# Dose-related association between radiation exposure from computed tomography (CT) scans during trauma hospitalizations and subsequent risk of developing new-onset cancers

## TL;DR

This study finds that higher radiation doses from CT scans during trauma hospitalizations are linked to increased cancer risk and mortality later in life.

## Contribution

The study demonstrates a dose-dependent association between CT radiation exposure and subsequent cancer risk in trauma patients.

## Key findings

- Radiation exposure from CT scans is significantly associated with increased risk of new-onset cancer.
- Higher radiation doses are correlated with increased cancer-related mortality.
- Findings are consistent across a larger cohort after accounting for missing data.

## Abstract

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.

Medical imaging, especially CT (Computed Tomography) scans, uses X-rays and computer technology to create detailed pictures of the inside of the body. These scans are commonly used after serious injuries to help doctors assess damage to bones, blood vessels, and soft tissues. However, the long-term health risks from the radiation used in these scans—particularly the risk of developing cancer—are not well understood. In our study, we looked at long-term health data from 2662 adult trauma patients in Western Australia over a 16-year period. We found that patients who received higher doses of radiation from CT scans during their hospital stay were more likely to develop cancer and die from it later on. The most common cancer-related deaths were from lung cancer (19%), brain cancer (glioblastoma multiforme, 14%), and pancreatic cancer (14%). These findings highlight the importance of avoiding unnecessary radiation exposure, especially in younger patients who may be more vulnerable to long-term effects.

Yaw et al. assess the association between cumulative radiation exposure from CT imaging during trauma hospitalization and subsequent risk of developing malignant neoplasms and cancer-related mortality. Related radiation exposure is associated with a dose-dependent increase in the risk of subsequent cancer incidence and mortality.