TBI for pediatric malignancies linked to multi-organ dysfunction
Patients aged younger than 3 years who underwent total body irradiation after hematopoietic stem cell transplant were at risk for multi-organ dysfunction, including endocrine, metabolic, renal, eye and neurocognitive abnormalities, study results showed.
Total body irradiation (TBI) is a vital preparative component of hematopoietic stem cell transplant (HSCT) for patients with pediatric malignancies, specifically lymphoblastic leukemia.
“These kids basically lie on a table and truly do get radiation from head to toe,” Jean Mulcahy-Levy, MD, research fellow at the University of Colorado Cancer Center, said in a press release. “There is a little blocking of the lungs, but nothing of, for example, the brain or the kidneys.”
A patient’s age may influence the risk of late toxicity, with children under 3 years of age potentially at higher risk, Mulcahy-Levy and colleagues wrote. Despite this, few studies have examined the late effects of TBI on infants, the researchers said.
To assess the late effects of children who underwent HSCT with a TBI-based preparative regimen, Mulcahy-Levy and colleagues retrospectively reviewed outcomes of patients treated from 1994 to 2010 at Children’s Hospital Colorado and the University of Colorado Denver.
The researchers identified 81 patients who underwent HSCT. Nineteen received TBI. Of them, 15 were available for follow-up.
The majority (66.7%) had been diagnosed with acute lymphoblastic leukemia. Ten of the patients were female. The mean age at the time of transplantation was 1.4 years, and the mean time to final follow-up after transplantation was 7.4 years.
Study results showed 91.7% of patients experienced growth hormone deficiency, and 71% fell under the 2.5th percentile on their individual growth curve.
Other late effects of radiation observed in more than half of the patients included elevated blood urea nitrogen (78.6%), cataracts (69.2%) and dyslipidemia (69.2%).
Five patients developed hypothyroidism, three developed hypertension and two developed cardiac abnormalities, study results showed.
“It’s not so much that you want to stop TBI, which is frequently a necessary part of treatment,” Mulcahy-Levy said. “But this study shows it’s important to know about these problems in order to address them appropriately and proactively.”
The researchers acknowledged their report is limited given the retrospective nature of the review.
“It is possible that as our follow-up interval increases, the incidence of the various late effects may increase,” Levy and colleagues wrote. “We were unable to compare our cohort to patients who did not receive TBI … However, our results suggest that a longitudinal study with standardized testing for medical and neurocognitive outcomes comparing patients with and without TBI would be beneficial.”
Disclosure: The researchers report no relevant financial disclosures.