Loading...
Computed tomography angiography (CTA) is fast becoming a common diagnostic test for coronary artery disease, yet data are scarce regarding its potential cancer risk. Therefore, investigators utilized Monte Carlo simulation and a model based on the National Academies’ BEIR VII Phase 2 Report to determine the lifetime attributable risk (LAR) for cancer incidence associated with radiation exposure from a 64-slice CTA study and the extent to which patient age or sex or the scan protocol modified this risk.
According to the researchers’ calculations, the estimated risk for cancer from a standard cardiac scan, without tube correction modulation (TCM), ranged from a high of 1 in 143 for a 20-year-old woman to a low of 1 in 3261 for an 80-year-old man. Irrespective of sex, risk decreased with increased age at the time of study. However, irrespective of age, women had a higher LAR for cancer than men. This difference was driven primarily by women’s greater radiosensitivity and breast-cancer risk. When TCM protocols were used, cancer risk was reduced by 35%. Cancer risk was highest when combined heart and aorta studies were performed.
Einstein AJ et al. Estimating risk of cancer associated with radiation exposure from 64-slice computed tomography coronary angiography. JAMA 2007 Jul 18; 298:317-23.
Comment
This simulation study suggests that the lifetime risk for cancer associated with radiation exposure during 64-slice CTA is especially high in women and in younger patients, especially in those undergoing combined cardiac and aortic scans. These findings and the availability of alternative diagnostic tests should factor into clinical decision making, particularly regarding women, in view of current recommendations regarding this technology.