RESUMO
Research papers and data concerning NPC epidemiology in China available worldwide were reviewed. It was found that although the results of three national all death-causes sampling surveys in China showed mortality rates in most sampling areas and all as overall to be declining continuously and remarkably, figures for 1987-2000 in some selected areas of China released by the World Health Organization were relatively stable, and the NPC incidence and mortality rates reported by Zhongshan and Sihui cities of Guangdong Province in China had shown ascending or stable trends, respectively. Differences with regard to change in NPC incidence and mortality rates over time may be caused by variation in the data quality from divergent sources, but the exact reasons clearly warrant further analysis.
Assuntos
Mortalidade/tendências , Neoplasias Nasofaríngeas/mortalidade , China , Humanos , Incidência , Taxa de SobrevidaRESUMO
OBJECTIVE: To analyze the change of EB virus VCA/IgA and EA/IgA titer during the development of nasopharyngeal carcinoma (NPC), and the role in screening for NPC. METHODS: VCA/IgA and EA/IgA were monitored in a period of 12 years by immunoenzymatic titration from the sera of 54 NPC patients after primary serological screening. RESULTS: VCA/IgA and EA/IgA titer had shown gradual increment 1 - 7 years before NPC was pathologically diagnosed. The mean titer of VCA/IgA was 1:21.04, 7 - 4 years before diagnosis. VCA/IgA titer ascended quickly within 3 years before diagnosis. The geometric mean titer (GMT) of VCA/IgA and EA/IgA were 1:76.86 and 1:6.49 when NPC was diagnosed, which descended quickly after radiotherapy and, in 4 years, approached the average titer of VCA/IgA positive population. CONCLUSION: VCA/IgA titer rises uninterruptedly 3 years before NPC is diagnosed pathologically in most patients but their EA/IgA titer rises slowly. The detection of VCA/IgA titer can be used to find early NPC, whereas EA/IgA can not. The pre-clinical phase of NPC is 3 years according to this dynamic study.
