ARRS: Disease risk outweighs risk of CT-induced cancer in young adults

CT-induced cancer is always a concern when imaging younger patients, but an analysis of radiation risks has shown that young patients who undergo chest or abdominopelvic CT are more than 35 times more likely to die of their disease than develop a radiation-induced cancer, according to a study presented May 1 at the annual meeting of the American Roentgen Ray Society in Vancouver.

Rob Zondervan, MA, and colleagues from Massachusetts General Hospital in Boston conducted the analysis of all patients aged 18 to 35 who underwent chest or abdominopelvic CT at three Boston-area hospitals from 2003 to 2007. A total of 23,359 patients were included, some of whom were scanned more than 15 times.

The researchers found that in the chest CT group, 575 out of 8,133 patients were deceased after a mean follow-up of approximately four years. For comparison, that same group would be expected to develop 12 cases of radiation-induced cancer based on the BEIR-VII method of determining CT-induced cancer incidence, according to the authors.

In the abdominopelvic CT group, 1,124 out of 15,226 patients were deceased after a mean follow-up of approximately 3.5 years, compared with 23 cases of predicted cancer incidence.

“Our results indicate that the risk from underlying disease overshadows risk from CT radiation-induced malignancy, even in young adults," Zondervan said in a statement.

The data were broken down based on the frequency of CT exams; across all scanning frequencies the risk of short-term mortality from inherent disease was larger than the BEIR-VII-predicted rick of cancer incidence. In this study, the majority of cancers were predicted in patients who were very rarely scanned (one or two scans), but the authors noted this is because the “very rarely scanned” group was much larger than the other scan frequency groups.

"These results do emphasize that we need to focus our radiation reduction efforts on patients who are very rarely scanned as well as those who are more frequently scanned," said Zondervan.