RESUMO
BACKGROUND: Whether hepatitis B virus (HBV) infection poses risk to patients with nasopharyngeal carcinoma (NPC) in the intensity-modulated radiotherapy (IMRT) era remains unclear. METHODS: 953 patients with non-metastatic, newly diagnosed NPC who received detection of serologic hepatitis B surface antigen (HBsAg) and treated with IMRT were retrospectively reviewed. 171 patients had HBV infection (HBsAg seropositive). Propensity score matching method (PSM) and stabilized inverse probability of treatment weighting (IPTW) were used to address confounding. The survival rates were evaluated by Kaplan-Meier analysis and the survival curves were compared by Log-rank test. Prognostic factors were explored by multivariate analysis. RESULTS: No significant survival differences were observed between HBsAg-negative group and HBsAg-positive group [5-year overall survival (OS), 87.7% vs. 83.9%, P=0.181; locoregional recurrence-free survival (LRFS), 83.5% vs. 78.3%, P=0.109; distant metastasis-free survival (DMFS), 80.2% vs. 77.9%, P=0.446; progression-free survival (PFS), 77.4% vs. 71.4%, P=0.153], consistent with the results of PSM and IPTW analysis. Further analyses revealed that HBV infection was an independent prognostic factor for poor OS [multivariate analysis; hazard ratio (HR), 3.74; 95% confidence interval (CI), 1.45-9.68; P=0.006], LRFS (HR, 2.86; 95% CI, 1.37-5.95); P=0.005] in patients with stage N1, DMFS (HR, 2.65; 95% CI, 1.15-6.09; P=0.022) and PFS (HR, 2.63; 95% CI, 1.34-5.14; P=0.005). Among HBsAg-positive patients, liver protection improved OS (90.3% vs. 77.2%; P=0.022). CONCLUSIONS: HBV infection is an independent risk factor for patients with stage N1 NPC in the IMRT era. Hepatic protection may benefit the survival of HBsAg-positive patients.