Radiation-associated cardiovascular dysfunction is an umbrella term which encompasses a broad range of both acute and late manifestations. These can include myocardial damage, valvular heart disease, vasculopathy including coronary artery disease, pericardial conditions and conduction system abnormalities. Importantly, these conditions may arise either acutely, or more commonly- with quite protracted latency periods (years to decades) after radiation exposure. Pathophysiological mechanisms of action leading to these conditions will be described.
Clinical symptoms may be difficult to discern as often times are non-specific and overlapping with other cardiorespiratory illness, and it is here that relevant cardiovascular imaging can play an important role. Another challenge is discriminating the relative contributions of radiation, systemic therapy and patient’s cardiovascular risk factors, the so called “multiple-hit hypothesis”.
There has been substantive progress in determining more detailed radiation dosimetry and treatment volumes and correlation with cardiac substructures to allow for development of risk prediction tools incorporating treatment and patient variables with greater accuracy, leading to larger clinical cohort data replete with longer term follow-up outcomes. Furthermore, advancement in targeted modern radiotherapy techniques including deep-inspiration breath hold, together with the application of specified dose-volume thresholds, have sought to limit radiation dose to cardiac substructures.
Clinical approaches including comprehensive cardio-oncology assessment, tailored management and follow-up, education and awareness will help to mitigate the risk of cancer survivors’ longer term cardiovascular sequelae.