The National Comprehensive Cancer Network (NCCN) recommends that colorectal cancer (CRC) screening begin at age 50. This means that less is known about the occurrence of the disease in people under age 50. Unfortunately, one thing that is known is that while the overall rate of colorectal cancer continues to decrease, the incidence of the disease in patients under 50 is, in fact, on the rise. A University of Colorado Cancer Center study presented at the American Society for Clinical Oncology (ASCO) Annual Meeting 2016 seeks to understand this rise in a regional sample of 39,575 patients, finding that in Colorado patients over 50, the rate of CRC is falling at 2.5 percent per year while the rate of CRC in patients under 50 is rising at 0.8 percent per year. The increase in incidence appeared to be driven mostly by an increase in late-stage CRC in the under-50 population with an increase of 2.4 percent per year from 2003 through 2013.
"We hear patients under fifty saying they were told they were too young to have cancer, so not to worry about symptoms. We want young people to be aware that it can happen to them, too. If people are aware of the possibility for colorectal cancer, they're less likely to miss it," says Christopher Lieu, MD, investigator at the CU Cancer Center and assistant professor of medical oncology at the University of Colorado School of Medicine.
The study used data from the Colorado Central Cancer Registry. Overall, the incidence of CRC was about 20 times less in patients under age 50. However, not only is the incidence of young CRC rising, but the majority of these cancers are diagnosed only once they have reached stage IV disease. In fact, the diagnosis of late stage CRC in young patients is rising more than three times as fast as diagnosis of early-stage disease in the same population.
"We're finding this later in young people," Lieu says. Again, this is most likely due in part to screening guidelines that lead to earlier discovery in the over-50 population. Lieu also points out that younger patients (and their doctors) may overlook or discount CRC symptoms that would have been treated more carefully in older patients.
"I think the implication is not that screening age should be decreased. We don't want to do colonoscopies on people who don't need it, which could do more harm than good. What we need is awareness," Lieu says. He points out that awareness can include recognition of symptoms, but may also include awareness of the need for increased care in genetically predisposed populations or those with a family history of the disease. At ASCO 2016, Lieu will also present results showing that CRC in young patients may be genetically distinct from the disease in older patients, leading to a more aggressive profile.
"This is an important finding for the state and an important finding for young patients in general," Lieu says.