Abstract
CONTEXT: The incidence of thyroid cancer in young people has increased over the past 40 years. While prognosis is favorable, recurrence rates may reach 20%. We previously reported the pathological characteristics of 220 young patients with thyroid cancer; here, we evaluated their long-term outcomes and recurrence risk. OBJECTIVE: To identify predictors of recurrence in pediatric and adolescent thyroid cancer. DESIGN SETTING AND PATIENTS: A prospective cohort of 213 patients aged 5-19 years who underwent initial surgery at Fukushima Medical University Hospital between 2012 and 2020. MAIN OUTCOME MEASURES: Recurrence was defined as cytological evidence of cancer in the thyroid remnant or lymph nodes after initial surgery or the appearance of new tumor lesions on imaging of other organs after surgery. RESULTS: Seventeen of 213 patients (8.0%) experienced recurrence during a median follow-up of 8 years. In the overall cohort, younger age was the strongest predictor of recurrence, particularly in patients younger than 15 years. Other pathological features such as lymph node metastasis and pathological intra-thyroidal dissemination (ITD) showed associations in univariate analysis but lost significance after adjustment for age. CONCLUSION: Unilateral lobectomy was not associated with an increased risk of recurrence. Recurrence was most frequent in patients <15 years and occurred more often in those with multifocal disease, advanced stage, N1b nodes, or ITD. These findings provide clinically relevant prognostic insights that may help refine clinical management in young patients with thyroid cancer.