Colorectal Cancer

Colorectal cancer is cancer of the colon and the rectum. The colon and the rectum form the lower part of the digestive system, where the large intestine is located. After food gets into the stomach, it passes through the small intestine into the colon. The colon functions by absorbing nutrients and water from the food and passing waste into the rectum before it leaves the body.

Colon cancer starts in the form of noncancerous polyps that form into clumps of abnormal cells within the inner lining of the colon. Later, the polyps become cancerous. Regular screening and testing of your colon and rectum will help keep the disease at bay.

The actual cause of colon cancer is still unknown. Oncologists are only aware of the fact that the cancer arises when the DNA of cells suddenly starts to act abnormally. When these disrupted or abnormal cells form into a mass, they turn into malignant tumours.

Doctors, however, suggest that the reasons of colorectal cancer are directly linked to inherited genes, familial adenomatous polyposis (FAP) that causes thousands of colon to develop and heredity nonpolyposis colorectal cancer (increases risk of colon cancer in individuals over 50 years).  Other reasons include inflammatory intestinal conditions, individuals of African-American race, family history of colon cancer, high-fat and low-fibre diet, a sedentary lifestyle, diabetes, smoking, alcohol and obesity.

If you notice any of these signs, you should refer to a doctor immediately. Symptoms of colon cancer are:

• Unexplained weight loss
• Change in consistency of stool, changes in bowel habits (constipation or diarrhoea)
• Blood in stool
• Gas, pain and cramps in the stomach and abdomen
• Weakness or fatigue
• Feeling of bowel is full all the time

Diagnosis of colorectal cancer is done by conducting several tests and procedures. A type of long, flexible tube (called Colonoscope) is inserted through the rectum to take pictures of the inside of the rectum and colon for any suspicious areas. This procedure of testing is called Colonoscopy that allows doctors to collect tissue sample from the colon tumours for a biopsy test.

Although, blood tests don’t reveal whether you have the cancer or not, but specific clues like your liver function and kidney function, level of chemical substances in your blood produced by colon cancer help doctors evaluate your health and understand your prognosis.

Remember, the initial stage of colorectal cancer shows no signs of the disease, but those who are at higher risk of getting the cancer should undergo screening tests beginning at the age of 50. Stage I and stage II colorectal cancer is confined within the walls of the colon and therectum, while stage III and stage IV cancer have spread to nearby lymph nodes and other organs of the body.

Treatment options for colorectal cancer depend upon the stage of the disease. Early stage of colon cancer is treated with:

• Colonoscopy for removing polyp growth inside the colon and the rectal lining
• Endoscopy mucosal resection for removing larger polyps
• Minimally invasive surgery to get access to the polyps that are, otherwise, hard to reach with colonoscopy. The procedure makes small incision in the abdomen.

A tube is inserted through it that has a camera fitted to its one end, while other surgical instruments are placed through the cuts to remove the polyps while looking at the visual images of the patient’s colon and rectum on a computer screen.

When colon cancer has spread through the entire colon, it is treated with:

• Partial colectomy that involves the removal of a part of your colon that contains the disease and also a margin of abnormal tissues from both sides of the diseased parts.

In open colectomy, doctors make a large incision in the abdomen for removing the cancerous parts, affected lymph nodes and tissues. The lower part of the intestine is then connected to the rectum. Sometimes, surgeons create a stoma to connect the lower part of the intestine to the outside of the skin to allow waste pass out of the body.

Advanced stage of colorectal cancer is treated with surgery, chemotherapy, radiation therapy, targeted therapy or a combination of the procedures.

This is how you prepare before colorectal cancer surgery:

• A week before the surgery, get a thorough physical examination to evaluate your health condition and whether you are prepared for the surgery.
• Talk to an oncologist regarding the type of procedure you will go through, the benefits of the procedure, any side effects and the overall outcome.
• Tell your doctor about your physical and mental health conditions and the medications you are on. Your medical history will help the doctor assess your condition and advice you to stop any medications you are already having or prescribe new medicines before the surgery.
• Most patients receive anticoagulation therapy to reduce possibilities of blood clotting.
• Do not eat or drink anything after the night before the surgery.
• Take some preoperative bowel preparations like having laxatives to empty your stomach before the surgery.

There are several types of procedures performed to treat colorectal cancer. Read to know how colorectal cancer surgery is performed:

• Surgery - An early stage of colorectal cancer is treated with local excision in which the doctor inserts a colonoscope through the rectum, while you are awake. You lie down on your side with the knees drawn up to your chest. Your doctors insert a tube with a camera fitted to it to help view the inside if the colon while removing the polyps with other surgical instruments inserted through the same tube. Surgeons may also use minimally invasive procedure (laparoscopic colectomy) to remove polyps. During the procedure, local anaesthesia is given to the patient to numb the abdomen area. A small incision is done in the lower abdomen and surgical instruments are inserted with an attached camera to it to perform the surgery while viewing the colon on a screen. Sample tissues taken from the colon tumours are examined to evaluate the condition. Open colectomy is a surgery performed when your cancer has spread to other body parts. A long incision is performed in the abdomen to help surgeons get direct access to the colon. Before the surgery, anaesthesia helps the patient to sleep through the procedure. The cancerous portion of the colon and rectum are removed after which a stoma is created by attaching the lower part of the intestine up to an opening in the skin for passage of waste out of the body. 

• Radiation Therapy or chemotherapy - Radiation therapy is used when cancer has spread through the walls of the rectum into the nearby lymph nodes. Sometimes, radiation therapy is used in conjunction with chemotherapy to reduce the chance of cancer. During the procedure, the patient has to lie still, while radiation beams are directed on the parts of the body where the colon cancer has spread.Chemotherapy allows doctors treat cancerous cells and diseased lymph nodes located away from the main site of colon cancer. The therapy is given in the form of oral pills or through injection to help the medicine reach the bloodstream and kill cancer cells in areas where radiation or surgery cannot reach.

Immediately after the surgery, you are transferred to the recovery room. You are given a breathing mask that will help eliminate the effects of anaesthesia and soothe your throat. The doctors and nurses will constantly monitor you to check if you are recovering or are there any complications. You are given only liquids in the first couple of days and then switched to foods as you recover.

The recovery of colorectal cancer surgery depends upon the type of surgery you went through. The average hospital stays vary from 3 to 6 days for laparoscopic surgery, while this duration is longer for an open surgery. Since the motion of food moving through the intestine changes after a colorectal surgery, you need to be careful about what you eat. It is advised to rely on a soft diet, and avoid vegetables and raw fruits.