BackgroundRegional failure (RF) in oral cavity squamous cell carcinoma (OCSCC) is associated with poor outcomes, yet its detailed pattern and its relationship with corresponding neck management strategies remain inadequately defined. This study aims to provide insights for optimizing neck management in OCSCC patients through a comprehensive analysis of RF patterns.MethodsA retrospective review was conducted on patients with OCSCC who underwent radical surgery with or without postoperative radiotherapy (PORT) between 2015 and 2018. Detailed mapping of the initial metastasis and RF patterns was performed and correlated with the corresponding neck management approaches.ResultsA total of 147 patients and 294 necks were included in the analysis. RF was identified as the predominant pattern of failure (5-year rate: 19.8%), with pN+ being the most notable risk factor for regional failure-free survival (RFFS). Compared to the Surgery group, the Surgery+PORT group demonstrated a significantly lower RF rate beyond the dissected region (6.5% vs. 20.0%, p = 0.03) and a numerically lower RF rate beyond the upper neck (5.2% vs. 12.9%, p = 0.10). In dissected necks, RF at level IV accounted for 47.3% of all RF occurrences. The "dissected and irradiated" necks exhibited a lower RF rate than the "dissected-alone" necks (8.7% vs. 13.4%), particularly at level IV (2.2% vs. 8.5%) and Vb (1.1% vs. 3.7%). When compared to the "untreated" necks, the "irradiated-alone" necks showed reduced RF at almost all levels.ConclusionsThe significant rate of RF in the lower neck warrants particular attention in OCSCC management. Prophylactic irradiation to the lower neck may play a critical role in enhancing regional control and improving patient outcomes.