Nasopharyngeal carcinoma (NPC) is common in southern China. Despite being widely utilized, the positive predictive value (PPV) of the NPC screening scheme of China Ministry of Health based on two EBV IgA is still low. We have newly discovered a new type of anti-EBV antibody (BNLF2b-Ab), which significantly improved specificity in diagnosis of NPC, but its application value in population screening is still unclear.
We performed a prospective head-to-head comparative screening program in Zhongshan City of China. Participants were screened using EBNA1-IgA/VCA-IgA, and anti-BNLF2b in parallel. The testing algorithm of the first scheme cutoff values into two groups: Prob high-risk (above cutoff point) and Prob low-risk (below cutoff point). Cases screened with Prob high-risk or anti-BNLF2b positive were referred to otorhinolaryngologists for diagnostic workup. Comparison between the two schemes in early diagnosis rate, detection rate, PPV and negative predictive value (NPV) were analyzed.
Among the 10340 participants recruited a total of 16 new NPC cases were diagnosed in the first year, of which 12 cases were in early stage (clinical phase I and II), and the early diagnosis rate reached 75% (12/16). Among the 16 diagnosed new cases, 12 and 16 cases of Prob high-risk and anti-BNLF2b positive were detected, respectively, which showed significant differences in detection rate (75.00% vs 100.00%, P=0.03). Also, PPV (3.46% vs 9.52%, P<0.001) and NPV (99.96% vs 100.00%, P=0.04) showed significant differences, respectively. There were 26 cases with double positive results of Prob high-risk and anti-BNLF2b, including 12 newly diagnosed cases, and the PPV reached 46.16%. In addition, anti-BNLF2b scheme reduced the false positive population by about 51.59% (179/347) without reducing the detection rate.
The new anti-BNLF2b scheme showed better efficacy than the two-IgA scheme in the preliminary analysis of population screening in NPC high-incidence area. Follow-up data in the next three to five years are needed for further verification and analysis.
Clinical trial identification
Legal entity responsible for the study
Zhongshan Hospital of Sun Yat-sen University.
National Natural Science Foundation of China.
All authors have declared no conflicts of interest.