Objective To investigate the relationship between the expression of long non-coding RNA C-terminal binding protein 1 antisense RNA2(LncRNA CTBP1-AS2)and microRNA-140-5p(miR-140-5p)levels in nasopharyngeal carcinoma tissues and the radiotherapeutic effect and prognosis.Methods A total of 222 nasopharyngeal carcinoma patients diagnosed in Nantong Cancer Hospital from March 2018 to March 2020 were collected as the nasopharyngeal carcinoma group.The clinical data of these patients were recorded,the radiotherapeutic effect and prognosis were evaluated,and they were grouped into the survival group(n=194)and the death group(n=28).Meanwhile,another 219 patients with nasopharyngeal inflammation were collected as the control group.Correlation between LncRNA CTBP1-AS2 and miR-140-5p expression levels in nasopharyngeal carcinoma patients was calculated using Pearson correlation analysis.Kaplan-Meier survival curve was applied to analyze the relationship between the expression levels of LncRNA CTBP1-AS2 and miR-140-5p in nasopharyngeal carcinoma tissue and prognosis.Multivariate analysis was conducted on the prognosis of nasopharyngeal carcinoma patients using Cox proportional risk regression model.Results The expression level of LncRNA CTBP1-AS2 in the tissues of patients in nasopharyngeal carcinoma group(2.25±0.46)was higher than that in the control group(1.02±0.22),while the expression level of miR-140-5p(0.67±0.19)was lower than that in the control group(1.01±0.23),and the differences were statistically significant(t=35.742,16.934,all P<0.001).There was a negative correlation between LncRNA CTBP1-AS2 and miR-140-5p expression levels in nasopharyngeal carcinoma patients(r=-0.624,P<0.001).The total effective rate(74.11%)and 3-year survival rate(77.68%)of nasopharyngeal carcinoma patients with high expression of LncRNA CTBP1-AS2 after radiotherapy were lower than those with low expression(93.64%,97.27%),and the differences were statistically significant(χ2=15.578,19.331,all P<0.001).The total effective rate(93.58%)and 3-year survival rate(96.33%)of patients with high expression of miR-140-5p after radiotherapy were higher than those of patients with low expression(74.34%,78.76%),and the differences were statistically significant(χ2=15.119,15.538,all P<0.001).The magnetic resonance amide proton transfer(APT)value(2.10±0.26),the proportion of patients with radiotherapy failure(85.71%),high expression of LncRNA CTBP1-AS2(89.29%),and low expression of miR-140-5p(85.71%)in the death group were higher than those in the survival group(1.82±0.31,6.19%,44.85%,45.88%),and the differences were statistically significant(t/χ2=4.551,108.127,19.331,15.538,all P<0.001).The level of LncRNA CTBP1-AS2 was a risk factor for mortality within 3 years in nasopharyngeal carcinoma patients(HR=2.762,95%CI:1.510～5.051,P=0.001),while the level of miR-140-5p was a protective factor for mortality within 3 years in nasopharyngeal carcinoma patients(HR=0.817,95%CI:0.718～0.930,P=0.002).Conclusion LncRNA CTBP1-AS2 was highly expressed,while miR-140-5p was lowly expressed in nasopharyngeal carcinoma tissue,indicating the two may be closely related to the radiotherapeutic effect and prognosis.