Colorectum Cancer
What is Colorectum Cancer?
The large intestine is made up of the colon and rectum. The rectum comprises the last 15cm of the large intestine and lies within the pelvis which is made up of the hip bones. This is a very small area and the distance between the cancer and the surrounding normal organs is very short. Hence, the chance of the cancer spreading to neighbouring organs in the pelvis is significant.
The colon forms the rest of the large intestine which lies above the level of the hips. It is surrounded by fatty tissue, called omentum, and anchored by more fatty tissue, called mesentery, to the walls of the abdominal cavity. In the mesentery are the lymph glands.
Cancer can develop from the cells lining the large intestine. The cancer can cause blockage of the intestine, or bleeding into faeces.
How common is Colorectum Cancer?
Colorectum cancer is now the commonest cancer in Singapore. It affects males and females alike. Between 1993 and 1997, about 4899 cases were diagnosed in Singapore.
Age of Onset
Most persons diagnosed with Colorectum cancer are older than 45 years of age. Younger persons, less than 20 years of age, diagnosed to have Colorectum cancer must be suspected to have a hereditary form of Colorectum cancer, such as familial adenomatous polyposis.
Risks and Causes
Much has been discussed regarding the role of dietary factors and Colorectum cancer. There are suggestions that dietary intake.
Persons considered to be at high risk of Colorectum cancers are persons with a history of Colorectum polyps, previous Colorectum cancer, persons with one immediate relative diagnosed to have Colorectum cancer before the age of 45 years, persons with two or three immediate relatives diagnosed with Colorectum cancer at any age, or persons with a family known to have familial adenomatous polyposis.
Symptoms and Signs of Colorectum Cancer
Common symptoms persons have are a change in bowel habits, such as persistent diarrhoea or constipation or a change in the frequency of stools. Passing blood mixed with stools is also suspicious sign which always needs prompt medical attention.
Other symptoms include persistent ill-defined abdominal discomfort or pain. Occasionally a mass is felt in the abdomen.
Diagnostic Tests
The simplest way to detect a rectal cancer is by insertion of the doctor's finger into the rectum, i.e. a rectal examination. This can be done in the outpatient clinic, takes less than 5 minutes and causes minimal discomfort. However, this detects cancers only in the last 5 to 8 cm of the rectum.
For cancers which are more distantly located in the large intestine, sigmoidoscope or colonoscope examination can be performed. These fiber-optic flexible tubes are inserted up the rectum into the colon. Through these scopes, removal of a small piece of growth for testing is possible. Insertion of these scopes are performed with minimal anaesthesia in an outpatient clinic. Although uncomfortable, the procedure lasts less than 30 minutes.
An x-ray examination called a barium enema may also be performed to examine the whole length of the large intestine. A dye is inserted into the rectum and allowed to coat the length of the intestine. Multiple x-ray films are subsequently taken of various portions of the large intestine and abnormal areas identified. A suspicious area must then be biopsied using a colonoscope or sigmoidoscope.
Physical examination by the doctor of the neck, chest and abdomen are important as Colorectum cancers can spread to lymph glands in the neck, to the lung and to the liver. Blood tests may also be helpful in certain circumstances.
Once cancer is confirmed, x-rays of the lungs and scans of the liver are required before further treatment is advised.
Treatment of Colon Cancer
The mainstay of treatment is surgery. The cancer, its surrounding fat and lymph glands are removed in one piece. The two ends of the cut section are joined together. During surgery, the surgeon will normally inspect the liver and other surrounding organs for signs of cancer as well.
Depending on the stage of the cancer, chemotherapy may be required after surgery to improve a person's chance of cure from cancer. Chemotherapy involves injections of cancer killing medicines into a vein on the hand. Chemotherapy, which lasts from 6 to 12 months, is usually associated with mild mouth ulcers, mild diarrhoea, mild hair loss, possible darkening of complexion, and nausea. The commonest medicine used is 5- fluorouracil, though other drugs may be used in addition.
Treatment of Rectal Cancer
Again, the mainstay of treatment is surgery. Because of the position of the rectum in the bony pelvis, the chance of cancer spreading to the surrounding organs, such as bladder, uterus and bone, is high. Even if the cancer was totally removed by surgery, occasionally there is concern that undetectable cancer cells may lie in the vicinity since the distance between cancer and normal tissue is so short. Hence, depending on how far the cancer has invaded surrounding fat and organs, and other factors, radiotherapy may be required after surgery to improve a person's chance of remaining free from rectal cancer.
Radiotherapy involves giving high-energy rays into a small area where the original cancer was. The course of treatment, given daily for 5 minutes, usually lasts 5 to 6 weeks. Side effects which may occur include diarrhoea, tiredness, skin redness and rash. In some women, radiotherapy brings on early menopause.
As with colon cancer, chemotherapy may also be required, after surgery. Radiotherapy may be given together with chemotherapy.
Why do i need a Stoma?
A stoma is an opening in the abdominal wall. The inner end of the stoma is the large intestine and the stoma opens onto the skin of the abdomen. Occasionally the stoma is temporary to allow more time for the large intestine to recover from recent surgery. Occasionally the stoma is permanent. This happens because the rectal cancer has occurred very low down in the rectum and, after removal of the cancer, insufficient normal rectum is left to join back to normal intestine.
There are Stoma nurses who will counsel persons who require a stoma after surgery. Your surgeon will refer you to the nurse any time a stoma is created. The Singapore Cancer Society also has a Stoma Club which caters to any patient with permanent stomas. With the help of volunteer surgeons, stoma-care nurses and others, persons with stomas are given help on how to take care of their stoma, diets, types of stoma bags, clothing and psychological support to lead a normal life.
Prognosis of Colorectum Cancer
Prognosis means the probable outcome of an illness based upon all the relevant facts of the case. All findings from clinical examination and x-ray investigations and pathology reports are important and must be considered together to decide what the progress of an individual case of Colorectum cancer may be. From this, the appropriate course of treatment can be decided and put into action. The treatment strategy will vary from person to person. With prompt and appropriate treatment, the outlook for a person with early Colorectum cancer is good.
The doctor looks for the following features:
- The site of the large intestine cancer is important. This will determine what type of surgery is required and whether a stoma is likely to be created. This will also determine if radiotherapy is required after surgery.
- How many of the lymph glands in the mesentery were involved? The more lymph glands involved, the more likely the cancer will recur. When lymph glands are involved, chemotherapy is usually recommended to improve a person's chance of cure.
- Did the cancer involve other organs? In the presence of advanced disease, chemotherapy and occasionally radiotherapy improves a person's quality of life, prolonging the time to further growth of the cancer and overall survival. New drugs are being developed every few years. Some of these drugs may already be available in a clinical study being run at your centre. Ask your doctor for more information.
Frequently Asked Questions about Colorectum Cancer
1. I have haemorrhoids. Will these become cancerous?
Haemorrhoids are enlarged blood vessels of the rectum. They arise because of constipation or pregnancy. They do not become cancerous. However, they will bleed from time to time and over the years may cause anaemia or a lack of red blood cells which may cause symptoms such as tiredness and breathlessness. Haemorrhoids which are bleeding, itching or discharging mucus, should be attended to by a professional. Any bleeding from the back passage requires investigation and should not be assumed to be hemorrhoidal in origin.
2. My father / uncle was diagnosed to have large intestinal cancer?
Am I at higher risk?
Persons considered to be at high risk of Colorectum cancers are persons with a history of Colorectum polyps, previous Colorectum cancer, persons with one immediate relative diagnosed to have Colorectum cancer before the age of 45 years, persons with two or three immediate relatives diagnosed with colorectum cancer at any age, persons with a family member known to have familial adenomatous polyposis.
Any patient with familial adenomatous polyposis is usually informed by his surgeon to send the rest of his family for screening. This is a hereditary condition where hundreds and thousands of polyps develop in the colon, rectum and occasionally stomach. It is usually present by the teenage years. The risk of developing Colorectum cancer from one of these polyps is very high. Very often, the affected person has his colon removed before development of colon cancer. He or she can still lead a normal life after surgery. The diagnosis of familial adenomatous polyposis is usually made on sigmoidoscopy or colonoscopy. Recently, a blood test has been developed that can detect the abnormal gene responsible for this condition.
Persons considered to be at high risk for developing Colorectum cancer should consider colonoscopy every 3 years. Persons with a history of colonic polyp should consider colonoscopy and removal of polyps every year until no new polyps develop. Thereafter colonoscopy should be performed every 3 years.
3. I am afraid of Colorectum cancer. Should I go for screening?
If you are worried about Colorectum cancer, you can discuss the possibility of faecal occult blood testing with the general practitional. The most effective screening test is colonoscopy , which is recommended in some countries for routine screening of individuals aged 50- 70 every 3 years.
4. I have been diagnosed to have Colorectum cancer. How long will I live?
Many people who have had Colorectum cancer live a normal lifespan. Present treatments offer a good prognosis but you may require several types of treatment to have the best chance of avoiding recurrence of the cancer.
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