[Clinical features of advanced adenoid cystic carcinoma in the nasal cavity and paranasal sinuses: analysis of 21 cases].

OBJECTIVE: To evaluate the clinical characteristics, treatment and prognosis of advanced adenoid cystic carcinoma (ACC) in the nasal cavity and paranasal sinuses. METHODS: Twenty-one patients with advanced ACC in the nasal cavity and paranasal sinuses were treated in our department between February, 2007 and May, 2016. The clinical manifestations, T-stage, N-status, treatment, histological grade, recurrence and distant metastasis of the tumors were analyzed. Univariate survival analysis was performed with Kaplan-Meier method and Log-rank test, and the factors affecting the prognosis of the patients were explored using multivariate analysis with Cox proportional hazard model. RESULTS: Among the 21 patients, 10 (47.6%) had ACC containing less than 30% of solid tumor tissues and their overall survival rates at 1, 3, and 5 years were 100%, 100% and 70%, respectively; in the 11 cases (52.4%) with solid tumor tissues no less than 30%, the overall survival rates at 1, 3, and 5 years were 70%, 40% and 10%, respectively, showing significant differences between the two groups (P=0.02). The Log-rank test and survival analysis using the covariate variable model curve indicated a significant impact of the pathological classification on the patients' prognosis. The patients in T3 stage had slightly better prognosis than those in T4 stage; tumors originating from the maxillary sinus had a slightly better prognosis than those from the sphenoid sinus. Surgery combined with radiotherapy resulted in better outcomes of the patients than surgery or radiotherapy alone. Multiariable Cox regression model analysis showed that the pathological classification (P=0.045) and the disease course (P=0.028) were closely related with the prognosis of the patients. CONCLUSION: ACC in the nasal cavity and paranasal sinuses has a low incidence without specific symptoms. Its early diagnosis can be difficult, and most of the patients are in advanced stage upon diagnosis. We recommend comprehensive treatments combining surgery, postoperative radiotherapy and chemotherapy for these patients. The pathological classification, disease course, lesion site, clinical stage, treatment approache, compromise of the peripheral nerves, status at the edge of resection, and postoperative radiotherapy dose can all be factors affecting the prognosis of patients with advanced ACC.