Colon is a 6 feet long tube-like organ, a very Vital part of the digestive tract that connects the small intestine to the rectum. Colon and rectum together comprise the large intestine, Which is primarily meant for the storage and managing the waste products generated by the body. It also helps in the absorption of the water from the food.
A colon cancer begins in the colon or rectum is termed. It is also known as rectal cancer or colorectal cancer. Most colon cancers are adenocarcinomas which start when a mutation takes place in the lining of the wall of the colon or rectum. Cancer usually begins with the formation of polyps often called adenoma in the intestine. Polyps are the abnormal growth of tissue that becomes precancerous initially and then becomes cancerous.
There are many potential symptoms of colon cancer, and what symptoms a person experience depends on factors like the location and size of cancer.
In the early stages of colon cancer, some people experience no symptoms. In addition, the signs and symptoms mentioned below may be (and usually are) due to a non-cancerous medical condition, like an infection or haemorrhoids.
Colon cancer symptoms include:
- A change in bowel habits, like experiencing diarrhoea, constipation, or stool thinning (“pencil stools”) that lasts for more than a few days
- Alternating constipation and diarrhoea, potentially due to a partial obstruction of a tumor in the colon
- Bright red or dark red blood in your stools can be seen
- Feeling like you cannot completely empty your bowels
- Abdominal discomfort and cramping
- Whole-body symptoms like weakness, unusual tiredness, unintended weight loss, and a loss of appetite of the person
- Nausea or vomiting
- Yellowing of the skin or whites of the eyes (called jaundice) of the person
How is colon cancer diagnosed?
Early diagnosis of colorectal or colon cancer gives you the best chance of curing it.
Your doctor will start by getting information about patient’s medical and family history. They’ll also perform a physical exam. Doctor may press on patient’s abdomen or perform a rectal exam to determine the presence of lumps or polyps.
- Blood testing: Some blood tests can be done to get a better idea of what’s causing your symptoms. In medical science, there’s no blood test that specifically checks for colorectal cancer, liver function tests and complete blood count tests can rule out other diseases and disorders.
- Colonoscopy: This procedure involves the use of a long tube with a small, attached camera. This procedure allows your doctor to see inside your colon and rectum to check for anything unusual inside. During this procedure, your doctor can also remove tissue from abnormal areas. Then later these tissues can be sent to a laboratory for analysis.
- X-ray: During this procedure your doctor may order an X-ray using a radioactive contrast solution that contains the metallic element barium. Your doctor will insert this liquid into your bowels through the use of an enema tube, once in place, the barium solution coats the lining of the colon. This helps improve the quality of the X-ray images.
- CT scan: CT scans is used by doctor to get detailed image of your colon. During diagnosing colorectal cancer, another name for a CT scan is a virtual colonoscopy.
Stages of colon cancer:
For preventing further spread of the disease and plan the appropriate treatment plan to cure cancer, breaking into staging the cancer is important. The colon cancer can be staged as;
- Stage I: In this stage cancer has normally begun but confined to the inner wall lining of the colon.
- Stage II: In this stage cancer has spread to the organs adjacent to the colon or rectum but has not invaded the lymph nodes.
- Stage III: In this stage cancer has invaded the lymph nodes but has not spread to distant organs of the body
- Stage IV: In this stage cancer has spread to lymph nodes and is carried to distant organs through the lymphatic system. The common organs to get affected first are Lungs and liver.
Cause of Colon cancer:
It is difficult to pinpoint the exact cause of Colon cancer. But the factors that increase the risk of developing colon cancer are;
- Advancing age.
- Race: African and American have a greater possibility of colon cancer
- History of adenomatous polyps
- Inflammation of the intestine as in ulcerative colitis, Crohn’s disease
- Genetic inheritance
- Any family history of colon cancer or polyps
- Dietary habits that include intake of low fibre and high-fat diet.
- Sedentary lifestyle
- Smoking, alcoholism, diabetes
- Overweight and obesity
- Exposure to radiation therapy
Surgery aims at removing the colon or rectum or a part of it affected by cancer, with or without the adjacent lymph nodes using one of the following approaches. The type of surgery needs to be performed depends on the type, size, location and the extent of the cancer spread.
- Polypectomy: Polypectomy involves removal of the polyps which are small adenomatous growth that is present in the inner lining of the wall of the colon. They are removed using colonoscopy.
- Colectomy: Colectomy involves removing the part or whole of the colon with cancer and some of the surrounding tissue. This can be done in two ways:
- Traditional open colectomy: involves removal of the part or whole of the colon through a single large incision in the abdomen.
- Laparoscopic colectomy: this procedure commonly used, in this colectomy is done through multiple small incisions of about 5-10mm size using laparoscope and specialized laparoscopic surgical instruments.
- Chemotherapy: This therapy involves giving medicines either intravenously or orally to attack and kill the cancerous cells. It can be used before the surgery in order to shrink the size of the tumour or after the surgery to eliminate the cancer cells if left any inside. Chemotherapy is also given to slow down advancing cancer and to relieve the symptoms in case of extensive cancer.
- Radiation therapy: Involves delivery of high powered energy beam like protons or X-rays to specifically target cancer cells without or minimally affecting the normal healthy cells of the body. It can be used in combination with chemotherapy either before or after the surgery or may be used for relieving the symptoms associated with cancer if the cancer is extensive and cure is not possible.