Time trend analysis of incidence rate for nasopharyngeal carcinoma in urban Shanghai

Objective To explore the secular trend of incidence for nasopharyngeal carcinoma (NPC) in urban Shanghai during 1973-2005. Methods The incidence data from the population-based cancer registries in Shanghai was used in our analysis. We calculated the crude incidence rates, age-adjusted incidence rates, trucated rates and cumulative rates of NPC. The annual percentage change (APC) was used as an estimate of the secular trend. Results Over 33 years, a total of 7889 incident NPC cases in urban Shanghai were registered for 5555 males and 2334 females, respectively. The incidence of NPC had remained stable in males during the period (APC=-0.250%, P= 0.340), but a decreasing trend was observed in females with an average reduction of -1.577% (P=0.000) per year. During the period of 1973-1976 to 2001-2005, the crude incidence rates changed from 4.56 to 6.18 and from 3.96 to 2.41 per 100 000 in males and females, and the age-adjusted rates from 4.12 to 3.96 and from 2.18 to 3.42 per 100 000 in males and females, respectively. Conclusion From 1973 to 2005, the incidence of NPC was stable in males while having a decline in females, indicating that further epidemioiogical study and prevention for NPC should be addressed. Key words: Nasopharyngeal carcinoma;  Incidence;  Time trend