What is Colorectal Cancer?
Colorectal cancer forms in either the colon (large intestine) which is the approximately five-foot-long tube that forms the last passageway of your digestive tract or the rectum, which connects the colon to the anus, the opening in your body where stool is excreted.
Colorectal cancer typically affects older adults, though the incidence of colorectal cancer in individuals under 50 has been steadily rising by approximately 2% to 3% per year over the past two decades. It usually begins as small, noncancerous (benign) clumps of cells called polyps that form on the inside of the colon. Over time, some of these polyps can become colon cancers. Undetected and untreated, it could metastasize (spread) to other parts of the body. It can take up to ten years for a polyp to become cancerous; regular screenings are critical to prevention and early detection.
According to the U.S. Centers for Disease Control (CDC), colorectal cancer is the third most common cancer diagnosed in the United States. About 106,590 new cases of colorectal cancer (54,210 in men and 52,380 in women) were diagnosed in 2024. Colorectal cancer affects more people who are Black than people who are members of other ethnic groups or races.
Risk Factors
- Age: Most colorectal cancer cases are diagnosed in people over age 55. The median age at diagnosis is 66 years old. Diagnosis in people under the age of 50 has increased in recent years.
- Race: Black and African Americans have the highest rate of colorectal cancer among all racial groups in the United States.
- Gender: Colorectal cancer is slightly more common in men and people assigned male at birth (AMAB) than in women and people assigned female at birth (AFAB).
- Family History: People whose relatives have had colorectal cancer or colorectal polyps have an increased risk of colorectal cancer.
- Other Medical Conditions
- Inflammatory Bowel Disease (IBD): Conditions such as ulcerative colitis or Crohn’s disease can increase the risk of PSC and, subsequently, colorectal cancer.
- Diabetes: Some studies suggest that diabetes may increase the risk of colorectal cancer.
- History of Colorectal Cancer or Polyps: People who have previously had colorectal cancer or colon polyps are at an increased risk of developing colorectal cancer.
- Genetic Predispositions: Some genetic changes can be inherited and increase your risk for certain types of cancer. Inherited syndromes, including hereditary nonpolyposis colorectal cancer (or Lynch syndrome) and familial adenomatous polyposis, may put you at higher risk for developing colorectal cancer.
- Lifestyle Factors
- Obesity: Obesity increases a person’s chances of developing many different diseases, including colorectal cancer.
- Sedentary Lifestyle: A lack of movement and exercise is a risk factor for colorectal cancer.
- Diet: A diet heavy in red meat, processed meats, or meats cooked at very high heat can increase a person’s colorectal cancer risk.
- Smoking: Tobacco use, including cigarettes and chewing tobacco, is a colorectal cancer risk factor.
- Alcohol Use: Heavy drinkers are at an increased risk for colorectal cancer.
While these factors can increase the risk, having one or more of them does not mean that someone will develop colorectal cancer. Regular screenings and discussing any concerns with a healthcare provider are important for prevention, early detection, and management of colorectal cancer.