Colorectal cancer incidence rates for both males and females has increased worldwide in the last 20 years, and is mainly caused by increasing Westernisation, according to a new study.
The rise was primarily seen in economically transitioning countries, including Eastern European countries, most parts of Asia, and some countries of South America.
The study is the first to present colorectal cancer incidence trends across all five continents.
Colorectal cancer is the fourth most common cancer in men, and the third most common cancer in women worldwide.
Led by American Cancer Society epidemiologist Melissa Center, the study reviewed colorectal cancer incidence data from 51 cancer registries worldwide with long-term incidence data from the Cancer Incidence in Five Continents (CI5) databases created by the International Agency for Research on Cancer (IARC).
They analysed the change in incidence rates over the past 20 years-1983-87 through 1998-2002-and found that colorectal cancer incidence rates for both males and females increased for 27 of 51 cancer registries considered in the analysis.
The increases were more prominent for men than for women, while some of the increases were quite dramatic.
The researchers also observed substantial regional and ethnic variations in colorectal cancer incidence trends within countries such as Japan, Israel, and Singapore.
The US was the only country where colorectal cancer incidence rates declined in both males and females.
According to the authors, the increase in colorectal cancer in economically transitioning countries may reflect the adoption of western lifestyles and behaviours.
Many of the established and suspected modifiable risk factors for colorectal cancer-including obesity, physical inactivity, smoking, heavy alcohol consumption, a diet high in red or processed meats, and inadequate consumption of fruits and vegetables-are also factors associated with economic development or westernisation.
The study appears in the latest issue of Cancer Epidemiology Biomarkers and Prevention.