The benefit of neck computed tomography compared with its harm (risk of cancer)

The purpose of this study was to compare the benefit of neck computed tomography (CT) of identifying important cervical spine injuries (CSIs) with its harm of radiation exposure and cancer risk.

A PubMed search for published studies relating to CSI in trauma, cervical spine imaging, CT, and cancer risk was conducted. Article abstracts were reviewed, and selected published studies relating to the study objective were retrieved.

Of 100,000 trauma patients, neck CT scans were obtained in 3,767 to 26,785 patients. Of 100,000 patients with trauma on whom a neck CT scan was performed, a CSI was identified in 2,470 to 33,898 patients. Clinically important CSI ranged from 4,724 to 27,119 per 100,000 CT scans. For every 100,000 neck CT scans performed, additional cancer cases occur in a low end estimate of a thyroid cancer cases to a high end estimate of 100 male and 700 female cancer cases. In females, cancer risks are higher than in males, and these are closer to, but still less than, the incidence of clinically important CSI found by CT.

CT's benefit of identifying important CSIs in the published studies exceeds its cancer harm risk. However, at their extremes, the numbers are disturbingly close. Limiting neck CT scanning to a higher-risk group would increase the gap between benefit and harm, whereas performing CT routinely on low-risk cases approaches a point where its harm equals or exceeds its benefit.

Systematic review, level IV.