title: Trends in incidence and mortality of nasopharyngeal carcinoma over a 20-25 year period (1978/1983-2002) in Sihui and Cangwu counties in southern China.
abstract: BACKGROUND
  Nasopharyngeal carcinoma (NPC) is a rare malignancy in most parts of the world but is common in southern China. A recent report from the Hong Kong Cancer Registry, a high-risk area for NPC in southern China, showed that incidence rate decreased by 29% for males and by 30% for females from 1980-1999, while mortality rate decreased by 43% for males and 50% for females. Changing environmental risk factors and improvements in diagnosis and treatment were speculated to be the major factors contributing to the downward trend of the incidence and mortality rates of NPC. To investigate the secular trends in different Cantonese populations with different socio-economic backgrounds and lifestyles, we report the incidences and mortality rates from two population-based cancer registries in Sihui and Cangwu counties from 1978-2002.
  
  
  METHODS
  Incidence and mortality rates were aggregated by 5-year age groups and 5 calendar years. To adjust for the effect of difference in age composition for different periods, the total and age-specific rates of NPC incidence and mortality rate were adjusted by direct standardization according to the World Standard Population (1960). The Estimated Annual Percentage Change (EAPC) was used as an estimate of the trend.
  
  
  RESULTS
  The incidence rate of NPC has remained stable during the recent two decades in Sihui and in females in Cangwu, with a slight increase observed in males in Cangwu from 17.81 to 19.76 per 100,000. The incidence rate in Sihui is 1.4-2.0 times higher during the corresponding years than in Cangwu, even though the residents of both areas are of Cantonese ethnicity. A progressive decline in mortality rate was observed in females only in Sihui, with an average reduction of 6.3% (p = 0.016) per five-year period.
  
  
  CONCLUSIONS
  To summarize, there is great potential to work in the area of NPC prevention and treatment in southern China to decrease NPC risk and improve survival risk rates in order to reduce M:I ratios. Future efforts on effective prevention, early detection and treatment strategies were also discussed in this paper. Furthermore, the data quality and completeness also need to be improved.
authors.affiliation: Department of Experimental Research, Cancer Center, Sun Yat-sen University, GuangZhou, State Key Laboratory of Oncology in Southern China, China. jiaweihua@tom.com
authors.forename: Wei-Hua
authors.initials: WH
authors.lastname: Jia
authors.forename: Qi-Hong
authors.initials: QH
authors.lastname: Huang
authors.forename: Jian
authors.initials: J
authors.lastname: Liao
authors.forename: Weimin
authors.initials: W
authors.lastname: Ye
authors.forename: Y Y
authors.initials: YY
authors.lastname: Shugart
authors.forename: Qing
authors.initials: Q
authors.lastname: Liu
authors.forename: Li-Zhen
authors.initials: LZ
authors.lastname: Chen
authors.forename: Yan-Hua
authors.initials: YH
authors.lastname: Li
authors.forename: Xiao
authors.initials: X
authors.lastname: Lin
authors.forename: Fa-Lin
authors.initials: FL
authors.lastname: Wen
authors.forename: Hans-Olov
authors.initials: HO
authors.lastname: Adami
authors.forename: Yi
authors.initials: Y
authors.lastname: Zeng
authors.forename: Yi-Xin
authors.initials: YX
authors.lastname: Zeng
mesh_terms: D000328:Adult; D002681:China / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000453:epidemiology* / Q000401:mortality; D012042:Registries; D016019:Survival Analysis