Study Identifies 4 'Red Flag' Symptoms of Colon Cancer in Younger People

New research has identified four “red flag” signs and symptoms associated with an increased risk of early-onset colorectal cancer and an important finding as new colon cancer diagnoses in people under 50 are rising at an alarming rate.

The four symptoms—abdominal pain, rectal bleeding, diarrhea, and iron deficiency anemia—were identified in a new study, published in the Journal of the National Cancer Institute. The symptoms showed up as early as two years before a colorectal cancer diagnosis.

“Colorectal cancer is not simply a disease affecting older people,” senior investigator Yin Cao, ScD, an associate professor of surgery in the Public Health Sciences Division, and a research member of Siteman Cancer Center at Barnes-Jewish Hospital and Washington University School of Medicine said in news release.

“We want younger adults to be aware of and act on these potentially very telling signs and symptoms,” Cao added. “Particularly because people under 50 are considered to be at low risk, and they don’t receive routine colorectal cancer screening.”

Researchers discovered that, in the three months to two years before receiving a diagnosis, patients who reported abdominal pain, rectal bleeding, diarrhea, and/or iron deficiency anemia had an increased risk of early-onset colorectal cancer.

The more symptoms a person had, the likelier a colorectal cancer diagnosis: A single symptom almost doubled a person’s risk of the disease; having two symptoms increased a person’s risk by more than 3.5 times, and having three or more symptoms increased the risk by more than 6.5 times.

For some, symptoms showed up as many as two years before diagnosis. About 19% of patients experienced their first symptom in the three months to two years before being diagnosed; nearly 50% of patients saw their first sign or symptom within three months of a diagnosis.

Two symptoms in particular—rectal bleeding and iron deficiency anemia—indicate an urgent need for further screening, through endoscopy, Cao said in the news release.

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