Timely assessment of 5‐year relative survival of esophageal cancer patients in Taizhou, Zhejiang province

Abstract

Dear Editor, Regarding the burden of esophageal cancer worldwide in 2020, 604,000 new cases and 544,000 new deaths were estimated according to the latest data on GLOBOCAN. The standardized incidence and mortality of esophageal cancer in China are 2.1 times higher compared to the global average. The 5-year relative survival is an important and comprehensive indicator that reflects the overall effectiveness of cancer screening and treatment. Period analysis is a method providing timely and accurate assessment of 5-year relative survival because it does not need 5-year followup data from cancer registries. 1 While period analysis has widely been used in Western populations, it has rarely been used in China but was for the first time systematically confirmed in China by our group. 2 Therefore, in this study we aimed at providing the latest data on 5-year relative survival for patients with esophageal cancer in Taizhou, Zhejiang province, China, using period analysis.Taizhou City accounts for approximately 10% of the population of Zhejiang Province, China. Actually, we had full access to data from all nine population-based cancer registries from Taizhou City, Zhejiang Province, China. Data on esophageal cancer patients diagnosed during 2004−2018 and followed up till the end of 2018 were retrieved. Regarding the data quality control, we used the criteria that the proportion of death certificate only (DCO) shall be less than 13%, which indicates good quality of cancer registries as recommended by Brenner. 1 Thereby, five cancer registries with DCO cases higher than 13% were excluded after the aforementioned quality control. Eventually we included esophageal cancer patients diagnosed during 2004−2018 from four cancer registries (Luqiao, Yuhuan, Xianju, and Wenling) that demonstrated highquality data. For detailed information on the methodology please refer to the aforementioned paper from our group. 2 In accordance with the International Classification of Diseases, tenth revision (ICD-10), we used the code C15 to classify cases of esophageal cancer. The flow chart of patient selection was shown in Figure 1A. Eventually, over-This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.