Deaths from colorectal cancer have been falling over the past couple of decades, largely because more people over 50 are getting regular colonoscopies. Unfortunately, this is not the case among those under 50. More people are developing the disease younger, and they are being diagnosed at advanced stages. Many, including actor Chadwick Boseman, are dying of the disease.

The number of younger adults with colorectal cancer has nearly doubled in recent years. Young adults born in 1990 have twice the risk of colon cancer and four times the risk of rectal cancer compared with young adults born in 1950. The American Cancer Societylowered the recommended age for colorectal cancer screening from 50 to 45 in 2019.

Two symptoms in particular serve as warning signs that an individual should get an endoscopy and follow-up right away.

Colorectal cancer is difficult to detect early on because its symptoms generally don’t become noticeable until the cancer has progressed. That’s why screening is so important. As Yin Cao, one of the authors of a recent study on early-onset colorectal cancer explained, “To date, many early-onset colorectal cancers are detected in emergency rooms, and there often are significant diagnostic delays with this cancer.”

“[B]ecause people under 50 are considered to be at low risk…they don’t receive routine colorectal cancer screening,” Cao, an associate professor of surgery at Washington University School of Medicine in St. Louis, added. “It’s also crucial to spread awareness among primary care doctors, gastroenterologists and emergency medicine doctors.”

Among the risk factors that Cao’s group has noted as likely contributing to the rising incidence of early-onset colorectal cancer are: Prolonged sitting, metabolic syndrome, obesity, diabetes and drinking too many sugar-sweetened beverages.

The Washington University team analyzed cases of early-onset colorectal cancer and matched controls using a big-data tool that provides longitudinal, de-identified information based on health insurance claims data from about 113 million insured adults ages 18 to 64 — the IBM MarketScan Commercial Database.

The idea behind the analysis was to try to find ways to identify the disease sooner, while it was more treatable. The researchers uncovered four symptoms that should help detect and diagnose early-onset colorectal cancer among younger adults sooner.

The four red flags that signal an elevated risk of early-onset colorectal cancer are:

Rectal bleeding and iron deficiency anemia in particular are signs that an individual should get an endoscopy and follow-up right away.

“It usually takes about three months to get a diagnosis from the time a person first goes to the doctor with one or more of the red-flag signs and symptoms we’ve identified,” first author Cassandra D. L. Fritz, an assistant professor of medicine in the Division of Gastroenterology, explained. “But in this analysis, we found that some young adults had symptoms for up to two years prior to their diagnoses. That may be part of the reason many of these younger patients had more advanced disease at the time of diagnosis than what we normally see in older people who get screened regularly.”

Cutting back on sugar-sweetened beverages and eating more fiber are two ways to lower your risk. Coffee and weight-loss can also help. If you think you see one of the red flags identified in this study, make an appointment with your doctor or start with an at-home screening test.

The study is published in the Journal of the National Cancer Institute.