Definition and Overview

Colon cancer is a type of cancer that originates in the large intestine (colon). It usually begins as small adenomatous polyps, which are noncancerous. However, as these grow, they can take on cancerous properties. Polyps can also form in the large intestine, but only a few inches from the lower part. In these cases, the cancer is referred to as colorectal cancer.

Symptoms of Colon Cancer

When colon cancer is still in the early stages, there will not likely be any symptoms at all. Colon cancer symptoms will appear as the condition progresses, and these can include:

  • Fatigue

  • Weight loss

  • Frequent gas, abdominal pain or cramps

  • Blood in the stool or from the rectum

  • Constipation or diarrhoea

  • Incomplete bowel discharge

When to see your doctor

Patients who experience bowel cancer symptoms described above must see their doctor to undergo bowel cancer screening. This type of cancer screening is also recommended for older people (50 years old and above) and those with a history of cancer in their family even if they do not have any symptoms. As a preventative measure, undergoing rectal cancer screening allows patients to catch the condition during its early stages when it is most responsive to treatment.

Causes of Colon Cancer

Just like any type of cancer, the exact causes of colon cancer are yet to be determined. However, the medical community has established the way it spreads. The body’s mechanisms involve the continuous growth and division of cells. However, for some unknown factors, this process does not only occur in healthy cells but also in damaged cells. This is how cancer cells develop and spread to other organs.

Other than external factors, colon cancer can also be inherited, which is why individuals with a history of the disease in their family are encouraged to undergo regular screening even if they do not experience any symptoms. Inherited colon cancer comes in two forms; familial adenomatous polyposis (FAP) and hereditary nonpolyposis colorectal cancer (HNPCC). The FAP type is a bit more concerning since people with this type of cancer usually develop thousands of polyps, and any one of them can turn out to be cancerous before the person reaches 40.

Are you at risk?

Colon cancer has numerous risk factors associated with it. These include obesity, smoking, diabetes, sedentary lifestyle, alcohol consumption, radiation therapy, low fibre diet, family history, inflammatory diseases of the intestine, and old age. If you have one or more of these factors, the higher your risk of having this type of cancer.

Which doctor should you see?

The first doctor you should see if you notice any signs of colon cancer or if you’re concerned about having risk factors and want to undergo cancer screening is your physician. Your doctor will assess your condition and refer you to a specialist. The specialist can be a gastroenterologist (specialist in digestive diseases), an oncologist (cancer specialist), a surgeon, or a radiation oncologist (specialises in radiation cancer treatment).

Your doctor will likely ask you a series of questions, like if you’ve noticed any symptoms, when you first started noticing them, or if you have any family history of the disease.

What to expect

Your doctor or a specialist will then perform tests in order to provide a diagnosis. These tests typically include colonoscopy or CT colonoscopy. In a colonoscopy test, the doctor will view the insides of your colon and rectum using a long slender tube with a video camera. The doctor may then take a tissue sample if there is anything suspicious in the area. CT colonoscopy, on the other hand, makes use of virtual images and is mostly recommended for people who are unable to undergo a regular colonoscopy.

Colon Cancer Stages

If your doctor confirms that you do in fact have colon cancer, the first course of action is to determine the stage of cancer.

  • Stage I colon cancer refers to cancers that have not spread.

  • Stage II is when cancer has penetrated through the colon or rectum wall but has not spread to the lymph nodes.

  • Stage III is when cancer has infected the lymph nodes but has not spread to other body parts.

  • Stage IV is when cancer has already spread to other organs.


Once your doctor has determined the stage of cancer, the next step is to create a treatment plan. If cancer is still in its early stages (stage I) there is a chance that it can be removed during a colonoscopy. If not, the doctor will recommend a laparoscopic surgery procedure.

If cancer has reached stage II, the doctor will likely recommend a partial colectomy, a procedure that involves removing the part of your colon that has cancer.

If the cancer is determined to be in the advanced stages, or has already blocked your colon, the surgery will be performed to remove the blockage, but only to reduce the symptoms. To treat cancer, the doctor will recommend chemotherapy, radiation therapy, or targeted drug therapy. It is important to understand that none of the treatment methods for advanced stage colon cancer comes with a guarantee. Each has advantages, disadvantages, and risks that you should be aware of before deciding to undergo any treatment.


Since the exact causes of colon cancer are not yet been discovered, there is no way to prevent it. However, you can reduce the risks of having this type of cancer by applying simple lifestyle changes. These include:

  • Consume more fruits, whole grains, and vegetables

  • Avoid or decrease alcohol consumption

  • Quit smoking

  • Exercise on a regular basis

  • Maintain and ideal weight

It has been thought that cancer is also a result of high levels of toxins in the body. Thus, antioxidants can play an important role in preventing the occurrence of cancer, whether originating in the colon or any other part of the body.


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