Cervical Lymph Node Invasion in Pediatric Salivary Gland Malignancies: Clinical Overview and Therapeutic Implications

Abstract

Background and aims: Pediatric salivary gland malignancies (SGM) present challenges in managing cervical nodes. We aimed to characterize lymph node invasion to inform decisions regarding the need of systematic wide lymph node dissection (WLND).

Methods: International retrospective study, conducted across seven large French and American pediatric centers, including pediatric patients (0-18 years) diagnosed with SGM from 2000 to 2020.

Results: Among the 82 patients (median age 13 years), the parotid gland was frequently affected (60 cases). Histotypes comprised mucoepidermoid (mucoepidermoid carcinoma [MEC], 43 cases), acinic cells (acinic cells carcinoma [AcCC], 22 cases), adenoid cystic (adenoid cystic carcinoma [AdCC], 8 cases), (MASC, 6 cases), and adenocarcinoma (3 cases). Primary treatments were surgery (82 cases) and radiotherapy (20 cases; median dosage 64 gray). Cervical nodes therapy included WLND (≥2 levels, 29 cases), limited nodes resection (LNR; one level, 13 cases), and/or irradiation (4 cases; median 54 gray; range 52.0-63.0). At diagnosis, six patients had cervical node invasion (CNI) managed with LNR (four cases), WLND (two cases), and radiotherapy (three cases). After a median follow-up of 6 years (range 1-22), nine patients had tumor event: local (four cases), cervical relapse/progression (three cases) or combined (two cases). Of the nine with CNI, at diagnosis or relapse, four had MASC. Five-year event-free and overall survival (OS) rates were, respectively, 90.1% and 98.8%.

Conclusions: CNI is rare in pediatric SGM but noted in 11% of cases, with higher incidence in MASC. Overall, outcome in SGM is good with a tailored locoregional multidisciplinary approach. Systematic lymph node dissection should be reconsidered.

Summary: This international multi-institutional study analyzed the clinical presentation and the cervical pattern of relapse of 82 pediatric patients with newly diagnosed salivary gland malignancies. Overall, nodal invasion was rare at diagnosis and only noted in 7%. In addition, 6% developed nodal relapse during follow-up. Incidence of nodal spread was frequent in mammary analogue secretory carcinoma (MASC). The overall outcome was promising with a tailored locoregional multidisciplinary approach. Systematic lymph node dissection should be reconsidered in pediatric salivary gland tumors.

Keywords: Salivary gland carcinoma; children; lymph node metastases; lymph nodes dissection; radiotherapy; surgery.