A retrospective analysis of patients with primary sinonasal adenocarcinoma underwent radiotherapy running title: radiotherapy for sinonasal adenocarcinoma.

The application of radiotherapy in sinonasal adenocarcinoma (SNAC) remained controversial. We aimed to investigate the predictive factors and the indication of radiotherapy in SNAC patients. A monocentric, retrospective study using a primary cohort of SNAC patients who received treatment from June 2000 to December 2022. The study included 81 patients with SNAC. The survival outcomes and the prognostic factors were analyzed using univariate and multivariate analysis. The application of radiotherapy was discussed. The entire cohort’s 5-year overall survival (OS) and progression-free survival (PFS) rates were 75.6% and 64.3%, respectively. Univariate analysis revealed that T4 stage, R2 resection, orbital invasion, and without radiotherapy were poor prognostic factors. On multivariate analysis, surgical margins and radiotherapy were significantly associated with OS and PFS rates. Surgery combined with radiotherapy significantly improved the 5-year OS (66.7% vs. 0%, p < 0.001) and PFS (45.8% vs. 40.0%, p = 0.0019) rates in patients with R2 resection, not in those with R0 or R1 resection. Surgery combined with radiotherapy also was associated with significantly superior 5-year OS (73.7% vs. 46.2%, p = 0.0039) and PFS (60.6% vs. 57.1%, p = 0.013) rates compared with surgery alone in patients with T3-4 stage. Radiotherapy played an important role in the treatment of SNAC patients with R2 resection or T3-4 stage.