A new study shows the rate of colorectal cancer (CRC) continues to increase in individuals under 50 years old, despite the fact that the overall rate of the disease has been declining in recent years.

Following examination of more than 1 million CRC patient records over 10 years, researchers suggested that health-care providers should be more vigilant about detecting symptoms in younger patients.

The findings were presented at Digestive Disease Week® (DDW) 2016, the largest international gathering of physicians, researchers and academics in the fields of gastroenterology, hepatology, endoscopy and gastrointestinal surgery.

"While the health-care system has done a great deal to address colorectal cancer in people over 50 -- heightening patient awareness and increasing screenings -- our findings show that much more needs to be done to fight this cancer in people under 50, a group not normally considered at risk," said Elie Sutton, MD, the study's lead author and research fellow at Mt. Sinai West Hospital, New York, NY. "Not only did we find that the rate of colorectal cancer in this group is rising, we also saw that within the group that was diagnosed at a younger age, a higher percentage were diagnosed at later the stages of cancer (stage 3 or 4), which is very concerning."

The study found that, over a decade, the number of young-onset cases rose by 11.4 percent, which translates to approximately an average increase of 1.28 percent per year or 136 new cases every additional year.

In contrast, researchers saw that the number of CRC cases in late-onset patients (50 or older) fell by 2.5 percent.

This analysis of the younger group also found a higher incidence of more advanced cancer than in the older group (stage 3: 30.6 percent vs. 25.1 percent; stage 4: 25.6 percent vs. 18.2 percent).

Additionally, they found that young-onset cases were more prevalent in non-white patients than late-onset cases (22.1 percent vs. 16.0 percent).

Dr. Sutton and his team examined 1,010,530 CRC cases in the National Cancer Database from 2004 to 2013 to determine the proportion identified as young-onset compared to those that were late-onset.

They also recorded variables between young-onset and late-onset in factors such as the stage at which the cancer was found, the length of in-patient hospital stay, demographics, and 30-day and 90-day mortality rates.

Studies of CRC about five years ago found a similar trend toward young-onset, Dr. Sutton said. "Between the time of the previous research and our study, we still have not adequately addressed the risk of colorectal cancer in people under the age of 50. It's critical that we reverse this trend so that we are able to reduce, and hopefully eliminate, it in all populations, regardless of age."

While these findings show that CRC is on the rise in people younger than 50, Dr. Sutton notes that the overwhelming majority of CRC cases still occur after age 50.

Colorectal cancer often starts in either the colon or rectum as a growth or polyp that can become cancerous over time.

Finding and removing these polyps from the large intestine through screening, such as a colonoscopy, can help prevent CRC.

In the U.S., according to the National Cancer Institute, CRC is the third-most-common cancer, with more than 132,000 new cases in 2015. In that year, CRC was also the second-leading cause of cancer deaths, second only to lung cancer.

Source: DDW 2016