Neoadjuvant therapy with anlotinib in a 5-year-old child with advanced papillary thyroid carcinoma: a case report.

Background: Pediatric papillary thyroid carcinoma (PTC) is frequently diagnosed at a locally advanced stage. Although anlotinib, an oral multi-target tyrosine kinase inhibitor (mTKI), has been employed in the treatment of locally advanced thyroid cancer (LATC) in adults, experience regarding its use in children remains limited. Case presentation: A 5-year-old boy was diagnosed with LATC, characterized by extensive lymph node metastases, encasement of multiple cervical vascular structures, and distant pulmonary metastases, rendering the tumor unresectable. In accordance with a multidisciplinary team (MDT) recommendation and existing pediatric evidence, neoadjuvant therapy with oral anlotinib (8 mg/day, administered on a 2 weeks on/1 week off schedule per cycle) was initiated. No severe adverse drug reactions were observed during treatment. Following 3 cycles of neoadjuvant therapy, the tumor demonstrated sufficient regression to achieve resectability, and the patient subsequently underwent successful staged surgical resection. Permanent hypoparathyroidism was the only complication. Methods: The patient's medical and imaging records were retrospectively analyzed. Tumor response was assessed using standardized Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1, and adverse events related to targeted therapy were graded according to the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. Conclusion: This report describes a pediatric case of LATC treated with anlotinib-based neoadjuvant therapy, which may serve as a reference for future neoadjuvant treatment approaches in children with LATC.