'Western lifestyle’ may play role in higher bowel cancer rates
A large international study has revealed a clear link between bowel cancer rates and a country’s level of economic development.
The researchers, led by a team at the International Agency for Research on Cancer, found a 10-fold difference worldwide in the numbers of new cases of, and deaths from the disease – with certain countries in Europe, North America and Oceania having a vastly higher predicted rate of new cases than many African countries.
The research, published in the Gut journal, relied on data from the GLOBOCAN database, which records the numbers of new cases and deaths from bowel cancer in 2012 across 184 countries,linked international bowel cancer patterns and trends to economic development.
In countries with very high economic development, the number of new bowel cancer cases was typically six times higher than in countries with very low economic development. Deaths patterns followed the same trend as incidence.
But while the findings suggest that the adoption of a Western lifestyle may have a role to play in the development of the disease, better detection in these regions may also be having a significant impact on the higher levels of reported incidence.
Rebecca Smittenaar, Cancer Research UK’s statistics manager, said: “Poor diet and drinking too much excess alcohol are already known to increase the risk of bowel cancer and this study, by international researchers, highlights the need for prevention and early diagnosis in low and middle income countries. It also emphasises the need for improved treatments, particularly in countries that are showing a rapid increase in cancer cases and deaths as the global burden of bowel cancer continues to increase.”
Estimated new case rates varied from less than 5 per 100,000 of the population in several African countries to over 40 per 100,000 in certain countries in the more developed continents.
The highest rates were in Slovakia, while the lowest (1.5) were in sub-Saharan Africa.
Countries were classified according to the bowel cancer trends seen in the study
The UK was among several countries classed as having rising incidence and falling death rates, along with the likes of Canada, Italy and Sweden. According to Smittenaar: “While the UK shows signs of higher bowel cancer rates compared to other developed countries, this may be due to the NHS bowel screening programme detecting more cases.”
Australia, Japan and the US were among those to have both falling incidence and death rates.
In 2012, there were an estimated 1.4 million new bowel cancer cases and almost 700,000 associated deaths worldwide. The researchers predict that cases are expected to increase to 2.2 million by 2030, with an associated death toll of 1.1 million.
The study’s authors warned of a much greater disease toll in low and middle income countries in the years to come, particularly for emerging economies.
"Without [action] based on this evidence, the number of patients with bowel cancer will continue to increase in future decades beyond those already projected as a result of population ageing and population growth," they say.
Arnold, Melina et al. "Global Patterns And Trends In Colorectal Cancer Incidence And Mortality". Gut (2016): gutjnl-2015-310912. doi:10.1136/gutjnl-2015-310912.