Colon Cancer

Colon Cancer

Colon cancer is the second most common cause of cancer in the Western World. If a cancerous growth is already present, it can be diagnosed through a screening procedure called a colonoscopy. Surgery can then be planned. The sooner this is done, the better chance there is of a cure.


A colonoscopy is the most thorough method of screening the colon (large intestine) for possible cancer or other pathology. It is performed by using a colonoscope which is a sophisticated instrument with a fibre optic camera on the end. This is inserted into the anus and steered through the entire length of the colon (+/- 1.5 metres), while the patient is under local anaesthetic or sedation. Dr. Marr usually does this in his rooms but it can also be done in hospital.

During a colonoscopy, Dr. Marr not only checks the colon (or large intestine) thoroughly, but can also biopsy or remove polyps or other abnormalities at the same time. If you have polyps in the colon, even though they may not cause symptoms, they can be detected and removed during a colonoscopy before they become malignant, reducing your risk of getting colon cancer by up to 70%.

Frequently Asked Questions

How do I prepare for a colonoscopy?

In order to look inside the colon, it needs to be empty and as clean as possible.

To do this, Dr. Marr has you take four Senekot tablets two nights before the procedure to start things off. Then at noon the day before the procedure you drink the first of four glasses of “Picoprep”, drinking the following three glasses at two hourly intervals until the last one at 6 pm. From 24 hours before the procedure you must only drink clear fluids including water, black tea, clear fruit juice (not orange juice), clear soup, jelly, Bovril. You should drink at least one glass of water per hour from the start of the Picoprep.

Can I work after the procedure?

You will probably feel drowsy and find it difficult to concerntrate after taking the sedation so Dr.Marr recommends that you take a day's leave to have the procedure. However, if the procedure is performed early in the morning, you should be fine by the afternoon.

Can I drive after the procedure?

No. You will need someone to take you home.

Is it painful?

It may be painful. We use strong painkillers during the procedure but thereafter there is no pain.

Are there risks?

Yes, there is a 0.3% chance of perforating the colon. This would then require surgery to repair.

Can I have the procedure if I am on blood-thinning agents?

Yes. Warfarin needs to be stopped four days before. Disprin/Ecotrin should be stopped two weeks before.

Should I take my regular medication on the morning of the procedure?

Yes, other medication should be taken as normal. If you are diabetic you should contact Dr. Marr’s office for specific instructions.

How long do results take to come back?

Dr. Marr knows the outcome of the colonoscopy immediately. Pathology specimens take 48 hours.

Can I watch the procedure on the screen?