The relationship between radiation doses to coronary arteries and location of coronary stenosis requiring intervention in breast cancer survivors

Abstract

Background To assess the relationship between radiation doses to the coronary arteries (CAs) and location of a coronary stenosis that required intervention after three-dimensional conformal radiotherapy (3DCRT) for breast cancer (BC). Methods The study population consisted of 182 women treated for BC in Sweden between 1992 and 2012. All women received 3DCRT and subsequently underwent coronary angiography due to a suspected coronary event. CA segments were delineated in the patient’s original planning-CT and radiation doses were recalculated based on the dose distribution of the original radiotherapy (RT) plan. The location of the CA stenosis that required intervention was identified from the Swedish Coronary Angiography and Angioplasty Registry (SCAAR). Logistic regression analysis was used to assess the relationship between CA radiation doses and risk of a later coronary intervention at this specific location. Results The odds ratio (OR) varied by radiation dose to the mid left anterior descending artery (LAD) ( p = 0.005). Women receiving mean doses of 1–5 Gray (Gy) to the mid LAD had an adjusted OR of 0.90 (95% CI 0.47–1.74) for a later coronary intervention compared to women receiving mean doses of 0–1 Gy to the mid LAD. In women receiving mean doses of 5–20 Gy to the mid LAD, an adjusted OR of 1.24 (95% CI 0.52–2.95) was observed, which increased to an OR of 5.23 (95% CI 2.01–13.6) for mean doses over 20 Gy, when compared to women receiving mean doses of 0–1 Gy to the mid LAD. Conclusions In women receiving conventional 3DCRT for BC between 1992 and 2012, radiation doses to the LAD remained high and were associated with an increased requirement of coronary intervention in mid LAD. The results support that the LAD radiation dose should be considered in RT treatment planning and that the dose should be kept as low as possible. Minimising the dose to LAD is expected to diminish the risk of later radiation-induced stenosis. Electronic supplementary material The online version of this article (10.1186/s13014-019-1242-z) contains supplementary material, which is available to authorized users.

Long-term risk of ischemic heart disease after adjuvant radiotherapy in breast cancer: results from a large population-based cohort

“…In a recent systematic review of trials from 2010 to 2015, mean heart doses were 5.2 Gy and 3.7 Gy in left-sided and right-sided RT, respectively [11]. We recently showed considerably lower doses in a dosimetry study of 182 BC patients selected from the same registry as the present study, although including only patients undergoing coronary angiography due to a cardiac event [27]. The median mean heart dose was 0.6 Gy (interquartile range (IQR) 0.4-1.0) after right-sided RT and 2.7 Gy (IQR 1.7-4.2) after left-sided RT.…”

“…The median mean heart dose was 0.6 Gy (interquartile range (IQR) 0.4-1.0) after right-sided RT and 2.7 Gy (IQR 1.7-4.2) after left-sided RT. Moreover, the left/right RT dose difference was higher in the mid and distal LAD, where median mean doses were 3.6 Gy (IQR 2.4-6.2) and 26.7 Gy (IQR 7.0-41.0) after left-sided RT, and 0.5 Gy (IQR 0.1-0.8) and 0.3 Gy (IQR 0.1-0.8) after right-sided RT, respectively [27].…”

Radiation effect on late cardiopulmonary toxicity: An analysis comparing supine DIBH versus prone techniques for breast treatment

“…While MHD certainly is a surrogate for overall cardiac dose, especially in an older era before more conformal treatments, it does not always adequately represent dose to individual cardiac substructures and their consequent late effects. Nilsson et al demonstrated how the location of radiation hot spots in the coronary arteries, and in more modern series, specific doses to the LAD, correlate with degree of stenosis and the requirement of coronary intervention of these specific areas . Other reports have established that various cardiac substructures such as left ventricle, cardiac valves, and left circumflex artery are predictors of cardiotoxicity .…”

Relationship between Changes in Myocardial F-18 Fluorodeoxyglucose Uptake and Radiation Dose after Adjuvant Three-Dimensional Conformal Radiotherapy in Patients with Breast Cancer

“…In a previous dosimetry study, patients with left breast cancer had absorbed a dose of 2.3 ± 0.7 Gy to the heart and the left anterior descending coronary artery showed the highest radiation dose (7.6 ± 4.5 Gy) among the coronary arteries, while all patients with right breast cancer had absorbed a dose lower than 2.0 Gy [5]. These results emphasize the need to develop advanced RT techniques that can reduce the radiation dose to the heart and to screen patients with left breast cancer for radiation-induced heart disease [4,9,10].…”

“…Adjuvant RT reduces the risk of mortality by 16% and that of local recurrence by more than 50% in patients with breast cancer [1,3]. However, for patients with left breast cancer, some territory of the heart is often included in the RT field, which could result in radiation-induced damage to the myocardium and coronary artery [4,5], and previous clinical studies have reported increased risk of ischemic heart disease, myocardial infarction, and cardiac disease-related mortality in patients with left breast cancer compared to those with right breast cancer [6][7][8]. In a previous dosimetry study, patients with left breast cancer had absorbed a dose of 2.3 ± 0.7 Gy to the heart and the left anterior descending coronary artery showed the highest radiation dose (7.6 ± 4.5 Gy) among the coronary arteries, while all patients with right breast cancer had absorbed a dose lower than 2.0 Gy [5].…”