[Disease burden of colorectal cancer in China: any changes in recent years?]

Objective: To update the disease burden of colorectal cancer (CRC) in Chinese population by integrating the latest multi-source evidences. Methods: Groups of data from GLOBOCAN, series of Chinese Cancer Registry Annual Report (annual report), Cancer Incidence in Five Continents (CI5), Global Burden of Disease Project 2017 (GBD), China Death Cause Surveillance Datasets and China Health Statistical Yearbooks (yearbook) were used to extract the information. Data on incidence, mortality, disability-adjusted life year (DALY) and percentage distribution of sub-location of CRC were used to analyze the latest disease burden in China, and age-standardized rates by world standard population were mainly used. Joinpoint Trend Analysis Software 4.7.0.0 was applied for time trend analysis. Data related to the economic burden of CRC in China were gathered by literature review. Results: (1) Current status: according to the latest annual report, the incidence and mortality rates of CRC were 17.1 per 100 000 and 7.9 per 100 000, respectively among the covered registration sites in 2015. The incidence ratios of male to female and that of urban to rural were 1.5 and 1.4, with the mortality ratios were 1.6 and 1.4, respectively. Similar to data from the annual report, the mortality rate was reported as 6.9 per 100 000 in 2017 by the surveillance data sets. Data from the GBD project showed that, the DALYs caused by CRC in China in 2017 was 4.254 million person years (doubled compared with that of 1990), accounting for 22.4% of the global burden of CRC. (2) Time trends: according to the annual reports, from 2009 to 2015, the incidence rate and mortality rate of CRC in China decreased by 10.2% and 9.5%, respectively. The same trend was also observed in urban sites, but was opposite in rural areas (increased 20.0% in incidence and 15.2% in mortality). Results from the Joinpoint analysis showed that the averaged annual percentage change (AAPC) was estimated as -1.6% (P<0.05) in the national mortality rate. Similarly, in the incidence and mortality rates of urban sites appeared as AAPC=-1.5% and -1.4% (all P<0.05), but inversely in the incidence rate from the rural sites as AAPC=3.3% (P<0.05). The yearbook data showed a 9.8% increase in urban and 20.6% increase in rural on the mortality in 2017 when compared with 2004, but the Joinpoint analysis showed no statistical significance (P<0.05). (3) Distribution of sub-location of CRC: the annual report showed that among all the new CRC cases in China in 2015, colon, rectal and anal cancer accounted for 49.6%, 49.2% and 1.2%, respectively, while the proportions were 51.3%, 47.6% and 1.1%, respectively in 2009. The proportion of colon cancer was continuously higher in the urban (>52%) than that in the rural areas (<44%). The CI5 Ⅺ data showed that ascending and sigmoid colons were more commonly seen among all the colon cancers. (4) Economic burden: the average annual growth rate of the medical expenditure per CRC patient in China ranged from 6.9% to 9.2%, and the 1-year out-of-pocket expenditure of a newly diagnosed patient accounted for about 60% of their previous-year household income. Conclusions: In China, the overall disease burden of CRC might have been decreased slightly but generally remained stable in the last several years, however, the rising burden appeared in the rural areas should not be ignored. In consistent with findings from a previous review, men and people from the urban areas are considered the target populations for CRC. The finding of higher proportion of colon cancer in urban areas suggests the impact of development of socioeconomic and medical technologies on CRC development and detection. The economic burden of CRC continued to grow.