Abstract:
Each year, colorectal cancers (CRCs) affect over a quarter of a million people.
The risk of developing CRC in industrialized nations is approximately 5%. When the disease
is localised, treatment success rates range from 70–90%; however, advanced CRC has a high
mortality rate, consistently ranking in the top three causes of cancer-related deaths. There is
a large geographic difference in global distribution, and CRC is predominantly associated
with developed countries and a Western lifestyle and diet. As such, the developed world
accounts for more than 63% of all cases of CRC. Geographic variations also predict cancer
outcomes, which differ between racial and ethnic groups. This variation is due to inequalities
in wealth, differences in the exposure to risk factors and barriers to high-quality cancer
prevention, early detection and treatment. The aim of this paper was to review CRC in lowand middle-income countries such as South Africa, India, Brazil and China, and compare
them with high-income countries such as the United States of America and the United
Kingdom. It is important to note that these economically less developed countries, with
historically low CRC rates, are experiencing an increased frequency of CRC. The review
also discusses biological markers and genetic pathways involved in the development of
colorectal cancer. Genes known to be responsible for the most common forms of inherited
CRCs have also been identified but more remain to be identified. This would provide more
candidate genes to be added to known biomarkers. CRC burden can be controlled through
the widespread application of existing knowledge, such as reduced smoking habits, vaccination, early detection and promoting physical activity, accompanied by a healthy diet. An
increased understanding of the molecular mechanisms and events underlying colorectal
carcinogenesis will enable the development of new targets and therapeutic drugs.
