Rectal cancer (CRC) is a common and fatal disease. Screening can provide benefits because resection of early adenomas can prevent CRC, and resection of localized cancer may prevent CRC related death. CRC is not common before the age of 40; The incidence rate increased gradually after 40 years old and reached 3.7/1000 every year at 80 years old. The lifetime incidence rate of CRC in general risk patients in the United States is 4.5%, of which 90% cases occur after 50 years old.
Worldwide, CRC is the second most common cancer among women and the third most common cancer among men, causing more than 690000 deaths in 2012. In the United States, CRC is the second leading cause of cancer death. The death caused by CRC accounts for about 8.4% of the total cancer death. About 1 in 3 patients with CRC will die.
A gratifying phenomenon is that in recent years, it is generally recognized that screening is a very important measure to prevent CRC. Between 2004 and 2013, the mortality rate of CRC decreased by an average of 2.7% per year. The microsimulation model Miscan colon suggests that about 53% of the observed decline in CRC mortality may benefit from CRC screening. A study on the time trend of incidence rate and screening rate of CRC in the United States has been reported. From 1987-2010 years, 25-50 cases of CRC cases may be prevented by screening, and the CRC from late stage to early stage is also changed.
At present, there are great differences in colorectal cancer screening programs and acceptance in European countries. In many high-income countries, the overall incidence rate of colorectal cancer is decreasing. However, in the United States and other high-income countries, such as Australia, Canada and Norway, the incidence rate of adults under 50 is increasing.
How does the incidence rate, mortality and staging of colorectal cancer change over time in different countries? In order to discuss the above problems, the international agency for research on cancer conducted transnational research in seven developed countries, and the results were published in the journal Lancet Gastroenterology & Hepatology.
The researchers obtained data on incidence rate of colon and rectal cancer from 20 population based cancer registries in Australia, Canada, Denmark, Norway, New Zealand, Ireland and the United Kingdom. Age trend cohort was used to assess the incidence rate trends of age groups, periods and birth cohort.
The standardized incidence rate of age at different ages in 7 countries has been noted in all research countries, and the incidence rate of colon cancer and rectal cancer has been overall decreasing or stable. However, in the last 10 years with data available, the incidence rate of colon cancer in Denmark (3.1% per year), New Zealand (2.9% per year), Australia (2.9% per year) and the UK (1.8% per year) under the age of 50 increased significantly. In Canada (3.4% per year), Australia (2.6% per year) and the UK (1.4% per year), the annual average percentage change of rectal cancer incidence rate in this age group has also increased significantly.
Meanwhile, the average annual incidence rate of colon cancer among people aged 50-74 years is significantly lower in Australia (1.6% per year), Canada (1.9% per year) and New Zealand (3.4% per year), with a significant decrease in incidence rate of colorectal cancer in Australia (2.4% per year), Canada (1.2% per annum) and the UK (1.2% per annum).
In addition, the increase in colorectal cancer incidence rate in people under 50 years is mainly caused by an increase in distal colon (left) tumor. In all countries, using the nonlinear cohort effect, rectal cancer is more obvious than colon cancer.
In summary, the incidence rate of colorectal cancer in people under 50 years of age in 7 countries has increased significantly.
reference:
Changes in colorectal cancer incidence in seven high-income countries： a population-based study. DOI：https：//doi.org/10.1016/S2468-1253(19)30147-5
Source: Mace medicine
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