Submandibular gland preservation versus removal during neck dissection in oral squamous cell carcinoma: a systematic review and meta-analysis.

INTRODUCTION

Submandibular gland (SMG) resection is traditionally included in level IB neck dissection for oral squamous cell carcinoma (OSCC), although isolated SMG metastases are rare. Routine removal may contribute to xerostomia and a reduced quality of life. This systematic review and meta-analysis assessed whether SMG preservation compromises oncologic outcomes or improves functional outcomes.

METHODS

This systematic review and meta-analysis followed PRISMA 2020 and Cochrane guidelines, with prospective registration in PROSPERO (CRD420251027851). The literature search included PubMed, Scopus, and the Cochrane Library up to March 2025. Eligible studies compared oncologic or functional outcomes after SMG preservation versus resection in OSCC. Risk of bias was evaluated using the ROBINS-I tool, and evidence certainty was assessed with the Grading of Recommendations Assessment, Development and Evaluation approach.

RESULTS

Eight studies comprising 1,220 patients met the inclusion criteria. Preservation of the SMG did not increase locoregional recurrence (RR 1.05, p = 0.81), affect disease-specific survival (RR 0.86, p = 0.69), or alter overall survival (RR 0.80, p = 0.57) compared with gland resection. Oncologic safety was maintained in early-stage OSCC (T1-T2 N0). Xerostomia outcomes were variably reported across four studies; while some studies suggested a possible trend toward reduced postoperative dry mouth with SMG preservation, findings were inconsistent due to differences in xerostomia assessment methods and patient cohorts.

CONCLUSION

Based on low-certainty evidence, SMG preservation during neck dissection appears not to compromise oncologic outcomes in selected cases. However, the impact on xerostomia remains inconclusive given the heterogeneity among studies.

SYSTEMATIC REVIEW REGISTRATION: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD420251027851, identifier CRD420251027851.