Clinicians should consider colorectal cancer as a possible diagnosis when a younger patient presents with symptoms of intestinal bleeding, anemia, or a change in bowel habits.
Research spearheaded at the University of Michigan Comprehensive Cancer Center (UMCCC) found that 10 percent of patients with colorectal cancer were under age 50, and young individuals were more likely to be diagnosed at advanced stages compared with older patients. The results that Samantha Hendren, MD, associate professor of surgery at the University of Michigan Medical School, and her team culled from the Surveillance, Epidemiology, and End Results (SEER) database and published in the journal Cancer (2016;122:929-934) suggest clinicians should consider colon cancer as a possible diagnosis when a patient presents with symptoms of intestinal bleeding, anemia, or a change in bowel habits.
“While colorectal cancer incidence is decreasing overall, thanks to routine screening in individuals age 50 and older, it’s on the rise in younger patients,” said Elena Stoffel, MD, assistant professor of internal medicine and a gastroenterologist at the UMCCC, who was not involved in the Cancer paper.
The SEER findings are important for gastroenterologists and other clinicians to remember: “Don’t forget about the possibility of a colorectal cancer diagnosis in young patients,” she added. “It’s important to keep colon cancer on the radar rather than dismissing bleeding or other symptoms as hemorrhoids.”
IDENTIFYING HIGHER-RISK PATIENTS
The reasons for the increase in colorectal cancer cases among young people are unknown. Incidence is highest among blacks who develop tumors at younger ages, when compared with non-Hispanic whites. In a paper under review, Dr. Stoffel and her colleagues examined the SEER data on outcomes for colorectal cancer patients under 50, and found the survival rate for blacks was lower at every stage of the disease and particularly striking among individuals with stage II cancers.
“While differences in treatment may play a role in racial disparities of outcomes, we have to consider there may be genetic factors that influence cancer risk and outcomes that haven’t been accounted for,” said Dr. Stoffel, who also runs the University of Michigan’s Cancer Genetics Clinic. “The current algorithms used for colorectal cancer risk assessment don’t account for race. So, we’re working to find a better way to assess people’s cancer risk.
“There’s also an observable trend that the rise in colon cancer in young people has tracked alongside the rise in obesity, but we haven’t identified specific mechanisms to explain how obesity might increase risk for polyps or colon cancer,” said Dr. Stoffel.
“There are a number of genetic conditions associated with inherited predisposition to colon cancer, including familial adenomatous polyposis, MYH-associated polyposis, and Lynch syndrome,” Dr. Stoffel said. “Individuals who carry germline mutations associated with hereditary cancer syndromes tend to develop colorectal polyps at young ages, so they should be screened early.”
It is important to remember that 70 percent of colorectal cancers occur in people with no known predisposition or obvious risk factors. Thus, there may be genetic and environmental components to colorectal cancer risk that researchers have yet to identify.
Lowering the recommended age for colorectal cancer screening for everyone is not the answer; however, University of Michigan researchers continue to research ways of identifying patients at higher risk who would benefit from early screening.