Benefits of CT for young adults outweigh cancer risks

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The diagnostic benefits of CT for young adults outweigh the cancer-related risks associated with radiation exposure, according to a study published online in Radiology.

Researchers, led by Susanna Lee, chief of women's imaging at Massachusetts General Hospital and an assistant professor of radiology at Harvard Medical School, evaluated the records of 22,000 patients between the ages of 18 and 35 who underwent 16,851 chest CT exams and 24,112 abdominopelvic CT exams between 2003 and 2007.

"The impetus for our study was the concern that the lay press often focuses on potential harm caused to patients by CT imaging," Lee said in an announcement. "Lacking in this discussion is a sense of how sick these patients already are."

The researchers found that the major reasons these young adults underwent chest CT exams was for trauma and cancer, while trauma, abdominal pain and cancer were the main reasons they underwent abdominopelvic CT exams.

Patients were followed for an average of 5.5 years. In that time, 7.1 percent of young adults undergoing chest CT and 3.9 percent undergoing abdominopelvic CT died. Those figures were far greater than the 0.1 percent chance of developing cancer predicted by long-term risk models for each group.

Many of the patients undergoing CT were cancer patients with poor prognoses. However, according to Lee, even by subtracting those patients out, the researchers found that the risk of death in the study group ranged from 2.5 percent to 5 percent, "well above the risk in the general population."

Lee made a point to mention that the exams took place before there was so much focus placed on the cancer risks associated with CT, and that advances in lowering radiation dose probably would make mortality differences even more pronounced today.

"We're not saying be complacent about the radiation risk from CT," Lee said. "But these people being imaged might have been in a motor vehicle accident, or have a perforated appendix or life-threatening cancer, and we're trying to gain information from scans that can help them. That's the part that gets lost in the debate."

To learn more:
- see the abstract in Radiology
- read the announcement

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