[Period survival analysis of esophageal cancer in Linzhou city of Henan province].

OBJECTIVE: To analyze the survival level and variation of esophageal cancer in Linzhou city of Henan province from 1988 to 2004, and evaluate the effects of diagnosis and treatments on esophageal cancer in this area. METHODS: All incidence and death records for esophageal cancer during 1988 to 2004 were collected from Linzhou Tumor Registry. Cases with duplicate information or death certificate only were excluded. A total of 12,160 cases of esophageal cancer were collected, of which, 6914 cases were male, and 5246 cases were female. The sex-specific and age-specific probabilities of survival in 1992, 1997 and 2002 were calculated and linked to the data of incidence and death on esophageal cancer in this area. Five-year observed survival rate and five-year relative survival rate during 1990 to 1994, 1995 to 1999, 2000 to 2004 were calculated respectively using period survival analysis and cohort survival analysis and Z test. RESULTS: The 5-year relative survival rates among the three-episode were 28.24%, 35.24% and 40.76% respectively during 1988 to 2004. This showed an increasing trend by periods (Z values were 3.94 and 3.07, P < 0.05). The 5-year observed survival rates in men among the three-episode were 13.67%, 18.08% and 22.46% respectively, the 5-year relative survival rates were 29.94%, 36.96% and 38.40%. The 5-year observed survival rates in women among the three-episode were 15.56%, 19.29% and 28.01% respectively, the 5-year relative survival rates were 26.78%, 33.12% and 43.70%. During the two former periods, there was no significant difference in the 5-year observed survival rate and relative survival rate between men and women (Z values of observed survival rate were 1.48 and 0.88, P > 0.05. Z values of relative survival rate were 1.27 and 1.50, P > 0.05). In the third period, the 5-year observed survival rate and relative survival rate in women was higher than that in men (observed survival rate Z = 3.56, P < 0.05; relative survival rate Z = 2.09, P < 0.05). The relative survival rate that calculated using period method (respectively 35.24% and 40.76%) was higher than that using cohort method (respectively 28.77% and 33.35%) from 1995 to 1999, and from 2000 to 2004. CONCLUSION: The survival rate on esophageal cancer in Linzhou city was increasing in the three different periods. This indicated a rising status in the secondary prevention and clinical diagnosis and treatments on esophageal cancer.