Low dose (80 mg) aspirin has been reported to reduce the chance of recurrent adenomas of the large intestine after pre-existing polyps have been removed by 19% In patients with advanced adenomas or colorectal cancer, the risk of adenoma or cancer recurrence was also reduced by 40%. However a higher dose is not more protective but actually had a lesser effect, reducing adenoma recurrence overall by 4% and advanced adenoma and colorectal cancer recurrence by 19% only.

Many studies have shown that non-steroidal anti-inflammatory drugs (NSAID) such as aspirin and others can reduce the size and number of polyps in patients with familial adenomatous polyposis. These drugs however cause a lot of gastric upset and ulceration. More recently a new class of NSAID known as COX-2 inhibitors have been tested and preliminary results were said to be efficacious without the gastric side effects. These drugs are currently undergoing further testing.

The most useful and fail safe method currently of preventing colorectal cancer however, is colonoscopy and removal of all pre-malignant polyps present. Regular exercise is important in maintaining a healthy Removal of a large polyp lifestyle and may help in the prevention of colorectal cancer. Brisk activity three to five times a week including walking, cycling, swimming, aerobic exercises or jogging will certainly help maintain general good health and boosts the body's immune defense against infection and cancer. Certain environmental factors including diet high in fat, excessive caloric and alcohol intake, obesity, sedentary life style and smoking have an association with increased risk of colorectal cancer and a change in lifestyle may be of some value in preventing colorectal cancer.

People with high risks of colorectal cancer includes those with:

1. a strong family history of large bowel cancer or other related cancers in first degree relatives.
2. a previous history of adenomas or cancer of the large bowel.
3. a history of chronic ulcerative colitis or Crohn's disease.

One of the most important factors in the pathogenesis of large bowel cancers may be inherited susceptibility for colorectal cancer. First degree relatives of patients with colorectal cancer have therefore increased risk of about 3-4 times for development of colorectal cancer compared to the average person in the street. Patients with a previous colorectal cancer have also a 3-4 times increased risk of developing a second large bowel cancer and therefore life long surveillance in these patients is essential.

Patients with adenomas and especially those with familial adenomatous polyposis (a genetic condition where hundreds or thousands of adenomas may be present), are at increased risk of cancer formation unless polyps are removed totally. Patients with ulcerative colitis and Crohn's disease have increased risk for developing large bowel cancer especially if the disease has been present for more than 10 years.

The colorectum is a hollow muscular tube concerned with allowing digested food and waste to pass through. Symptoms therefore only arise when this smooth passage is disturbed, and because of the elasticity and huge reserve of the large intestine, symptoms are often minimal or occur only late in the disease. Hence, 60% of colorectal cancer patients presenting to hospitals already have lymph node spread or widespread cancer. Symptoms depend on the stage of the disease as well as the location of the cancer In the colorectum. During the early stages of cancer most patients do not have symptoms. The commonest symptom of large bowel cancer is rectal bleeding which occurs in both benign adenomas and cancers. Often however this can only be detected in very minute amounts and cannot be seen with the naked eyes.

As a summary the following may be useful:

1. Blood in the stools.
2. A change from your normal bowel habit usually with looser stools with no immediately obvious reason.
3. Unexplained loss of weight.
4. Recent onset of abdominal colic.
5. A persistent feeling of still having stools in spite of last having had a bowel motion.

Generally the hospital doctor will take a detailed account of your medical problems as well as making you relate your past and family history. The doctor will then do a physical examination that must include a rectal examination and a proctoscopy. You may then be asked to do a faecal occult blood test, a blood test as well as be booked for colonoscopy or a barium enema test. If cancer is already confirmed, liver ultrasound or CAT scan may be needed.

The carcino-embryonic antigen (CEA) is a protein that is easily measured with an inexpensive and simple test. CEA is normally found in low concentrations in embryonic and fetal gut as well as in pancreatic, lung and liver cells. Hence mild elevations may be found in pregnancy, as well as in smokers and in inflammatory and as well as malignant conditions of the respiratory, hepato-biliary and gastrointestinal system.

This test is not done for screening, as it is only helpful after a diagnosis of colorectal cancer is made. However, a raised CEA in a "normal" person must be an indication that the colorectum needs to be investigated further.

1. Barium enema
   This is a special x-ray procedure where dye (barium sulfate) and air is pumped through the anus to visualize the large bowel. Although it is not as accurate as colonoscopy, it can pick up most large polyps and cancers and is several times cheaper than a colonoscopy. One disadvantage is the inability for simultaneous excision of polyps as biopsy is not possible. For a few days following the test your stools may be whitish but there is nothing to be concerned about as it is only the barium which is being passed out.
2. Colonoscopy
   This is the gold standard for detection of colonic lesions. For this test to be successful, the large bowel has to be meticulously cleaned before the procedure. Most modern laxatives work with the ingestion of two or three liters of plain water and should produce about 2 to 6 loose watery diarrhoea starting within an hour after ingestion of the laxative. A sedative may be given but most patients undergoing colonoscopy have very mild tolerable discomfort and do not require sedatives. In any case the unsedated patient may be guided through the procedure and any lesions found may be pointed out to you and may help you to understand your situation better. The lack of availability of colonoscopy for everyone; the expense and the small risks involved should not mitigate against those who would prefer a total colonoscopy as a screening test for the detection of colorectal cancer and its precursor polyps. Thus people who have the means and the resources and who understand the risks involved should certainly be allowed to avail themselves to this method of investigation.
3. New imaging modalities
   New modalities like capsule colonoscopy, virtual colonoscopy a colonoscopy are being investigated and may be offered by limited new centers on an experimental basis. Virtual colonoscopy is a diagnosis on and the presence of polyps, meaning that a real colonoscopy will have performed to remove the said lesion.

It is important that a proper family history of cancer be taken. Especially families where there are a large number of members with colorectal cancer and other families that have a large number of colorectal cancer together with other cancers especially of the urinary system and female genital tract. These two sort of families usually have several members who had the disease when they were very young, less than 40 years of age. Special consideration must be given to the surveillance of members of these two sorts of families for screening at younger ages, than would be applicable to the general population. Special families with high risk for colorectal cancer are families with HNPCC and FAP.

However if the index or first case is the only one with colorectal cancer in the family and this person is older than 50 years of age then the other members of this particular family have only the low population-at-large risk of getting colorectal cancer. Members of this family would probably require only surveillance when they have reached the age for normal population screening in any case unless there are other special reasons to screen such a family.

The mortality rate for major colorectal surgery is less than 3%. This figure however may be doubled or higher for emergency and also in palliative surgery. About one third of deaths are due to post-operative surgical complications mainly associated with infection from anastomotic leaks. Other important causes of deaths are those due to cardiac, respiratory and venous thrombo-embolic problems like pulmonary embolism. Such complications are more common in the elderly patient with coexisting medical problems.

Infective complications may occur as a result of anastomotic leaks, wound infection or intra-abdominal infections. Other sources of infection include peripheral lines and central venous lines as well as respiratory infections. lnfection is also more common In patients with diabetes and other immune-compromised patients Chest infection is more common in patients who are debilitated and immobile as well as in patients who have pre-existing chest problems like bronchiectasis, bronchitis and asthma.

A high incidence of anastomotic leaks can be lowered but no matter how much care a surgeon takes in securing a good anastomosis not all anastornotic leaks can be prevented. Operations such as ultra-low anterior resection in the best of hands are still associated with a anastomotic leak rate of around 5-10% such high risk cases hence, a temporary defunctioning anastomosis is usually made. This stoma can be closed after about a month or so.

Venous thrombosis and pulmonary embolism are also more common in patients who have been lying in bed immobile for some time as well as patients with cancer or who are on oral contraceptives.

The most important factor in deciding if the anus needs to be removed is the distance between the lower edge of the cancer and the top of the anal sphincter muscles. If there is insufficient distance to allow a clear margin for resection to secure the lowest possible recurrence rate then the anus will have to be sacrificed so that complete clearance of the cancer is possible.

Specialist surgeons who deal with colorectal conditions should be able to preserve the anus in cases where the cancer may be as low as 3 to 5 cms from the anal verge depending on the length of the anal canal. However this decision may be influenced by the extent of spread locally, the grade of the cancer, the type of pelvic anatomy and the bulkiness of the cancer itself.

Adjuvant therapy is additional therapy that is added to the primary treatment of the colorectal cancer either before or after surgery in an effort to increase the chances of the patient being totally cured. Normally this means the addition of chemotherapy and/ or radiotherapy.

Conventional Open Surgery Approach
Most conventional open surgeries require a long incision on the abdomen. The average hospital stay is five to seven days or longer depending on the time necessary for bowel activity to return and for the patient to tolerate taking anything by mouth.

Laparoscopic Surgery Approach
In laparoscopic colorectal surgery, usually 3 small incisions are used for instruments and camera. The specimen is removed by slightly enlarging one of the incisions. The benefits of laparoscopic surgeries are related to less surgical trauma. The small incisions utilized in laparoscopic surgery are associated with considerably less pain and the cosmetic results are significantly better. Patients usually have quicker resumption of diet and shorter hospitalization. Laparoscopic surgery is associated with earlier postoperative recovery. Patients who undergo laparoscopic surgery are often discharged from the hospital after 3 days and return to their usual activity much earlier than patients who undergo open surgery. Here at Seow Choen Colorectal Centre Pte Ltd, laparoscopic surgeries are done routinely.