A retrospective cohort study of nasopharyngeal adenocarcinoma: a rare histological type of nasopharyngeal cancer

Objectives: The purpose of this study was to investigate the clinical manifestations, Epstein-Barr virus (EBV) serology, and treatment outcome of patients with nasopharyngeal adenocarcinoma (NPAC). Design: A retrospective study of clinical data from consecutive patients with NPAC identified between 1964 and 2000. Setting: A tertiary cancer center in China. Participants: Forty-eight patients diagnosed with NPAC. Main outcome measures: Crosstabs and chi-square test were conducted to study the association of positive VCA-IgA levels among different pathological types of NPAC, and also to compare the proportions of local control rates in patients treated with different modalities. The survival rate was calculated using the Kaplan-Meier method, and the Log Rank test was used to compare the survival rates considering different factors. To balance the distribution bias, a multivariate COX model survival analysis was also performed. Results: Of the 48 NPAC patients identified, 45% presented with cervical metastasis. Pathologically, 58% of NPAC cases were common type and 42% were salivary gland type. The positive rate for the EBV antibody VCA-IgA in all patients was 53% and only 24% in the salivary gland type of NPAC. The overall local control rate and the 5-year disease-free survival rates were 87% and 65% respectively. Patients treated with surgery plus radiotherapy (RT) had a significantly higher 5-year disease-free survival rate than patients receiving RT alone (89%versus 75% respectively) (P = 0.039). Multivariate analysis confirmed that treatment modality was the significant factor influencing patient survival (P = 0.027) and the pathological type was not a factor predicting survival. Conclusions: Nasopharyngeal adenocarcinoma is a distinct entity in all types of nasopharyngeal carcinoma and EBV serology has limited value in its diagnosis. The combination of surgery and RT should be considered for treatment of early lesions of NPAC.