What is colon cancer?

Colon cancer is a type of cancerous growth that affects the area of your large intestine, or colon. The colon is the last section of your digestive tract. This type of cancer usually affects aged individuals, though this is not always true. Colon cancer is also a part of the term, “colorectal cancer” which also includes cancer of the rectum or the last part of the digestive tract.

How does it start?

Colon cancer starts usually from the transformation of small finger-like outgrowths on the inside part of your intestine called polyps. Polyps themselves are non-cancerous. But, they have a high chance of converting into cancerous growths and colon cancer later on.

What are the early symptoms?

Usually, colon cancer starts with no symptoms in the earliest stages. As the situation becomes worse, the symptoms start showing. Some of the common early-stage symptoms are:

• Blood when you pass stools
• Diarrhoea, Constipation or Narrow Ribbon stools
• An unsatisfactory feeling after emptying stools
• Pain, cramping and bloating in the stomach
• The feeling of wanting to vomit or vomiting
• Lack of hunger
• Anaemia
• General weakness
• Sudden weight-loss

The most dangerous symptom which should draw attention immediately is the presence of blood in your stools. But, this may not always mean you have colon cancer. It is important not to jump to conclusions and consult your doctor. Other problems like haemorrhoids, tears, ulcerative colitis, Crohn’s disease etc. may also have a similar presentation.

Anaemia is also a symptom to watch out for. You will usually feel tired and short of breath and it becomes hard to recover even after resting.

What are the factors that can increase your risk of developing colon cancer?

• Older age (>50 years)
• Being part of a race with a predisposition like African Americans
• Family history including related conditions like familial adenomatous polyposis (FAP) and Lynch syndrome
• Personal history of polyps
• Chronic inflammatory conditions like Crohn’s disease or ulcerative colitis
• Low-fiber, high-fat diet
• Lack of exercise and movement in daily life
• Diabetes
• Obesity
• Smoking
• Alcohol
• Radiation therapy for cancer

How can I prevent it from occurring?

Although there is no sure way to prevent it, it is possible to catch the disease early when it is easier to treat through screening tests. If you believe you are at risk or have any of the symptoms, it is a good idea to check with your doctor on how you can get screened for colorectal cancer. Another good approach is to stay away from risky habits like smoking and drinking and to keep your weight and sugar levels under check.

How is it diagnosed?

There are several screening procedures available like Fecal immunochemical test (FIT), Guaiac-based fecal occult blood test (gFOBT), Fecal DNA test, Flexible sigmoidoscopy, Colonoscopy, Double-contrast barium enema, CT colonography (virtual colonoscopy). However, each procedure has its strengths and weaknesses. Your doctor will combine multiple methods to ensure that you have the right diagnosis and ensure you do not have to go through difficulty unnecessarily. Your doctor will ask you for:

• Blood tests (Complete blood count, tumour markers and liver enzymes)
• Imaging tests (X-rays, CT scan, MRI scan, PET scan, ultrasound, angiography)
• Biopsy
• Diagnostic colonoscopy (only after you show symptoms)
• Proctoscopy
• Routine screening tests

How is colon cancer treated?

The treatment of colon cancer depends on the progress of cancer, which is denoted by a Stage based classification system. However, please be advised that the right treatment for you depends on many factors and your doctor is the best person to help you with this:

• Stage 0: the disease remains within the lining of the intestine. They are not cancers. So, removal by polypectomy via colonoscopy or by surgery its too large may be all that is required for treatment.

• Stage I: They have grown into the wall of the intestine but have not spread beyond its muscle layer or to nearby lymph nodes. The treatment is usually colon resection, in which the affected part of the colon and its lymph nodes are removed.

• Stage II:
  • IIA, cancer has spread through the wall of the colon
  • IIB, colorectal cancer has penetrated beyond the muscular layers of the large intestine
  • IIC, cancer has even spread into adjacent tissue.

In stage II, cancer has not yet reached the lymph nodes. For stage II cancer, surgical resection is usually followed by chemotherapy and/or other methods.

• Stage III: an advanced stage of cancer as the disease has spread to the lymph nodes, again divided into 3 sub-stages. For colon cancer, surgery is usually done first to lower the tumour load, followed by chemotherapy.

• Stage IV: cancer has spread to other organs such as the liver, lungs or ovaries. Surgery is generally used for relieving or preventing complications rather than treating the condition itself. Stage IV cancer that cannot be removed by surgery, chemotherapy, radiation therapy, or both may be used to relieve, delay, or prevent symptoms.