Assessment of long-term survival of cancer patients using cancer registry data from eastern China: Period analysis is superior to traditional methods

We aimed to provide a systematical evaluation of the performance of period analysis compared to traditional cohort and complete methods, using cancer registry data from Taizhou, eastern China. Overall, 5-year relative survival (RS) estimate was calculated using cohort analysis, complete analysis and period analysis, respectively; further analyses were stratified by sex, region, age at diagnosis and cancer sites. Deviation value (DV), defined as the deviation between the estimated 5-year RS obtained from each method and the observed actual survival, was calculated to evaluate the accuracy of each method. Overall, 5-year RS derived by period analysis were much closer to the observed actual survival (51.4%), compared to those by complete and cohort methods, with the estimates of 48.7% (DV: ?2.7%), 43.2% (DV: ?8.2%) and 36.3% (DV: ?15.1%), respectively. Further stratifications by sex, age at diagnosis, region and cancer sites also supported period analysis provided more precise estimates, compared to complete and cohort methods. We found, for first time systematically using cancer registry data from eastern China, period analysis provided more up-to-date precise estimates of long-term survival for overall and stratifications by sex, age at diagnosis, region and cancer sites, compared to traditional cohort and complete methods. Nevertheless, further investigations using large cancer registry data across China are warranted for the widespread use of period analysis in China.