Colorectal cancer cases rising in young adults

Diagram of the Colon and Rectum Courtesy of Centers for Disease Control and Prevention
Diagram of the colon and rectum. Source:
 Centers for Disease Control and Prevention

By Melissa Schenkman

Colon cancer is on the rise in U.S. young adults, ages 20-34, according to a recent study from University of Texas MD Anderson Cancer Center in Houston. High fat diets are the suspected culprit, according to a researcher for the study.

Researchers predict that, based on the increases, the number of young adults being diagnosed with colorectal cancer will rise by another 40 percent from 2010 to 2020 and by another 50 percent between 2020 and 2030.

The study published in JAMA Surgery this month examined data from almost 400,000 patients in the National Cancer Institute’s database from 1975 until 2010. The database houses demographic and clinical information on cancer patients from multiple cancer registries.

While researchers found a steady decline in colorectal cancer cases in individuals over age 50, the number of patients ages 20-34 diagnosed with colorectal cancer shows the opposite trend. This age group showed a 2 percent increase in colorectal cancer each year from 1975 to 2010. And, the increased number of cases is seen in localized, regional and metastatic colorectal cancers.

The specific reasons behind increased colorectal cancer in this age group are unknown. But, one of the study’s authors, Dr. Christina Bailey, suspects that diet plays a large role.

“In the United States obesity is a significant problem among young and old people. Young people eat a Western Diet that is high in fat, low in fiber and does not have fruit. They also eat a lot of fast food that may contribute,” Bailey said.

A lack of physical activity, obesity, and a diet low in fiber have been previously linked to colon cancer. Other factors that Bailey thinks may play a role are unknown environmental factors and genes.

However, Bailey says this is not the whole story.

“All of these things contribute, but none explain 100 percent why we are seeing this increase,” Bailey said. “When you’re younger the last thing on your mind is colorectal cancer.”

She also noted that it is also not on the forefront of physicians’ minds either when it comes to this age group.

Dr. Al Benson, a medical oncologist at Northwestern University, said he has observed an increase in the number of younger patients with colorectal cancer in his clinical practice. He said the study raises questions about current screening recommendations.

The United States Preventive Services Task Force, a panel of experts, recommends colorectal cancer screening- fecal occult blood testing, sigmoidoscopy, or colonoscopy- starting at age 50. Physicians perform screening at an earlier age in patients who have genetic risk factors or a hereditary colorectal disease, such as Familial Adenomatous Polyposis.

Screenings enable physicians to find polyps, potentially cancerous lesions, early and that means giving patients a greater chance of being cured, Benson said. Younger patients who present with more advanced disease, have less of a chance to be cured.

“I would hope this information puts an emphasis on looking at younger people with cancer and to begin an in-depth exploration as to look at a very detailed family history, and take tumor samples to do tumor genetic analyses if possible to see any pattern that emerges,” Benson said.

Bailey points out that around five percent of colorectal cancers are hereditary, warranting earlier screening. The young adult population where colorectal cancer is increasing does not fall in the category recommended for screening.

Similar disease trends have been found in breast cancer research, where the number of cases of disease and particularly advanced disease at diagnosis is rising.  Bailey finds this interesting and says it shows the study’s findings on colorectal cancer in the young adult population is not isolated. Further this is why it is important to investigate why this is occurring, she said.

“Our hope is that the study will help spearhead an increase in awareness not only for patients, but for physicians. The hope is for physicians to use this as a way to identify patients who would benefit from earlier colonoscopy,” Bailey said.