The role of capecitabine as maintenance therapy in de novo metastatic nasopharyngeal carcinoma:A propensity score matching study

Background:Capecitabine was previously used as a second-line or salvage therapy for metastatic nasopharyngeal carcinoma(NPC)and has shown satisfactory curative effect as maintenance therapy in other metastatic cancers.This study aimed to explore the role of capecitabine as maintenance therapy in de novo metastatic NPC patients with different plasma Epstein-Barr virus(EBV)DNA levels before treatment.Methods:We selected de novo metastatic NPC patients treated with locoregional radiotherapy(LRRT)for this retrospective study.The propensity score matching(PSM)was applied to balance potential confounders between patients who underwent capecitabine maintenance therapy and those who did not with a ratio of 1:3.Overall survival(OS)was the primary endpoint.The association between capecitabine maintenance therapy and survival was assessed using the log-rank test and a Cox proportional hazard model.Results:Among all patients eligible for this study,64 received capecitabine maintenance therapy after LRRT.After PSM,192 patients were identified in the nonmaintenance group.In the matched cohort,patients treated with capecitabine achieved a higher 3-year OS rate compared with patients in the non-maintenance group(68.5%vs.61.8%,P=0.037).Multivariate analysis demonstrated that capecitabine maintenance therapy was an independent prognostic factor.In subgroup analysis,3-year OS rate was comparable between the maintenance and non-maintenance groups in patients with high pretreatment EBV DNA levels(˃30,000 copies/mL)(54.8%vs.45.8%,P=0.835),whereas patients with low pretreatment EBV DNA levels(≤30,000 copies/mL)could benefit from capecitabine maintenance therapy in OS(90.0%vs.68.1%,P=0.003).Conclusion:Capecitabine maintenance therapy may be superior to non-maintenance therapy in prolonging OS for de novo metastatic NPC patients with pretreatment EBV DNA≤30,000 copies/mL.groups in patients with high pretreatment EBV DNA levels(˃30,000 copies/mL)(54.8%vs.45.8%,P=0.835),whereas patients with low pretreatment EBV DNA levels(≤30,000 copies/mL)could benefit from capecitabine maintenance therapy in OS(90.0%vs.68.1%,P=0.003).Conclusion:Capecitabine maintenance therapy may be superior to non-maintenance therapy in prolonging OS for de novo metastatic NPC patients with pretreatment EBV DNA≤30,000 copies/mL.