BACKGROUND: Declines in incidence rates of nasopharyngeal carcinoma (NPC) were observed in Hong Kong and Taiwan but not other high-risk regions in China, while evidences from low-risk regions in China are still lacking. This study aimed to examine the time trends (1993-2007) of NPC in Wuhan (a low-risk region) and assess the birth cohort and calendar period effects on the observed temporal trends. METHOD: Using data from Wuhan Cancer Registry, age-standardized annual incidence rates of NPC were calculated by the direct method using the WHO World Standard Population (2000) as the reference. Trend in incidence rates of NPC during 1993-2007 was evaluated. Age-period-cohort models were also applied to assess the effects of age, calendar time and birth cohort on the observed temporal trends. RESULTS: A total of 1685 new NPC cases (1210 males and 475 females) were diagnosed during 1993-2007 in Wuhan. The annual percentage change in incidence rates of NPC were 0.15% (95% confidence interval: -3.88% to 4.34%) for males and -1.17% (95% confidence interval: -4.85% to 2.66%) for females. No obvious cohort or period effect on the incidence rates of NPC was observed. CONCLUSION: The incidence rates of NPC remained stable during 1993-2007 in Wuhan, a low-risk region in China.
BACKGROUND: Declines in incidence rates of nasopharyngeal carcinoma (NPC) were observed in Hong Kong and Taiwan but not other high-risk regions in China, while evidences from low-risk regions in China are still lacking. This study aimed to examine the time trends (1993-2007) of NPC in Wuhan (a low-risk region) and assess the birth cohort and calendar period effects on the observed temporal trends. METHOD: Using data from Wuhan Cancer Registry, age-standardized annual incidence rates of NPC were calculated by the direct method using the WHO World Standard Population (2000) as the reference. Trend in incidence rates of NPC during 1993-2007 was evaluated. Age-period-cohort models were also applied to assess the effects of age, calendar time and birth cohort on the observed temporal trends. RESULTS: A total of 1685 new NPC cases (1210 males and 475 females) were diagnosed during 1993-2007 in Wuhan. The annual percentage change in incidence rates of NPC were 0.15% (95% confidence interval: -3.88% to 4.34%) for males and -1.17% (95% confidence interval: -4.85% to 2.66%) for females. No obvious cohort or period effect on the incidence rates of NPC was observed. CONCLUSION: The incidence rates of NPC remained stable during 1993-2007 in Wuhan, a low-risk region in China.