% in-stent stenosis. At the last follow-up in February 2018, when the patient was 51 years old, she no longer complained of chest pain. Coronary angiography showed no de novo or in-stenosis lesions, although optical coherence tomography showed mild neointimal proliferation, calcific plaque, small ruptured intima, and several uncovered struts. The experience of treating this case may shed some light on coronary stenting in coronary lesions caused by RCAD.

Advances in Preclinical Research Models of Radiation-Induced Cardiac Toxicity

Radiation therapy (RT) is an important component of cancer therapy, with >50% of cancer patients receiving RT. As the number of cancer survivors increases, the short- and long-term side effects of cancer therapy are of growing concern. Side effects of RT for thoracic tumors, notably cardiac and pulmonary toxicities, can cause morbidity and mortality in long-term cancer survivors. An understanding of the biological pathways and mechanisms involved in normal tissue toxicity from RT will improve future cancer treatments by reducing the risk of long-term side effects. Many of these mechanistic studies are performed in animal models of radiation exposure. In this area of research, the use of small animal image-guided RT with treatment planning systems that allow more accurate dose determination has the potential to revolutionize knowledge of clinically relevant tumor and normal tissue radiobiology. However, there are still a number of challenges to overcome to optimize such radiation delivery, including dose verification and calibration, determination of doses received by adjacent normal tissues that can affect outcomes, and motion management and identifying variation in doses due to animal heterogeneity. In addition, recent studies have begun to determine how animal strain and sex affect normal tissue radiation injuries. This review article discusses the known and potential benefits and caveats of newer technologies and methods used for small animal radiation delivery, as well as how the choice of animal models, including variables such as species, strain, and age, can alter the severity of cardiac radiation toxicities and impact their clinical relevance.