Researchers Urge Restraint in Treating Children with Thyroid Cancer

The nuclear crisis that resulted from the March 11 earthquake and tsunami in Japan focused the world’s attention on radiation exposure, a proven risk factor for thyroid cancer, particularly in children.

Although pediatric thyroid cancer continues to be effectively treated with thyroidectomy with or without lymph node dissection, and in some cases, radioactive iodine (RAI), new analysis suggests RAI may not be necessary for all patients with thyroid cancer.

Gary Francis, MD, PhD, of Virginia Commonwealth University Children’s Medical Center in Richmond and Steven Waguespack, MD, of M.D. Anderson Cancer Center in Houston say exposing children to RAI for treatment of differentiated thyroid cancer may contribute to an increase in second cancers.

“Radioactive iodine should generally be prescribed for those at very high risk for recurrence or known to have microscopic residual disease and those with iodine-avid distant metastases,” the researchers wrote in The Journal of the National Comprehensive Cancer Network. However, “RAI should be considered in other patients only after carefully weighing the relative risks and benefits and the aggressiveness of the clinical presentation, because RAI may be associated with an increased risk for second malignancies and an increase in overall morbidity and mortality.”

Differentiated thyroid cancer—rare in children and adolescents under age 18—is less lethal than the adult cases of the disease but more likely to recur when diagnosed in childhood.

Thyroid cancer is rarely an immediate danger to a child’s life, according to the researchers, and mortality from thyroid cancer, when it occurs, is not usually seen until decades after diagnosis, underscoring the need to balance treatment aggressiveness during childhood with the known good outcomes in the majority of cases. They recommended that doctors carefully consider the risks and benefits of routine RAI treatment of pediatric thyroid cancer and take an individualistic approach to its use.