Colorectal cancer is one of the most common cancers, but it is also one of the most preventable. It usually grows slowly from a small polyp over many years, which gives us a long window to find and remove it before it ever becomes cancer. Screening saves lives, and it works even in people with no symptoms. Here is what to watch for, who is at risk, and how to protect yourself.
Warning Signs to Know
Early colorectal cancer often causes no symptoms, which is exactly why screening matters. When symptoms do appear, they can include:
- Blood in the stool or rectal bleeding
- A lasting change in bowel habits, such as new diarrhea or constipation
- Stools that become narrow
- Belly pain, cramping, or bloating that does not go away
- A feeling that the bowel does not empty fully
- Unexplained weight loss or fatigue
- Iron-deficiency anemia
These symptoms have many causes and usually are not cancer, but they should always be checked. See our guide on blood in the stool.
Risk Factors
Some risk factors you cannot change, and some you can:
- Age: risk rises after 45, though younger cases are increasing.
- Family history of colorectal cancer or polyps.
- Inflammatory bowel disease, such as long-standing ulcerative colitis or Crohn's disease.
- Certain inherited syndromes, like Lynch syndrome.
- Lifestyle factors: smoking, heavy alcohol use, obesity, a diet high in red and processed meat, and low physical activity.
Why Screening Is So Powerful
Most colorectal cancers begin as a polyp, a small growth that is harmless at first but can slowly turn cancerous. During a colonoscopy, I can find and remove these polyps in the same visit. That is what makes colonoscopy unique: it does not just catch cancer early, it can prevent it from ever forming.
When to Start Screening
For people at average risk, screening should begin at age 45. If you have a family history, inflammatory bowel disease, or a genetic syndrome, you may need to start earlier and be screened more often. There are several screening options, but colonoscopy is the only one that both finds and removes polyps. Our screening guidelines article covers the choices.
How to Lower Your Risk
- Get screened on schedule, since this is the single most important step
- Eat more fiber from fruits, vegetables, and whole grains
- Limit red and processed meat
- Stay active and keep a healthy weight
- Do not smoke, and limit alcohol
The Takeaway
Colorectal cancer is common but highly preventable. Know the warning signs, understand your risk, and most of all, get screened when it is time. If you are 45 or older, or have a family history, talk with us about screening.
Talk to a Gastroenterologist in Mountainside, NJ
If your symptoms keep coming back or you are not sure what is causing them, Dr. Amber Khan can help. We see patients from across Union County and New Jersey.