The number of CT scans corresponds to an increase in risk of hematologic malignant neoplasms, especially in children under age 16.
Getting an abdominal CT scan for suspected acute appendicitis can increase the risk of developing a blood cancer, particularly in children under age 16, a new study has found.
The debate about whether exposure to CT radiation can actually augment the likelihood of cancer has been long-standing. In a study published on Jan. 20 in JAMA Surgery, investigators from South Korea examined a large study population, determined the risk exists, and pushed for radiologists to continue to be judicious in their use of radiation with children.
“The incidence of hematologic malignant neoplasms tended to increase with the number of abdominopelvic CT examinations,” said the team led by Ji Hoon Park, M.D., Ph.D., from the radiology department at Seoul National University Bundang Hospital. “The carcinogenic risk from abdominopelvic CT radiation was most pronounced in patients aged 0 to 15 years.”
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Appendicitis is a common problem among younger patients, and figuring out whether CT exposure actually raises their cancer risk is critical, the team explained. Not only are children more vulnerable to the effects of radiation, but CT is being used more and more often with this particular condition. This could be problematic, they pointed out, because roughly 10 percent of the body’s highly radiosensitive red bone marrow is contained in areas imaged by abdominopelvic CT.
To determine the impact of these diagnostic scans, the team examined records from the National Health Insurance Service for 825,820 individuals with no underlying cancer risks who also underwent an appendectomy between Jan. 1, 2005, and Dec. 31, 2015. They looked for both the incidence ratio rate (IRR) of hematologic malignant neoplasms within two years of the procedure, as well as organ cancers and overall cancers within five years.
They divided their study population into two groups: 306,727 patients who underwent a CT scan, averaging 14.7 mGy, either 7 days prior or 7 days after their appendectomy and 519,093 who did not have a CT scan. Based on their analysis, they identified cancer in 323 individuals in the CT-exposed group and 500 patients who did not undergo a CT scan, resulting in a hematologic malignant neoplasm IRR of 1.26.
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According to their evaluations, the uptick in neoplasms began at roughly three years post-CT exposure. While the absolute excess IRR for all neoplasms reached 4.44, the CT group, specifically, experienced a 1.40 IRR for leukemia. The risk of developing a hematologic neoplasm was highest among patients younger than age 16, they said. The rise in risk also corresponded to the number of CT scans – 1.21 IRR with one CT; 1.60 IRR for patients who had two or more.
In an accompanying invited commentary, a group of experts, led by Paulina Salminen, M.D., Ph.D., from the division of digestive surgery and urology at Turku University Hospital in Finland, stressed the need to optimize the use of CT for appendicitis in children. The modality is the gold standard with adults, they said, consequently, providers just be as gentle as possible and implement low-dose CT with children.
Park’s team agreed, noting that the results of their study point to a need for adjusting the use of CT for the younger population.
“From our results, we are not claiming that use of periappendectomy CT should be discouraged in all patients. Historically, the increase in the use of CT coincided with the reduction of negative appendectomy rates,” they said. “At least in children, the importance of judicious use of CT cannot be overstated, as suggested by the high IRR for hematologic malignant neoplasms in children younger than 16 years.”
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