(RxWiki News) In recent years, rates of some types of cancers have dropped in older patients. But new research suggests the rate of colorectal cancer may be on the rise in younger patients.
The authors of a recent study found that the colorectal cancer rate had decreased overall since 1998, but young adults saw an increase in cases. And the colorectal cancer rate among young adults may nearly double by 2030, according to the researchers.
The researchers said lifestyle factors like poor diet may have contributed to this raised incidence of colorectal cancer and called for raised public awareness of risk factors for it.
"This is an important moment in cancer prevention," said lead study author George J. Chang, MD, associate professor, of the University of Texas M.D. Anderson Cancer Center, in a press release. "We're observing the potential real impact of colorectal cancer among young people if no changes are made in public education and prevention efforts. This is the moment to reverse this alarming trend."
Colorectal cancer is cancer that begins in the colon or rectum. According to the researchers, it is the third most common type of cancer — it kills an estimated 50,000 US patients each year.
Between 1998 and 2006, colorectal cancer rates decreased by about 3 percent per year overall. Dr. Chang and team noted that this was likely due to an increase in cancer screening. Screening for colorectal cancer is recommended for patients older than 50.
Using data on nearly 400,000 patients in the US, Dr. Chang and team found that, between 1975 and 2010, colorectal cancer rates increased by 1.99 percent in patients who were between 20 and 34 years old. The increase was less pronounced in patients between 35 and 49 years old — 0.44 percent.
Overall, patients older than 49 only saw decreases in colorectal cancer rates. The rate among patients older than 75 dropped by 1.15 percent — and 0.97 percent in those who were 50 to 74 years old.
At the current rates, the researchers predicted that the rate of colon cancer among 20- to 34-year-olds would increase by 90 percent by 2030. For rectal cancer, that figure was 124.2 percent.
The researchers also estimated that colorectal cancer rates among older patients would continue to decrease. By 2030, the colon cancer rate among patients older than 50 may decrease by 41.1 percent, they wrote. And the rectal cancer rate for this group could drop by as much as 41 percent.
The study authors noted that the reasons behind the changing rates of colorectal cancer were unclear. But according to Edward Giovannucci, MD, ScD, Professor of Nutrition and Epidemiology at the Harvard School of Public Health, some of the risk factors for colorectal cancer have increased in the past several decades — most notably, obesity, poor diet and sedentary lifestyle — and that might explain the increase in colorectal cancer rates among young people.
"Interestingly, rates in those over age 50 years have declined somewhat, which is likely due to screening," said Dr. Giovannucci, who wasn't involved in this study. "Screening is not routine for those under 50 years of age, so this increase in colorectal cancer incidence due to diet and lifestyle is apparent."
The researchers called for young people to improve their diets by eating more fruits and vegetables and less processed food to reduce their risk for colorectal cancer. The authors said that, although the findings were striking, they did not recommend a change in cancer screening guidelines.
This study was published Nov. 5 in JAMA Surgery.
Grants from the National Institutes of Health and National Cancer Institute funded the research. The authors disclosed no conflicts of interest.
