Researchers from the Comprehensive Cancer Center at the University of Michigan Health System found that almost 15 percent, or about one in seven patients, diagnosed with colon cancer are below the age of 50, indicating that more younger patients are developing the disease.
"Colorectal cancer has traditionally been thought of as a disease of the elderly," study author Dr. Samantha Hendren said in a statement. "This study is really a wake-up call to the medical community that a relatively large number of colorectal cancers are occurring in people under 50."
The researchers also discovered that these younger patients often have an advanced form of the disease at the time of their diagnosis. With colorectal cancer screening set at age 50, younger people with the disease only get diagnosed when the symptoms start to show, which means the cancer has already grown, they said.
However, these patients also had higher survival rate because they are given more aggressive treatment.
"To put this in context, breast cancer screening often begins at age 40, and less than 5 percent of invasive breast cancers occur in women under that age. Our study found that about 15 percent of colorectal cancers are diagnosed before the screening age of 50," Hendren said.
This does not necessarily mean the recommended screening age for colon cancer should be lowered, at least not without more investigation, she added.
"This would be a big and costly change, and I don't know whether it would help more people than it would hurt," she says. "A lot of research would be required to understand this before any changes should be made."
More awareness about the early signs of colorectal cancer is needed, the study authors emphasized. These warning signs include bleeding during bowel movement, noticeable changes in bowel movement and anemia.
In the meantime, the reason for an increasing number of younger adults developing colorectal cancer is not known, although some risk factors like poor diet, lack of physical activity, smoking and obesity have been identified, according to Dr. Andrew Chan from Harvard Medical School
"It is unexplained," Chan said. "It's not simply a change in diagnoses, it's a very real increase. There may be an effect of our environment that could be contributing to the increase."
The study was published online Jan. 25 in the journal Cancer.
