The Grapevine

Colorectal Cancer Deaths Declining In US, New Cases Expected To Surge In Countries Undergoing Rapid Development

global health
Incidence and mortality rates of colorectal cancer vary widely worldwide, with rates in low-income and middle-income countries spiking. Courtesy of NASA.

Lifestyle diseases are those that occur with greater frequency among the industrialized nations of the west, where people generally live longer despite unhealthy behaviors, such as physical inactivity and low consumption of fruits and vegetables, and high consumption of red or processed meats.  One such lifestyle disease, colorectal cancer, acts as a kind of “canary in a coal mine,” a clear marker of transition among the nations of the world undergoing certain social and economic changes. 

In fact, a new report from an international team of scientists reveals incidence and mortality rates for colorectal cancer are rapidly rising in many of the low-income and middle-income countries transitioning toward a western lifestyle. 

Researchers from the International Agency for Research on Cancer in France and the Surveillance Research Program of the American Cancer Society teamed up to determine how people around the world are affected by colorectal cancers malignancies of either the colon or rectum. To accomplish this, the team extracted data from the GLOBOCAN database which contains information from 2012 on incidence and deaths from the disease for 184 countries. They also looked at time trends in 37 countries; here, they used data from the World Health Organization’s mortality database along with other sources.

Completing their analysis, the researchers say colorectal cancer is the third most commonly diagnosed cancer and the fourth leading cause of cancer death in the world. In 2012, an estimated 1.4 million new cases were diagnosed worldwide and almost 700,000 people died from the disease.

Yet, these estimated rates varied wildly around the globe. In several African countries, less than 5 per 100,000 people were diagnosed with the disease, while in the high income countries of Europe, Northern America, and Oceania (Australia and New Zealand), rates ran as high as more than 40 per 100,000 people.

By 2030, new cases will surge to 2.2 million, the team predicts, with a total death toll of 1.1 million.

Other Findings

  • Rates in women tended to be around 25 percent lower than those of men.
  • Lowest rates could be found in sub-Saharan Africa, Gambia, and Mozambique, where the team estimated a diagnosis rate of 1.5 for every 100,000 people.
  • Highest rates could be found in Slovakia (61.6/100,000), Hungary (58.9/100,000), and Korea (58.7/100,000).
  • Three distinct patterns appear across the globe: 14 nations showed rising or stable incidence and death rates; 14 countries showed rising incidence and falling death rates; and 9 nations showed falling incidence and death rates.

For the United States, Canada, Australia, New Zealand, most European countries (other than Croatia, Romania, Latvia, Estonia and Russia), and Japan, the researchers calculated mortality declines among both sexes. The team attributes the lower death rates to better cancer treatment, though improved screening in the form of colonoscopy, which permits a doctor to remove pre-cancerous polyps, may also play a role.

“Diverse global colorectal cancer patterns and trends point towards widening disparities and an increasing burden in countries in transition,” concluded the researchers. “Generally, colorectal cancer incidence and mortality rates correlate with the adoption of a western lifestyle.” 

With a western lifestyle no longer limited to the west, "lifestlye diseases" have begun to proliferate in non-Western nations. Increasingly, then, global health will depend upon a unified effort to modify the risk behaviors that lead to this cancer, including drinking alcohol, physical inactivity, poor diet, and smoking.

Source: Arnold M, Sierra MS, Laversanne M, et al. Global patterns and trends in colorectal cancer incidence and mortality. Gut. 2016.

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