The death of American actor Chadwick Boseman, at 43, illustrates the increase in the number of colon cancers in adults under the age of 50, which are too often diagnosed at an advanced stage of the disease.
The new study, conducted by scientists at the University of Texas at Austin, took into account information from the US National Cancer Database, data that included more than 70% of new cancer cases in the country, to infer the trends in colorectal cancer since 1970.
More Americans under 50 are being affected by colorectal cancer
The results, which appeared in the journal CANCER of the American Cancer Society, showed that the number of American adults diagnosed with colorectal cancer before age 50 had continued to increase over the past ten years, to go from 10% in 2004 to 12.2% in 2015.
In addition, 51.6% of the people under 50 diagnosed were diagnosed at more advanced stages of their colorectal cancer compared with 40% of people over 50.
African-American and Hispanic adults under 50 also had higher rates of this cancer than non-Hispanic white subjects of the same age.
A decade-long trend
The rates of diagnoses of this type of cancer in young adults have also increased in all socio-professional categories, although the highest rate of diagnoses came from the more affluent categories of the population.
“Several studies have shown that the rates of colorectal cancer in younger adults have risen slowly in the US since the 1970s, but for practicing physicians, it feels like we are seeing more and more young people with colorectal cancer now than we were even 10 years ago,” commented study author Dr. Boone Goodgame. “Until just last year, guidelines recommended colon cancer screening beginning at 50. Now many guidelines do recommend screening at age 45, but most physicians and patients don’t appear to be following those recommendations.”
Dr. Goodgame noted that the cause of the increased rates of this type of cancer in those under the age of fifty is not obvious, although new research suggests that it could be due to several added factors such as ‘increased body mass index and changes in the gastrointestinal microbiota.
Well-known risk factors
Previous research had already established a link between colorectal cancer and a sedentary lifestyle as well as excessive consumption of alcohol and processed meats.
A balanced diet, which especially includes nuts and whole grains, a lot of physical activity, and low alcohol consumption have been associated with lower risk.
The American Cancer Society advises adults over 45 to get tested regularly for colorectal cancer.