Dose-related association between radiation exposure from computed tomography (CT) scans during trauma...

The association between radiation dose from Computed Tomography (CT) and subsequent cancer risk in adults remains poorly defined.

We conducted a statewide cohort study to examine the relationship between CT-related radiation exposure - measured by dose-length-product (DLP) - and cancer outcomes among adult trauma patients in Western Australia from 2004 to 2020. Patients with a documented cancer diagnosis within five years prior to trauma were excluded.

After excluding patients with missing smoking data (n = 12,690), 2662 patients (17.3%) are included in the primary analysis. The cohort is predominantly male (75.8%), with a median age of 41 years (IQR: 27-58) and a median Injury Severity Score (ISS) of 17 (IQR: 16-22). Over a median follow-up of 5.9 years (IQR: 4.0-7.9), 374 patients (14.0%) died, including 21 cancer-related deaths (0.8%), accounting for 5.6% of all deaths. During the index trauma admission, patients underwent a median of 6 X-rays (IQR: 3-12) and 3 CT scans (IQR:1-5) with a median DLP of 1,941 mGy*cm (IQR: 637-3,388). DLP and absorbed radiation dose are significantly correlated with injury severity (Pearson r = 0.209 and 0.265, respectively; both p = 0.001). Radiation exposure is significantly associated with increased risk of new-onset cancer (adjusted hazard ratio [aHR]: 1.08 per 1,000 mGy*cm increment in DLP; 95%CI: 1.01-1.16; p = 0.042) and cancer-related mortality (aHR 3.35 for those exposed to >5000 mGy*cm; 95%CI: 1.20-9.38; p = 0.021). These findings are consistent in a larger cohort of 15,352 patients after multiple imputation for missing smoking data.

CT-related radiation exposure during trauma hospitalizations is associated with a dose-dependent increase in the risk of subsequent cancer incidence and mortality.