Long-term outcomes of patients in different histological subtypes of primary nasopharyngeal adenocarcinoma: A single-center experience with 71 cases

Abstract Objective This study is aimed to evaluate the long-term outcomes and management approaches in different histological subtypes of primary nasopharyngeal adenocarcinoma (NPAC). Materials and methods 71 patients with NPAC at our institution between 1984 and 2016 were reviewed, including adenoid cystic carcinoma (ACC) in 43 patients, mucoepidermoid carcinoma (MEC) in 17 patients, and primary traditional adenocarcinoma (AC) in 11 patients. 37 patients received primary radiotherapy and 34 patients underwent primary surgery. Results The median time of follow-up was 77 months. The 5-year overall survival rate (OS), locoregional failure-free survival rate (LRFFS) and distant metastasis failure-free survival rate (DFFS) were 69.9%, 67.1% and 77.9%, respectively. Patients who received combined modality therapy had better 5-year OS (73.7% vs 66.2%, p = 0.065) and LRFFS (73.1% vs 64.5%, p = 0.047) than patients receiving single modality therapy. Regarding the different histological subtypes, the survival rates of patients with ACC undergoing primary radiotherapy and primary surgery were similar (5-year OS 82.3% vs 68.8%, LRFFS 70.0% vs 70.8%, p＞0.05). As to patients with MEC and AC, those who underwent primary surgery achieved better 5-year OS (75.6% vs 45.5%, p = 0.001) and LRFFS (70.6%% vs 57.1%, p = 0.014) than those who received primary radiotherapy. Multivariate analyses indicated that histological subtypes and radiotherapy technique were independent factors for OS. Conclusions The optimal treatment policy for NPAC remained the combination of radiotherapy and surgery. For patients with ACC, radiotherapy could be considered as the primary treatment. Surgery was suggested to be the primary treatment in patients with MEC and AC.