CRC rates on the rise

The incidence of colorectal cancer (CRC) is increasing in many countries around the world, according to a new study by the American Cancer Society. The study's authors believe the rise is due to the uptake of so-called 'western' diets and lifestyles, such as high red meat consumption and low levels of exercise. Previous studies have documented significant variations in CRC incidence rates and trends, regionally and across countries. However, no study has examined the worldwide pattern using the most recently updated incidence data from the International Agency for Research on Cancer (IARC).

Scientists reviewed data from 51 cancer registries around the world using databases created by the IARC in order to analyse rates of CRC from 1983 to 1987 through to 1998 to 2002. They found that CRC incidence rates statistically significantly increased for both men and women in 27 of the 51 cancer registries, although the increases were more prominent among men. Of particular note were Slovakia, Slovenia and the Czech Republic in the EU, and Japan, Kuwait and Israel in Asia. In Slovenia, CRC incidence increased by 70 per cent among men and 28 per cent among women, and in Miyagi, Japan, rates in men and women rose by 92 and 47 per cent, respectively.

The researchers, whose findings are published in the June edition of Cancer Epidemiology Biomarkers and Prevention (CEBP; 2009;18:1688-1694), also found that there were substantial variations in CRC incidences between different regional and ethnic groups in some countries, including Japan, Israel and Singapore. The only country where CRC rates statistically significantly declined in both sexes was the US, but the US had a very high rate of CRC to start with. In contrast, economically transitioning countries, such as eastern European nations, most parts of Asia and some South American countries, saw large rises in CRC rates. The study authors believe that this may reflect the increasing adoption of western lifestyles and behaviours in these countries.

Further, a separate study, also published in the same edition of CEBP (2009;18:1695-1698), has focused on the CRC incidence rates among young men and women in the US. The recent, accelerated decline in CRC incidence rates has largely been attributed to an increase in screening among adults aged 50 years and older. Scientists used data to report on CRC incidence trends from 1992 through 2005 among adults under the age of 50 years, for whom screening is not recommended for persons at average risk, by sex, race/ethnicity, age, stage at diagnosis and anatomic subsite.

Overall, incidence rates of CRC per 100,000 young individuals (ages 20 to 49 years) increased 1.5 and 1.6 per cent per year in men and women, respectively, from 1992 to 2005. Among non-Hispanic whites, rates increased for both men and women in each ten-year age grouping (20 to 29, 30 to 39 and 40 to 49 years) and for every stage of diagnosis. In contrast to the overall decreasing trend in CRC incidence in the US, rates are increasing among men and women under the age of 50 years. Further studies are necessary to elucidate causes for this trend, and identify potential prevention and early detection strategies.

Alice Rossiter - Cancer Drug News Editor