What is Colorectal Cancer?
Colorectal cancer (CRC) is cancer that begins in the colon or rectum. Most cases start as small, noncancerous growths called polyps that can gradually develop into cancer over time. Early detection and removal of polyps can prevent cancer entirely.
Colorectal Cancer Statistics: Incidence, Prevalence, and Risk
Colorectal cancer is one of the most common cancers in the United States and worldwide. About 158,000–160,000 new cases are diagnosed annually in the U.S., with approximately 55,000 deaths each year. The lifetime risk is about 1 in 25 in men and women. Colorectal cancer is now the number one cause of cancer death in people under 50. Over 1.5 million people in the U.S. are survivors living with a history of colorectal cancer.
Colon Polyps and Cancer
What is a polyp? A polyp is a small growth that forms on the inside lining of an organ—most commonly the colon. Think of it like a little bump or mushroom growing on the wall. Most polyps are harmless, but some can turn into cancer over time, which is why doctors remove them when found. Not all polyps turn into cancer, but ~90% of colorectal cancer are though to arise in polyps. This process takes 10-15 years – a great opportunity for prevention.
Not all colon polyps have the same risk of becoming cancer as this table shows.
Colorectal Cancer Screening Guidelines (Early Detection Saves Lives)
Most people at average risk should begin screening at age 45. Continued screening after age 75 is dependent on an individual’s general health and should be individualized. Screening options include colonoscopy every 10 years (if negative), stool-based tests every 1–3 years, or the Sheild blood test (retesting interval is not established). Colonoscopy is considered the gold standard for screening tests.
Colonoscopy is the only screening test that can reduce the risk of developing CRC because pre-cancerous polyps can be detected and removed.
If the screening colonoscopy is clear - or up to 2 Adenomatous polyps < 1 cm or 3 Sessile Serrated polyps/lesion
Choosing the Right Screening Method: Average Risk vs. High Risk
Colonoscopy is an appropriate screening procedure for both average and high risk individuals. Only colonoscopy is appropriate for those at high risk for polyps and colorectal cancer. You are at high risk and should have regular colonoscopy for screening and follow up if one of the following applies:* 1.Personal history of CRC (Colorectal Cancer) 2.Any prior personal history of colon polyps (adenomatous or sessile serrated) 3.Ulcerative Colitis or Crohn’s Disease 4.Any previous childhood, adolescent or young adult cancer 5.1 or more first degree relatives (parents, siblings, children) with CRC at any age (colonoscopy screening to begin at age 40 or 10 y before the earliest CRC diagnosis) 6.1 or more first degree relatives with a history of advanced polyps. •Adenoma ≥10 mm in size •Adenoma with tubulovillous or villous histology •Adenoma with high-grade dysplasia •an SSP/SSL that is ≥1 cm in size and/or contains any dysplasia. *Other screening methods are not appropriate if any of the above apply.
Special Risk Categories
Hereditary CRC syndromes, including Lynch syndrome, familial adenomatous polyposis (FAP), attenuated FAP, MUTYH-associated polyposis, Peutz-Jeghers syndrome, juvenile polyposis syndrome, and serrated polyposis syndrome — these warrant the earliest and most intensive screening, often beginning at age 20–25 with colonoscopy every 1–2 years. Other screening tests are not recommended if any of the above applies.
How to Reduce Your Risk of Colorectal Cancer
Regular screening with removal of precancerous polyps is the most effective preventive strategy. (Insert polyp progression graphic) The role of lifestyle (diet, exercise, habits) Lifestyle/dietary factors associated with lower CRC risk: •Physical activity: Regular physical activity (occupational, recreational, transportation) is associated with decreased CRC risk. •Fruits and vegetables: A diet high in fruits and vegetables is associated with decreased CRC risk. •Dairy products: Higher intake of certain dairy products has been associated with a modestly lower risk of CRC, though the protective effect appears less pronounced than for other established lifestyle factors. •Calcium, vitamin D, and folate: Some studies suggest supplemental use decreases the risk of conventional adenomas. •Smoking cessation: Strongly recommended; risk reduction is seen with early cessation. •Nutrients from food sources: Nutrients should be obtained from natural food sources rather than solely from dietary supplements. Lifestyle/dietary factors associated with higher CRC risk: •Smoking: Long-term cigarette smoking is associated with increased CRC incidence and mortality. •Red meat and processed meat: Long-term consumption is associated with increased CRC risk. •Alcohol: Moderate to heavy consumption is associated with increased CRC risk. •Obesity: Associated with an increased risk for CRC. •Low vitamin D levels: Associated with increased CRC risk.
Symptoms of Colorectal Cancer
Early colorectal cancer usually has no symptoms. When present, symptoms may include changes in bowel habits, blood in stool, abdominal pain, unexplained weight loss, and fatigue.
Treatment Options
Treatment depends on stage. Early-stage cancers may be cured with surgery alone. More advanced cases may require chemotherapy, targeted therapy, or immunotherapy. Treatment is increasingly personalized based on tumor genetics. Improvements in screening, surgical techniques, and modern therapies including targeted treatments and immunotherapy have significantly reduced death rates and improved outcomes over time.
Colorectal Cancer Survival Rates and Outcomes
Overall five-year survival is approximately 65%, but exceeds 90% when detected at an early stage. Survival decreases significantly when cancer spreads, highlighting the importance of screening.
Trend: Rising Risk in Younger Adults
While colorectal cancer rates have declined in older adults due to screening, they are increasing in adults under 50. This trend has led to lowering the recommended screening age to 45.