Salivary Gland Carcinomas in Children and Adolescents: A Retrospective Analysis of the European Cooperative Study Group for Pediatric Rare Tumours (EXPeRT)

Background Salivary gland carcinomas (SGCs) are exceedingly rare in children, with a reported annual incidence of 0.8-1.4/1,000,000 under 20 years of age. Evidence regarding optimal treatment of pediatric SGCs is limited, and for a long time, no guidelines have been available. Here, we report on an international retrospective series of SGCs in children and adolescents collected by several national rare tumor study groups cooperating in the European Cooperative Study Group of Pediatric Rare Tumors (EXPeRT) Patients and Methods Patients diagnosed between 2000 and 2014 were included Data were reviewed the by the respective national rare tumor working groups and reported on a harmonized data sheet to EXPeRT for central analysis. Results Overall, 121 patients were identified, including 103 patients with parotid tumors, 12 with submandibular tumors and six tumors in minor glands. In 11 patients, SGCs were secondary cancers. Mucoepidermoid carcinoma was the most frequent diagnosis (n=65), followed by acinic cell carcinoma (n=39), adenocystic carcinoma (n=7), sialoblastoma (n=3) and other carcinomas (n=7). All patients underwent tumor resection (R0: 66%, R1: 34%). Neck dissection was performed in 47 patients, revealing nodal metastases in 13. Twenty-four patients underwent irradiation, and 11 patients received adjuvant chemotherapy. During a median follow-up of 25 (6-140 months), 14 relapses were observed (7 local, 5 with nodal and 2 with distant metastases). Five patients died of disease. Higher histological tumor grade was associated with advanced local tumor stage and risk of recurrence. Conclusions SGCs in children and adolescents mostly present as localized tumors with low malignant potential. In approximately 10% of patients, regional lymph node metastases present at diagnosis. After complete resection, prognosis is favorable. Surgery is the mainstay of treatment; adjuvant local or cervical irradiation should be reserved to those rare patients with nodal metastases or less favorable biology such as adenocystic carcinoma.