Thyroid tumor surveillance using ultrasound in childhood cancer survivors.

Background The optimal method for thyroid cancer screening in childhood cancer survivors (CCSs) who received radiation involving the thyroid gland is still debated. We describe a case series of ultrasound surveillance for thyroid tumor in CCSs in our institute. Methods We conducted thyroid tumor surveillance for CCSs with a history of radiation therapy involving the thyroid. The basic screening method was palpation. Thyroid ultrasound was also performed for patients who agreed after its benefits and risks were explained to them. We surveyed CCSs who visited the long-term follow-up outpatient clinic in our institution between October 2014 and September 2018. Results Of 82 CCSs who visited our institution during the study period, 44 were eligible for inclusion. None had a mass identified by palpation. Thyroid ultrasound was performed in 39 CCSs, and we identified thyroid nodules in 27. Four patients had a nodule with malignant echo features. Two of these cases received biopsies, and one patient was ultimately diagnosed with an early stage thyroid carcinoma. Conclusions Childhood cancer survivors irradiated in the thyroid had a higher prevalence of thyroid nodules than the general population. Ultrasound screening contributed to early detection of impalpable thyroid cancer and enabled us to perform minimal surgery. Thus, ultrasound appears to be a useful option for secondary thyroid cancer screening. The thyroid tumor surveillance modality should be considered according to the individual case, and the patient must receive a clear explanation of the benefits and risks. These results could help doctors consider how to screen for secondary thyroid cancer.