Incidence Trends for EBV-Associated Malignancies Extranodal NK/T-Cell Lymphoma and Nasopharyngeal Carcinoma in Taiwan

Both nasopharyngeal carcinoma (NPC) and extranodal NK/T-cell lymphoma (ENKTL) are associated with the Epstein-Barr virus (EBV). The purpose of this study was to evaluate the incidence patterns of ENKTL and NPC in Taiwan during the previous 15-30 years. We conducted an epidemiological study using population-based registry data from the Taiwan Cancer Registry to assess the incidence of ENKTL from 2008 to 2021 and NPC from 1995 to 2021. The secular trends in the annual incidence rates were described as average annual percent change (AAPC). During the study period, 872 new ENKTL diagnoses and 39412 new NPC diagnoses were reported. The annual age-adjusted incidence rate of ENKTL and NPC both decreased significantly, with AAPC of -2.47 (p = 0.014) and -1.16 (p < 0.001), respectively. For NPC, the incidence rate decreased from 1995 to 2021 in the age groups of 20-44, 45-64, and 65+ years from 5.23 per 100,000 persons to 4.42 per 100,000 persons (AAPC of -0.45, p = 0.011), from 15.28 per 100,000 persons to 11.36 per 100,000 persons (AAPC of -1.21, p < 0.001), and from 10.48 per 100,000 persons to 7.24 per 100,000 persons (AAPC of -1.91 (p < 0.001), respectively. A substantial decrease in the age-specific incidence of ENKTL was seen in the 45-64 year age group, from 0.46 per 100,000 persons in 2008 to 0.32 per 100,000 persons in 2021 (AAPC of -3.37; p = 0.008). There was also a suggestive decrease in incidence between 2009 and 2021 in the 20-44 and 65+ age groups from 0.16 per 100,000 people to 0.11 per 100,000 people and from 0.87 per 100,000 people to 0.79 per 100,000 people, respectively. Interestingly, the EBV seroprevalence in Taiwan appears to remain stable from 1984 to 2007, with a seroprevalence of over 90% among persons Nonetheless, there appears to be a downward trend in seroprevalence in early childhood, with prevalence falling by approximately 20% in children aged 4 years and by nearly half in children younger than 2 years of age. This suggests that the downward trend of NPC/ENKTL may be affected by the decline in early EBV infection rates. In conclusion, our population-based data showed a decrease in incidence of NPC/ENKTL in the last 20 years in Taiwan. Given the EBV seroprevalence remained stable but early EBV infection declined during the same period in Taiwan, these findings suggest delayed EBV infection or factors other than EBV might be important in the downward trend of NPC/ENKTL in Taiwan and warrant further investigation.

No relevant conflicts of interest to declare.