Temporal trend of mortality from major cancers in Xuanwei, China.

Although a number of studies have examined the etiology of lung cancer in Xuanwei County, China, other types of cancer in this county have not been reported systematically. This study aimed to investigate the temporal trend of eight major cancers in Xuanwei County using data from three mortality surveys (1973-1975, 1990-1992, and 2004-2005). The Chinese population in 1990 was used as a standard population to calculate agestandardized mortality rates. Cancers of lung, liver, breast, brain, esophagus, leukemia, rectum, and stomach were identified as the leading cancers in this county in terms of mortality rate. During the three time periods, lung cancer remained as the most common type of cancer. The mortality rates for all other types of cancer were lower than those of the national average, but an increasing trend was observed for all the cancers, particularly from 1990-1992 to 2004-2005. The temporal trend could be partly explained by changes in risk factors, but it also may be due to the improvement in cancer diagnosis and screening. Further epidemiological studies are warranted to systematically examine the underlying reasons for the temporal trend of the major cancers in Xuanwei County.