Patterns of treatment failure in patients with sinonasal squamous cell carcinoma after chemoradiotherapy.

OBJECTIVE To investigate the failure patterns based on precision radiation treatment and to determine the predictive factors of treatment failure for sinonasal squamous cell carcinoma (SNSCC) patients. MATERIALS This was a retrospective study that included 214 cases of treatment failure from 441 consecutive patients. Two experienced radiation oncologists evaluated the tumor volume of cases with local recurrence. The 5-year overall survival (OS), progression-free survival rates (PFS), and distant-metastasis-free survival (DMFS) were estimated. Investigations were performed on the factors that predicted local failure or distant metastasis. RESULTS 140 (31.7%) patients developed local recurrence, 24 (5.4%) experienced regional failure, and 65 (14.7%) underwent distant metastasis. In-field, marginal, and out-of-field failures occurred in 55.7% (78/140), 33.6% (47/140), and 10.7% (15/140) of patients with local recurrence, respectively. In logistic regression analysis, factors statistically significant for total local failure included treatment mode (p < 0.01), chemotherapy (p < 0.01), and surgical margins (p < 0.01). Primary tumors with poor differentiation (p = 0.018) and R2 resection margin (p = 0.009) were more prone to develop distant failure. The 5-year OS, PFS, and DMFS rates were 57.8%, 52.0%, and 56.7% for the whole cohort. In univariate and multivariate analysis, the skull base involvement was an independent predictor for poorer OS and PFS; orbital invasion was an independent predictor for poorer OS. CONCLUSIONS Local recurrence and distant metastasis were the most common failure modes. Treatment mode, chemotherapy, and surgical margins were related to local recurrence. Poor differentiation and R2 resection margin were predictors for distant failure. ADVANCE IN KNOWLEDGE Local recurrence is the most common failure pattern in patients with sinonasal squamous cell carcinoma who accepted chemoradiotherapy, and marginal and out-of-field failures occurred in 44.3% of patients with local recurrence.