[A new surgical strategy for T4 stage posterior buccal carcinoma: anatomical unit resection].

Objective: To investigate the effect of anatomical unit resection on the overall survival rate of patients with T4 stage posterior buccal carcinoma. Methods: We conducted a retrospective study on 79 patients with T4 stage posterior buccal squamous cell carcinoma underwent radical surgery for buccal mucosa cancer and reconstruction with free anterolateral thigh flap in the Department of Oral and Maxillofacial Surgery, the Second Xiangya Hospital, Central South University from March 2014 to December 2019. The 74 patients were males and the 5 patients were females, aged from 28 to 72 years old. The 40 patients in control group underwent traditional extended resection (1.5-2.0 cm safe margin), and 39 patients in the experimental group underwent anatomical unit resection. The clinicopathological parameters of patients were collected and followed up regularly. The overall survival rate was assessed by Log-rank and Cox proportional risk regression model. Multivariate analysis was performed by linear regression model. Results: There were significant differences between experimental group and control group in overall survival rates (61.53% vs 27.50%, chi(2)=6.624, P=0.010) and local disease control rates (74.36% vs 27.50%, chi(2)=17.350, P<0.001). Multiple linear regression analysis showed that local disease control rate was significantly correlated with anatomical unit resection (t=3.880, P<0.001) and lymph node metastasis (t=2.619, P=0.011), and also Cox proportional hazards regression model analysis identified that overall survival rate was significantly correlated with anatomical unit resection (Z=2.421, P=0.016) and lymph node metastasis (Z=2.793, P=0.005). Conclusion: For posterior buccal carcinoma with multiple anatomical units involved, anatomical unit resection can significantly reduce local recurrence and improve overall survival rate of patients.