A Systematic Review of Submandibular Gland Primary Squamous Cell Carcinoma: Clinical Characteristics, Treatment Paradigms, and Survival Outcomes.

Background: This systematic review aims to synthesize evidence on primary squamous cell carcinoma (PSCC) of the submandibular gland (SMG), an exceptionally rare malignancy (<1% of salivary gland tumors, ~2% of submandibular malignancies). Key objectives include characterizing its epidemiology, diagnostic challenges, treatment paradigms, and prognostic outcomes to enhance clinical management.

Methods: Literature search (PubMed, Web of Science, Scopus, Google Scholar) from inception through December 2024 identified English-language studies using MeSH terms ("Carcinoma, Squamous Cell" AND "Submandibular Gland"). After deduplication, 18 full texts were screened; 8 studies (case reports/series, 1992-2023) met the inclusion criteria. Two reviewers independently extracted data on epidemiology, clinical features, management, and outcomes.

Results: PSCC of the SMG demonstrates a strong male predominance (M:F = 3:1) and a mean age of 57.1 years, with prior cervical radiotherapy representing a key risk factor. Clinically, all patients present with submandibular swelling, though only 25% report pain; symptom duration averages 3.9 months, frequently leading to advanced-stage diagnosis. Definitive diagnosis requires rigorous exclusion of metastatic squamous cell carcinoma and histological mimics, necessitating ultrasound-guided fine-needle aspiration cytology and cross-sectional imaging (CT/MRI). Management universally involves SMG resection, with 50% undergoing neck dissection (supraomohyoid or modified radical). Adjuvant therapy was administered to 75% of patients (radiotherapy: 50%; concurrent chemoradiotherapy [CCRT]: 25%). Outcomes reveal a 62.5% survival rate and 37.5% mortality, with 37.5% developing lung metastases. Limited follow-up data highlights both durable remission (no evidence of disease at 2 years) and aggressive progression, including 1 case of early contralateral recurrence 1 month post-CCRT.

Conclusion: PSCC of the SMG is an aggressive malignancy requiring multimodal management. Surgical resection with adjuvant radiotherapy/chemotherapy is common, yet high recurrence rates and metastatic risk persist. Diagnostic rigor remains critical to exclude mimics and metastases. Future studies should establish standardized protocols integrating molecular targeting (eg, EGFR/Wnt pathways).