Colorectal cancer is the third most common cancer and third leading cause of cancer-related deaths for adults in the United States.

Occurring in the colon or the rectum, colorectal cancer is often curable if the cancerous polyps are found early.

Onset
Colorectal cancer begins in the tissues of the colon or rectum. Normally, they grow and divide to form new cells. When this process goes wrong, new cells can form before the body needs them, or old cells do not die. These extra cells can form a mass of tissue creating a tumor. Tumors can be benign (non-cancerous) or malignant (cancerous). When colorectal cancer spreads outside the colon or rectum, it is usually found in nearby lymph nodes and the liver.

Risk Factors
While the exact cause of colorectal cancer remains unknown, studies have found that the following may increase the chance of developing this type of cancer:

  • Being over 50 years old
  • The presence of colorectal polyps (growths on the inner wall of the colon or rectum)
  • Family history of colorectal cancer
  • Smoking
  • Type 2 diabetes
  • Ulcerative colitis or Crohn’s disease
  • Heavy alcohol use
  • Lack of physical activity
  • A diet rich in red meats (beef, liver, etc.) and processed meats (bacon, hot dogs, etc.)

Testing for Cancer
Screening tests are crucial to finding polyps or cancer before symptoms are experienced. Those who should get screened include:

  • Those in their 50s and older
  • People at a higher-than-average risk of developing colorectal cancer

There are several screening tests available, including a colonoscopy, a digital rectal exam and a fecal occult blood test. Should a test come back suggesting cancer, a complete physical exam and/or a biopsy will likely be recommended.

Symptoms
The most common sign of colorectal cancer is a change in bowel habits, such as diarrhea, constipation, finding blood in the stool, or discovering that stools are narrower than usual. Other symptoms include:

  • Feeling that the bowel does not empty completely
  • Frequently having gas pains or cramps, or feeling full or bloated
  • Losing weight for no reason
  • Constantly feeling tired
  • Nausea or vomiting

Treatment
The choice of treatment depends on the location of the tumor and progression of the disease. Typical treatment consists of surgery, chemotherapy, biological therapy or radiation therapy.

Prevention
The best way to prevent cancer in general is to eat well and not smoke. Some factors, such as genetics, cannot be avoided, which is why it is important to be screened. When colorectal cancer is found early, the 5-year survival rate is 90%.