Newly Identified Risk Factors May Point to a Heightened Risk for Early-Onset Colorectal Cancer Among Younger Adult Patients

Get Permission

Researchers have identified four warning signs and symptoms that may indicate an elevated risk of early-onset colorectal cancer, according to a new study published by Fritz et al in the Journal of the National Cancer Institute. The findings may be key to helping physicians more effectively detect and diagnose early-onset colorectal cancer in younger adult patients.


According to the American Cancer Society, although the colorectal cancer mortality rate has been dropping for several decades among older adult patients as a result of regular colonoscopies and improved treatment, the incidence of colorectal cancer among younger adults has nearly doubled in recent years. This has led to more advanced-stage diagnoses and an elevated rate of colorectal cancer mortality among this patient population. Such a shift suggests urgency in recognizing symptoms as early as possible.

Individuals born in 1990 may have twofold the risk of developing colon cancer and fourfold the risk of developing rectal cancer compared with young adults born in 1950. That trend has prompted the National Cancer Institute, American Cancer Society, American Gastroenterological Association, and other professional societies to prioritize research on identifying risk factors and improving early detection of the disease. In 2021, the U.S. Preventive Services Task Force lowered the recommended age for colorectal cancer screening from 50 years to 45 years.

“Colorectal cancer is not simply a disease affecting older [patients]; we want younger adults to be aware of and act on these potentially very telling signs and symptoms—particularly because [individuals] under 50 [years] are considered to be at low risk, and they don’t receive routine colorectal cancer screenings,” explained senior study author Yin Cao, ScD, MPH, Associate Professor of Surgery and Medicine in the Division of Public Health Sciences and Gastroenterology at the Washington University School of Medicine.

“It’s also crucial to spread awareness among primary care [physicians], gastroenterologists, and emergency medicine [physicians]. To date, many early-onset colorectal cancers are detected in emergency rooms, and there often are significant diagnostic delays with this cancer [type],” she stressed.

Study Methods and Results

In the new study, the researchers analyzed the de-identified health insurance data of over 5,000 patients with early-onset colorectal cancer and matched controls using the IBM MarketScan Commercial Database—a big-data tool providing longitudinal, de-identified data based on the health insurance claims data of about 113 million insured adult patients aged 18 to 64 years. The researchers found that patients under 50 years demonstrated an increased risk of developing colorectal cancer when they experienced symptoms of abdominal pain, rectal bleeding, diarrhea, and iron deficiency anemia between 3 months and 2 years prior to diagnosis.

Patients who had just one of the symptoms potentially had twofold the risk, those who had two symptoms had 3.5-fold the risk, and those who had three or more symptoms had 6.5-fold the risk of developing the disease. Further, two symptoms in particular—rectal bleeding and iron deficiency anemia—pointed to the need for timely endoscopy and follow-up.

“It usually takes about 3 months to get a diagnosis from the time a [patient] first goes to [their physician] with one or more of the red flag signs and symptoms we’ve identified,” revealed lead study author Cassandra D. L. Fritz, MD, MPHS, Assistant Professor of Medicine in the Division of Gastroenterology at the Washington University School of Medicine. “But in this analysis, we found that some young adults had symptoms for up to 2 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 [patients] who get screened regularly,” she emphasized.


Dr. Cao explained that she currently leads a research group focused on identifying risk factors and molecular variations in early-onset colorectal cancer. Her group is among the first to report that obesity, prolonged sitting, metabolic syndrome, diabetes, sugar-sweetened beverages may all contribute to the rising incidence of early-onset colorectal cancer.

“Since the majority of early-onset colorectal cancer cases have been and will continue to be diagnosed after symptom presentation, it is crucial to recognize these red flag signs and symptoms promptly and conduct a diagnostic work-up as soon as possible,” Dr. Cao underscored. “By doing so, we can diagnose the disease earlier, which in turn can reduce the need for more aggressive treatments and improve patients’ quality of life and survival rates,” she concluded.

Disclosure: The research in this study was funded by the National Center for Advancing Translational Sciences, the National Cancer Institute, and the National Institute of Diabetes and Digestive and Kidney Diseases. For full disclosures of the study authors, visit

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.