Risk of radiation-induced malignancies from CT scanning in children who underwent shunt treatment before 6 years of age: a retrospective cohort study with a minimum 10-year follow-up

Abstract

<jats:sec> <jats:title>Object</jats:title> <jats:p>A number of mathematical models predict the risk of future cancer from the ionizing radiation exposure of CT scanning. The predictions are alarming. Some models predict 29,000 future cancers and 14,500 deaths in the US will be directly caused by 1 year's worth of CT scanning. However, there are very few clinical data to justify or refute these claims. Young children are theoretically highly susceptible to the damaging effects of radiation. In this study, the authors examined children who underwent CSF shunt placement before 6 years of age. The authors chose to study shunt-treated patients with the assumption that these patients would undergo future imaging, facilitating surveillance. They chose a study period of 1991–2001 to allow more than 10 years of follow-up data.</jats:p></jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>The authors studied 104 consecutive children who underwent CSF shunt placement prior to 6 years of age and who had at least 10 years of follow-up data. Sixty-two of these patients underwent shunt placement prior to 1 year of age. The age at the initial scanning session, the number of future CT scanning sessions, diagnosis, and results of any future studies were recorded. The age-specific radiation dose was calculated for children younger than 1 year. Children younger than 1 year at the time of shunt placement were evaluated separately, based on the assumption that they represented the highest risk cohort. The authors examined all data for any evidence of future leukemia or head/neck tumor (benign or malignant).</jats:p></jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>These children underwent a total of 1584 CT scanning sessions over a follow-up period of 1622 person-years. A total of 517 scanning sessions were performed prior to 6 years of age, including 260 in the 1st year of life. Children who underwent shunt placement before 1 year of age underwent an average of 16.3 ± 13.5 CT sessions (range 1–41). Children undergoing placement between 1 and 6 years of age received an average of 14.1 ± 12.5 CT studies (range 5–52). There were no subsequent tumors (benign or malignant) or leukemia detected.</jats:p></jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>Previously published models predict a significant number of future cancers directly caused by CT scanning. However, there are very few published clinical data. In the authors' study, zero future radiation-induced malignancies were detected after routine CT scanning in a high-risk group. While the authors do not consider their single-institution study adequate to define the actual risk, their data suggest that the overall risk is low. The authors hope this study encourages future collaborative efforts to define the actual risk to patients.</jats:p></jats:sec>

CT scan exposure in children with ventriculo-peritoneal shunts: single centre experience and review of the literature

“…[9] Interestingly, White et al also report high numbers of CT scans in children, with even higher rates in neonates and infants undergoing shunt insertion before the age of 1 year, compared with those whose shunt was inserted between 1 and 6 years of age. [37] This trend is reflected in our own data and is most probably due to a previously identified correlation between younger age at the time of shunt insertion and increased rates of malfunction and infection. [1,10] Of the children undergoing 'in house' CT head scans in our study, surgical intervention was observed following 31% of scans.…”

“…However, White et al performed a retrospective cohort study, including 104 children who underwent CSF shunt placement. In total, 1,584 CT head scans were performed over a 10year period, with no observed malignancies within the cohort [37]. Despite these findings appearing reassuring, there is strong epidemiological evidence linking CT scanning in childhood with an increased risk of malignancy.…”

Postoperative imaging for detection of recurrent arteriovenous malformations in children

“…22 White et al demonstrated that in children undergoing surveillance for shunt malfunction, the mean brain dose from a mean of 16.3 CT scans in the first year of life was 321 mGy, with no increase in the risk of malignancy over the 10-21 years of follow-up. 30 Consistent with this conclusion, the largest study of population-based risk of malignancy after radiation exposure by dose demonstrated no significant increase in the relative risk of malignancy after exposure to 0.01-9.99 Gy. 27 Additionally, neurological and nonneurological risks of DSA in the infant population were recently reviewed at our institution with no increase in morbidity in this population.…”

“…The appropriate follow-up modality and timing are therefore subjects of debate, particularly in light of concerns regarding radiation exposure and general anesthesia in children. 7,22,30 We present our experience with surveillance for AVM recurrence, associated risk factors, and clinical outcome, while considering the implications of these findings for follow-up protocols after treatment.…”

Trends in the utilization of computed tomography and cardiac catheterization among children with congenital heart disease

“…One previous study (2009) claimed that approximately 29,000 future cancers could be related to 1 year of CT scan in the United States. 48 However, a recent study 49 published in 2014 claimed that zero radiationinduced malignancy were detected after routine CT scans. They evaluated 104 children who underwent cerebrospinal fluid shunt placement prior to the age of 6 years and with at least 10 years of follow-up data.…”