Radiation-induced coronary artery calcification in breast cancer: insights from a systematic review and meta-analysis

Radiation therapy for breast cancer increases the risk of coronary artery disease by promoting atherosclerotic plaques. However, the extent of changes in coronary artery calcification (CAC) scores postradiation and the influencing factors remain unclear. This systematic review and meta-analysis evaluated studies investigating changes in CAC scores following breast cancer radiation therapy. Data abstraction was independently performed by two unblinded reviewers using structured collection forms, with no divergences in data collection. The nine-star Newcastle-Ottawa Scale scoring system assessed methodological quality. Statistical analysis was conducted using Comprehensive Meta-Analysis software. Among eight studies (1972 patients), radiation doses ranged from 47 to 60 Grays. The overall rate of CAC score increase or new appearance postradiation was 25.8% [95% confidence interval (CI), 21.3-30.8%]. The rate was significantly higher after left-sided radiation at 32.3% (95% CI, 25.7-39.6%) compared to 16.1% (95% CI, 5.8-37.3%) for right-sided radiation. CAC score development occurs in approximately one-quarter of breast cancer patients after radiation therapy, with a significantly higher risk following left-sided radiation. These findings underscore the need for tailored monitoring strategies to mitigate cardiovascular risks in this population.