The improved cure fraction for esophageal cancer in Linzhou city

Background: Survival of esophageal cancer in Linzhou was seen to increase over the past few decades and is higher than the average level of China due to the implementation of comprehensive prevention and control measures. In population-based studies, relative survival is a common index to approximate disease-specific survival. However, the cure fraction maybe great interest to patients and physicians. This study aimed to investigate the cure fraction of esophageal cancer in Linzou city during 2003-2012 with a cure model. Methods: We carried out a population-based study of 8067 esophageal cancer patients in the Linzhou city during 2003-2012. Flexible parametric cure models were used to estimate cure proportions and median survival times of uncured by year of diagnosed and age. In each model, an interaction between calendar year and age were included. All variables in the model were included both as constant and time-varying effects. Results: The 5-year relative survival rate was increased in every age group from 2003 to 2012. The huge increase in the cure proportion was observed in each age group. At the year of 2011-2012, 79.8%, 58.0%, 123.4% and 162.7% improvements of cure proportion were seen in age group 19-49, 50-59, 60-69 and 70-99 years compared with year of 2003-2004. Meanwhile, survival of 'uncured' patients changed little in all age group. Conclusions: The improvement of survival in Linzhou city during 2003-2012 was mainly due to an increasing cure proportion. Huge improvement of cure fraction within short period is likely due to the organized screening of esophageal cancer in Linzhou city.