Colorectal cancer has become the leading cause of cancer related death among people younger than 50. Although routine screening generally begins at age 45 for adults at average risk, warning signs can appear earlier and should be discussed with a health care provider at any age.
To help people recognize possible symptoms and speak with their doctors sooner, the American College of Surgeons (ACS) has introduced free public education resources and a checklist designed for use before primary care appointments.
Colorectal Cancer Is Rising in Younger Adults
“A lot of times when younger patients seek care for bowel symptoms, those symptoms are too often attributed to hemorrhoids or constipation and treated conservatively,” said Marylise Boutros, MD, FACS, FRCSC, FASCRS, a member of the ACS Patient Education Committee, and a colorectal surgeon and vice-chair of Digestive Diseases Research at the Cleveland Clinic Florida, who helped develop the new ACS educational materials. “As more young people are diagnosed with colorectal cancer, awareness of the subtle signs and symptoms of the disease can save lives. The ACS educational materials and checklist were created to help patients clearly raise concerns and keep conversations about colorectal cancer focused.”
The disease is still diagnosed more frequently in older adults, and approximately 1 in 25 men and women will develop colorectal cancer during their lifetime. Even so, diagnoses among younger people have continued to increase.
According to the American Cancer Society, about 1 in 5 colorectal cancer cases now occurs in people younger than 54. Three decades ago, that figure was 11% (about 1 in 10).
Colorectal Cancer Symptoms That Need Attention
The first signs of colorectal cancer can be mild, vague, or easy to mistake for common digestive problems. However, symptoms that are new, persistent, or unusual should not be dismissed without medical evaluation.
The ACS checklist calls attention to several possible warning signs.
Persistent Changes in Bowel Habits
Constipation, diarrhea, unusually narrow stools, or a lasting change in normal bowel habits may indicate an underlying problem. Some people may also feel as though the bowel has not emptied completely.
Rectal pressure or discomfort can also occur. These symptoms may develop when a tumor causes inflammation or partially blocks the bowel.
“In younger patients, these symptoms can sometimes be due to noncancerous conditions,” said Paula Denoya, MD, FACS, FASCRS, Commission on Cancer (CoC) State Chair of the Eastern Long Island-New York chapter, and a colorectal surgeon at Stony Brook University Hospital in New York. “However, any bowel change that is new or different for you deserves medical attention. An annual wellness visit is a good time to raise these concerns.”
Recurring Blood in the Stool
Blood in the stool is an important colorectal cancer warning sign, particularly when it appears more than once.
Research presented at the ACS Clinical Congress 2025 examined patients younger than 50 who received a colonoscopy because they were experiencing symptoms. Rectal bleeding was the strongest predictor of a colorectal cancer diagnosis, raising the odds by 8.5 times.
“Bleeding is the most common symptom of colorectal cancer but can also be caused by other diseases,” said James T. McCormick, DO, FACS, FASCRS, CoC State Chair of the Southwestern Pennsylvania chapter, professor of surgery at Drexel College of Medicine, and chair of the Colorectal Cancer Program at Allegheny Health Network in Pittsburgh, Pennsylvania. “People may notice bright red blood on the toilet paper or in the bowl, or it may cause a red or dark color when mixed in with the stool. Any amount of recurring blood should be evaluated, and colonoscopy may be indicated to determine the underlying cause.”
Changes in Stool Color or Appearance
Changes in the way stool looks may provide additional clues. Bright red stool, dark or tarry stool, or mucus in the stool can be associated with bleeding somewhere in the gastrointestinal tract, colon, or rectum.
These changes do not always mean cancer is present, but they should be evaluated if they continue or recur.
Unexplained Changes in Overall Health
Colorectal cancer and other gastrointestinal conditions can sometimes cause symptoms that affect the entire body.
Unexplained weight loss, persistent tiredness, weakness, reduced appetite, nausea, or vomiting may indicate an underlying medical problem and warrant a conversation with a health care provider.
Family History and Colorectal Cancer Screening
The U.S. Preventive Services Task Force recommends that adults at average risk begin colorectal cancer screening at age 45.
Some people may need to start sooner. This includes those with a family history of colorectal cancer and people with inflammatory bowel conditions such as Crohn’s disease or ulcerative colitis.
Several colorectal cancer screening methods are available. Colonoscopy is still considered the gold standard because it allows doctors to identify cancer and remove precancerous polyps during the same procedure.
“Colorectal cancer is highly treatable when found early, and surgical advances continue to make treatment less invasive,” Dr. Boutros said. “I encourage patients to be proactive and use the checklist to start a conversation with their primary care provider about any concerning bowel changes.”