ObjectiveTo systematically review the efficacy of different nucleosides (acids) in preventing hepatitis B virus reactivation after chemotherapy in cancer patients. MethodsThe Cochrane Library, PubMed, EMbase, Web of Science, CNKI, WanFang Data, and VIP databases were electronically searched to collect randomized controlled trials (RCTs) of different nucleosides (acids) to prevent HBV reactivation after chemotherapy in cancer patients from inception to June 7th, 2021. Two reviewers independently screened literature, extracted data, and assessed the risk of bias of included studies. Network meta-analysis was then performed by using Stata 16.0 software. ResultsA total of 43 RCTs involving 3 269 patients were included. There were 7 interventions, namely entecavir (ETV), lamivudine (LAM), adefovir dipivoxil (ADV), telbivudine (LdT), tenofovir dipivoxil (TDF), lamivudine combined with entecavir (LAM+ETV), and lamivudine combined with adefovir dipivoxil (LAM+ADV). The results of network meta-analysis showed that the efficacy of reducing the reactivation rate of ETV, LAM, ADV, LdT, TDF, LAM+ETV, LAM+ADV were superior than the control group. The ETV, LAM and ADV were not as effective as LAM+ETV. The leading drug combinations were LAM+ETV (94.8%), LdT (81.5%) and LA+ADV (58.0%). ConclusionsCurrent evidence shows that LAM+ETV, LdT, and LA+ADV are more effective in preventing hepatitis B virus reactivation after chemotherapy in cancer patients. Due to limited quality and quantity of the included studies, more high-quality studies are required to verify the above conclusions.