Some considerations for future research into the risks of radiation-induced cardiovascular diseases

Excerpt

The radiosensitivity of the heart has been known since Louis Fajardo described severe myocardial fibrosis leading to congestive heart failure in patients who had been cured from Hodgkin’s disease by mantle field radiotherapy [1, 2]. In the classical form of this treatment, considerable parts of the heart are in the primary beam and receive doses over 40 Gy (fractionated). The report by Kodama in the early 1990s of a significant dose-related increase in deaths from heart diseases among Japanese A‑bomb survivors observed in the Life Span Study, which was compatible with a linear non-threshold dose–risk relationship [3], stimulated a large number of epidemiological and clinical research activities, e. g. in patients treated for nonmalignant disorders such as peptic ulcer by Carr et al. [4] or in many other Hodgkin’s disease cohorts [5‐7]. The most important studies addressed the cardiovascular disease risk of patients who had been cured from breast cancer by postoperative radiotherapy [8, 9]. Other radiotherapy studies explored more specific heart diseases, such as myocardial infarction or valvular diseases [10, 11]. An increased mortality from heart diseases was also demonstrated among people who had been occupationally exposed to ionizing radiation [12, 13]. The results of these studies were reviewed again and again, by individual scientists or committees, e. g. [14, 15], thus confirming the extraordinary radiosensitivity of the heart. Most studies had very poor dosimetry, none had individual dosimetry and nearly all relied on mean heart dose estimates. Only few studies attempted to determine partial heart doses in relation to specific radiation-induced heart diseases [16‐19]. …