Prognostic Factors in Squamous Cell Carcinoma of the Maxillary Gingiva and Hard Palate: A Retrospective Analysis From a Single Institution

<i>Background</i>:<i> </i>The maxilla is surrounded by complex anatomical structures, including the nasal cavity, maxillary sinus, zygomatic process, cranial base, mandible, and masticatory muscle space. Therefore, when maxillary squamous cell carcinoma (SCC) is close to or invades these structures, determining clear surgical margins becomes challenging, making complete resection difficult.This study aimed to evaluate factors related to primary recurrence, cervical lymph node recurrence, distant metastasis, and prognosis of primary maxillary SCC at the Department of Oral and Maxillofacial Surgery, Nagasaki University Hospital. <i>Methodology</i>:<i> </i>Patients with SCC of the maxillary gingiva or hard palate treated at a single institute between 2008 and 2022 were reviewed. Age, sex, performance status, primary site, T stage, N stage, pathological N stage, histological differentiation, mode of invasion, lymphatic invasion, vascular invasion, perineural invasion, margin status, extranodal extension, treatment method, and outcome were reviewed. Factors related to survival and local recurrence were analyzed by Cox regression. <i>Results</i>:<i> </i>A total of 61 patients were enrolled. The five-year overall survival (OS) and disease-specific survival (DSS) rates were 74.4% and 83.3%, respectively. Univariate analysis revealed that performance status, T stage, mode of invasion, pathological N stage, lymphatic invasion, vascular invasion, perineural invasion, extranodal extension, and local recurrence were significantly associated with OS and DSS. Local recurrence was observed in 14 of 61 patients (23.0%), all of which had T4 tumors. Finally, 12 patients had uncontrolled primary tumors, while only two had uncontrolled cervical metastases. Margin status did not significantly affect survival and local recurrence. <i>Conclusions</i>: While uncontrolled disease was observed in 14 cT4 cases, no local recurrence occurred in cT1-T3 cases. Histological factors, not margin status, were key prognostic indicators, suggesting the need to re-evaluate treatment strategies for T4 and high-grade tumors.