Colon Cancer

Cancer and Neoplasms, Oral and Gastrointestinal

Colon cancer occurs when abnormal cells in the intestine grow too quickly and form polyps inside the colon of the large intestine, the final segment of the gastrointestinal system. A polyp is a noncancerous growth that begins in the inner lining of the colon or rectum. Sometimes a polyp can grow into a cancerous tumor that may spread into healthy tissues and invade the lymphatic system. If cancer goes untreated it can spread to other organs and the bones. Colon cancer can go unnoticed without any accompanying symptoms. However, a change in bowel habits and bleeding are two symptoms of the disease. Colon cancer is the third most common type of cancer, affecting both men and women in the United States. The risk for colon cancer is around 1 in 20, but the number of people dying from colon cancer has been dropping at a steady rate due to advanced screening. It is most common in people over 50 years of age but can happen anytime. The great news is there are over one million colon cancer survivors and this form of cancer is very treatable if caught early.

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Early in colon cancer, there may be no symptoms at all. Symptoms usually appear after the tumor has grown to a significant size. Symptoms vary based on where the cancer is located in the colon. These include:

Early Stages

  • Blood in the stool – Blood is either heavy or bright red, streaky, or tarry in appearance
  • Mucus in the stool
  • Changes in bowel habits for longer than three weeks
  • Weight loss (when cancer has spread to other organs)
  • Pain near the anus
  • Bloating
  • Feeling like you need to have a bowel movement (when a tumor is near the anus)

Late Stages

  • Anemia due to blood loss from the tumor
  • Bowel obstruction (vomiting, bloating, constipation, not passing gas, and pain near the naval)
  • Yellow skin/jaundice (this occurs when cancer has spread to the liver)

Risk Factors

Some factors are known to greatly increase the risk of colon cancer. These include:

  • Polyps
  • Age
  • Inflammatory bowel disease (Crohn’s disease or ulcerative colitis)
  • African American ethnicity
  • Intestinal disorders such as ulcerative colitis
  • Family history if colorectal cancer of colorectal polyps
  • Exposure to Radiation
  • Genetic syndrome, including familial adenomatous polyposis or Lynch syndrome

Lifestyle risk factors include:

  • Smoking and alcohol use
  • Highfat and low fiber diet
  • Low physical activity
  • Obesity
  • Diet low in fruit and vegetables


If you have increased risk factors for colon cancer, it is important to be screened regularly before the age of 50. Anyone 50 or older needs regular screening regardless of risk factors. Here are some helpful guidelines for colon cancer screening:

  • Yearly screening
    Fecal occult blood test (gFOBT)
    Fecal immunochemical test (FIT)
  • Every three years
    Stool DNA testing (sDNA)
  • Every five years
    Flexible sigmoidoscopy
    Double-contrast barium enema (High-Risk or history of cancer)
  • Every ten years

Your doctor can tell you which regimen is best for you to follow.

If you do not have any symptoms and the doctor finds polyps in your colon during a routine colonoscopy, the polyps will be biopsied to check for cancer. If you do have symptoms the doctor can order the following tests:

Colonoscopy. The doctor can use a scope to look inside the colon for polyps or tumors. During the colonoscopy, the doctor can remove any polyps and check to see if they are pre-cancerous or cancerous.

CT scan. This scan can check the inside of the colon to look for tumors or irregular areas. It can also look to see if cancer has progressed outside of the colon.

Blood tests. The doctor can order a few tests that can help but don’t always diagnose colon cancer. These are a complete blood count, liver function tests, and tumor markers for colon cancer.


Treatment for colon cancer depends on what stage your cancer is at. Colon cancer is staged according to the following guidelines:

Stage 0. The cancer is confined to just the inner lining of the colon. The treatments at this stage include:

Remove polyps. During a colonoscopy, the doctor will remove any polyps.

Local excision. Any growths that appear “flat” are removed during the colonoscopy.

Open surgery. If you are at high-risk for cancer and polyps are found to be cancerous, the doctor may discuss surgery to remove part of your colon early on to prevent the spread of cancer.

It is not common to do chemotherapy during Stage 0 colon cancer.

Stage I. Stage I colon cancer has spread beyond the inner lining of the colon and into the inside of the colon wall. The treatment at this time is surgery to remove any of the cancerous tissue and some of the healthy tissue outside of the tumor. Doctors do not do chemotherapy at this stage.
The good news is the five-year survival rate at this stage is 93%.

Stage II By this stage, the colon cancer has moved into the muscles inside the wall of the colon. Treatments at this stage include:

Surgery. All the cancerous areas are removed, as well as areas of tissue around cancer.

Chemotherapy. In high-risk individuals, chemotherapy is used at this stage to prevent any further spread of cancer or re-occurrence.
At this stage, the five-year survival rate is around 78%.

Stage III. At this stage, the cancer is beginning to spread to the lymph nodes from where it can metastasize to the rest of the body. Stage IIIA means the cancer is still confined to the colon walls but has reached one or more lymph nodes. Stage IIIB means cancer has spread outside the colon and into one or more lymph nodes. Treatment at this stage includes:

Surgery. Surgery removes the cancerous areas, surrounding tissues, and the lymph nodes that were involved.

Chemotherapy. Chemotherapy is always used at this stage to kill off any remaining cancer cells in the body.

Combination chemotherapy. In advanced cases, a combination of chemotherapy drugsmay be used in conjunction with the standard chemotherapy drug used in earlier stages.

Radiation. If you have a large tumor that moved to any tissue outside the colon, radiation may be used.

At this stage, the five-year survival rate is around 64%.

Stage IV. Stage IV colon cancer has spread outside the colon and into other organs. The organs most often affected are the liver and the lungs. This is known as “metastasis”. Cancer may or may not have spread to the lymph nodes. Treatment at this stage includes:

Surgery. Surgery involves removing the affected part of the colon. The colon will be re-attached at the healthy parts. You may also need surgery to remove any cancer from other organs.

Chemotherapy. At this stage, chemotherapy may not be curative but can help relieve any symptoms and raise the survival rate.

Combination chemotherapy. In people who are less responsive to one type of chemotherapy, doctors now have several types available that are more effective when used in combination.

Clinical trials. Because the survival rate is lower at this stage, your doctor may recommend you for clinical trials of new cancer treatments.

Radiation. Radiation can help relieve any cancer symptoms.
The five-year survival rate at this stage is around 8%.

Recurring colon cancer. This is when colon cancer comes back after treatment. The cancer may come back in the original area of the colon, or appear in another organ. It most often appears in the liver and is most common in people who were treated for more advanced stages of colon cancer.

Alternative Treatments and Home Remedies

No alternative medicine treatments have been found to cure colon cancer at this time. Some dietary supplements may be helpful to relieve symptoms and improve the health of the body. These include:

Selenium. Selenium may help cancer treatments work better.

Omega-3 fatty acids. A recent review study of omega-3 polyunsaturated fatty acids revealed that this oil may be used as an adjuvant treatment for advanced cases of colon cancer. Omega-3 is an anti-inflammatory and may lower the risk of colon cancer. Eat fish at least twice weekly to get this nutrient.

Ginseng tea. May slow cancer growth.

Olive oil. Some studies show that olive oil may protect the digestive system from cancer.

Spices. Some spices may prevent the growth of cancer cells in the colon. These include garlic, rosemary, thyme, peppermint, and turmeric.

Only a doctor can diagnose and treat colon cancer. If you want to use alternative or complementary medicine, be sure to discuss this with your doctor.


Lifestyle Changes and Prevention for Colon Cancer

Eat a healthy diet. Eat plenty of fresh fruits and vegetables, increase your fiber intake, and reduce red meat.

Reduce alcohol and quit smoking. Limit alcoholic drinks to one or two a day and quit smoking.

Start exercising and lose weight. Get 30 minutes of exercise weekly and keep your weight in a healthy range.

Get screened for colon cancer. Talk to your doctor about which guidelines are best for you.


American Cancer Society. (2020). Colorectal cancer: Facts & figures 2020-2022. Retrieved from

Centers for Disease Control and Prevention. (2020, February 10). Colorectal (colon) cancer: What are the risk factors? Retrieved from Centers for Disease Control and Prevention:

Kurkijian, C. &Kummar S. (2009, September-October). Advances in the treatment of metastatic colorectal cancer. American Journal of Therapeutics. 16,(5), 412-420. Retrieved from:

Mayo Clinic Staff. (2020, December 29). Colon cancer. Retrieved from Mayo Clinic:

National Comprehensive Cancer Network. (2018). NCCN guidelines for patients: Colon cancer. Retrieved from


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