Bowel cancer is a general term for describing cancer that develops in the large intestine. Based on the location where cancer begins in the bowel, it is sometimes referred to as colon or rectal cancer.
About 1.8 million new cases of bowel cancer were reported in the year 2018 globally
Bowel cancer occurs when the cells lining the colon or the rectum begin to grow and divide uncontrollably without dying. This results in the formation of a mass of tissue, known as a polyp. Developing polyps does not always mean you have cancer, but if these polyps grow and divide continuously, they become cancerous.
Additionally, there are several factors which increase the risk of bowel cancer. These include:
- Age more than 50 years
- Family history
- Medical conditions, such as diabetes and heart diseases
- A diet rich in processed meat
- Physical inactivity
The signs and symptoms of colon cancer include the following:
- Change in bowel habit
- Blood in stools
- Abdominal pain
- Anal or rectal pain
- Unintentional weight loss
Symptoms during the progression of Colon cancer
When colon cancer has spread to other parts of the body, such as the liver, lungs, or bones, then the person may experience the following symptoms:
- Loss of appetite
- Swelling in the legs
- Severe cough
- Difficulty in breathing
- Bone pain
- Numbness or weakness in legs
- Back pain
Additionally, the patient may also experience symptoms related to the organs where cancer has reached.
Diagnosing bowel cancer during the early stages help in providing appropriate treatment. The doctor begins the diagnosis by doing a clinical assessment, wherein the patient’s medical history, medication history, and the signs and symptoms are recorded. A physical examination is done to feel the abdomen and other parts of the body to detect any enlarged organs or abnormal masses. If any abnormal masses are found, then a digital rectal examination may be recommended.
- Digital rectal examination (DRE): A DRE is performed by inserting a lubricated, gloved finger in the rectum to determine the presence of any lumps in the abdomen.
- Faecal immunochemical test (FIT): A sample of stool is collected to detect the presence of hidden blood in the stools, which might be a sign of bowel cancer.
- Stool DNA test: A stool sample is collected and examined to check for blood in the stool as well as DNA of the blood cells, which may come from the shredded cells of the colon and rectal cell lining. If any DNA abnormalities are noticed, then a colonoscopy is recommended.
- Colonoscopy: In this test, a colonoscope (a thin, long, tube-like instrument with a light, an outlet for air, and camera) is lubricated and inserted into the rectum and passed till the starting point of the colon (cecum). The camera present at the end of the colonoscope transmits the images of the colon lining to an external monitor. If any abnormalities are noticed, then a sample of tissue may be collected and examined in the laboratory.
- CT colonography: This test involves scanning the rectum and colon using a CT scan. It is the best alternative for patients who are not eligible for a colonoscopy.
Once the cancer is diagnosed, certain imaging tests, such as an ultrasound or MRI scans, are done to determine the extent of cancer.
The staging of bowel cancer is as follows:
- Stage 0: The cancer is present only in the inner layer of the bowel.
- Stage-1: Cancer has spread to the muscle layer of the bowel wall, but has not spread to the lymph nodes.
- Stage-2: Cancer has spread to the outer layer of the bowel wall and has invaded the surrounding tissue, but has not spread to the lymph nodes.
- Stage-3: Cancer has spread to lymph nodes, but has not reached to other parts of the body.
- Stage 4: Cancer has spread to all the surrounding lymph nodes and other parts of the body, such as the liver or lungs.
- The following are the common complications of bowel cancer surgery:
- Wound infection
- Bleeding at the incision site
- Blood clots in the legs
- Pain and swelling in the abdomen
The following activities help the patient in quicker recovery:
- Do not lift heavy-weights
- Take the prescribed medicines
- Keep the incision site clean and dry
- Do not strain for a bowel movement
- Drink plenty of water
Duration of treatment
After surgical removal of cancer, the doctor will initiate chemotherapy. Chemotherapy is given for at least six months. For an effective result, chemotherapy and radiation therapy are combined. Radiation therapy is given for five days a week for about five to six weeks.
Depending on the location, size, and stage of cancer, bowel cancer can be treated with the following:
Surgery: It is the most common treatment option for bowel cancer. Surgery is usually performed based on the location of cancer, whether it is present in the colon or rectum.
Surgery for colon cancer:
If cancer has spread to the nearby tissues, then all the affected parts of the colon should be removed surgically. The procedure, which involves removal of all the parts of the colon, is referred to as colectomy. Colectomy can be performed in the following ways:
- Open colectomy: General anaesthesia is administered, and a long incision is made on the abdomen to access the colon. Based on the extent of the tumour, either a single section of colon (partial colectomy) or complete colon (total colectomy) is removed.
- Laparoscopic colectomy: In this procedure, several small incisions are made on the patient’s abdomen. Now, special surgical instruments guided with a tiny video camera are passed through the incision to remove the damaged section of the colon.
- Robotic colectomy: It is a minimally invasive procedure in which the surgeon instructs and handles the robot to detect and remove the cancer cells.
- Colostomy: A piece of the colon is cut and brought on to the surface of the body (abdomen area) that allows stool and gas to pass out of the body without passing through the rectum. The opening on the abdomen, which is connected to the colon to pass the waste material outside is called as ‘stoma’.
Sometimes, instead of colon, the surgeon may cut an end of the small intestine and connect it to an opening made in the skin of the abdomen. This procedure is called ileostomy.
Surgery for rectal cancer:
The following are the surgical options for treating cancer in the rectum:
- Local resection: In this procedure, all the layers of rectal walls are cut to remove cancer and also the surrounding healthy tissues.
- Total mesenteric excision: A large area of the rectum can be removed through this surgery. Depending on the region where cancer is located in the rectum, either of the following surgeries can be performed:
- Anterior resection: In this procedure, an incision is made on the abdomen to remove the part of the rectum that has tumours.
- Abdominoperineal resection: Several small incisions are made on the abdomen, and a single incision is made around the anus to remove the rectum, anus, and the surrounding tissues.
- Pelvic exenteration: It is performed when the rectal cancer is growing into the surrounding organs. In this procedure, the rectum, along with the nearby organs where cancer has reached, are removed.
Chemotherapy: It involves the usage of medicines or chemicals to kill cancer cells.
Radiation therapy: High-beam rays are delivered to destroy the cancer cells without causing much harm to the surrounding healthy tissues.
Targeted therapy: This therapy inhibits the action of specific proteins that are responsible for the growth and progression of cancer cells.
FACTORS AFFECTING COST
The cost of bowel cancer treatment is 30 to 50% less in India when compared with other countries. The cost of bowel cancer depends on several factors, such as:
- Type of hospital
- The stage of cancer
- Type of treatment
- Doctor’s fee
- Hospital stay
- Current medication cost
- Follow-up visits