Abstract: Objective To analyze the incidence characteristics and changing trends of malignant tumors of digestive system in Hefei from 2011 to 2015. Methods The incidence data of malignant tumors of digestive system in Hefei from 2011 to 2015 were collected, and the crude incidence rate (CIR), age⁃standardized incidence rate by Chinese standard population (ASIRC), and age⁃standardized incidence rate by Segi's world population (ASIRW) were calculated. The annual percent change (APC) of the ASIRC was calculated by using Joinpoint software to evaluate the trend of the incidence of malignant tumors in the digestive system over time, and the APC and average annual percent change (AAPC) of crude incidence were also calculated to evaluate the trends of age of digestive malignant tumors incidence with respect to gender and urban⁃rural areas. Results From 2011 to 2015, the number of digestive system malignancies in Hefei was 53, 990 cases, with CIR of 162.29/10⁵, ASIRC of 135.57/10⁵ and ASIRW of 135.93/10⁵, accounting for 55.66% of the total number of new malignant cases. The overall incidence gradually increased during 5 years, but the trend was not significant (APC=2.36%, 95%CI: -7.75%-13.58%, P=0.527). The top 5 tumors in incidence were gastric cancer, esophageal cancer, colorectal cancer, liver cancer, and pancreatic cancer, accounting for 53.64% of the total number of new malignant cases, among which the incidence of colorectal cancer continued to rise over time(APC=9.82%, 95%CI: 0.86%-19.57%, P=0.039), while the incidence of other cancers were increased, though insignificantly (all P>0.05). The overall incidence increased gradually with age over the 5⁃year period and rapidly after the age of 30 years old. The incidence rates of age⁃specific in different genders and urban/rural areas were consistent, and the incidence increased rapidly in the age group of ≥25 years old (APC=9.60%, 95%CI: 8.01%-11.20%, P<0.001) and the age group of ≥20 years old (APC=10.74%, 95%CI: 9.30%-12.21%, P<0.001), respectively, among which the incidence in the age group of ≥40 years old were higher in males than in females. The incidence of malignant tumor of digestive system, gastric cancer and esophageal cancer were higher in rural areas than in urban areas in the age group of ≥20 years old, while the incidence of colorectal cancer and pancreatic cancer were higher in urban areas than in rural areas in the age group of ≥ 50 years old. Conclusions  From 2011 to 2015, the incidence of malignant tumors of the digestive system in Hefei increased gradually, but the overall trend of change was relatively stable, showing that male were higher than female and rural areas were higher than urban areas. The incidence trends of age⁃specific in different genders and areas were consistent. In the future, Hefei still needs to strengthen the prevention and treatment of malignant tumors of the digestive system. 

Key words: Malignant tumors of the digestive system, Incidence, Age, Joinpoint analysis