Everything you need to know about colon cancer

Colon cancer is the fourth most common cancer in the UK with over 40,000 new diagnoses in the UK every year. It affects one in 14 men and one in 19 women during their lifetime with the vast majority being over the age of 50.

What causes colon cancer?

Cancer of the colon and rectum is a process where the natural control mechanisms of cell proliferation are lost through a series of genetic mutations leading to uncontrolled cell division. The majority of cases occur in the large bowel. Small polyps, measuring only 1mm in diameter, develop and then gradually enlarge in size over the next 5 to 10 years ultimately turning into cancer through genetic mutation

How is colon cancer diagnosed?

Benign polyps can easily be diagnosed during routine diagnostic colonoscopy which is the fiber optic examination of the large bowel when they can be removed and at the same time removing the risk of bowel cancer.

What are the symptoms of colon cancer?

The symptoms of colorectal cancer tend not to arise until the tumor has reached a significant, critical size. The key thing here is acting quickly when symptoms arise and early investigation because the earlier a tumour is identified, the earlier the stage of the cancer, the more likely it is to be curable.

Prevention is better than cure

The common symptoms of bowel cancer include bleeding from the bottom, either fresh blood on the toilet paper or in the toilet. Any change in the bowel habit from the norm, including looser or more frequent stool and constipation, is of concern. Abdominal pain or weight loss are also worrying. Finally, if the general practitioner has done some blood tests, any iron deficiency anemia suggests chronic blood loss from the gut.

Minimally-invasive techniques

The latest surgical techniques are minimally-invasive. During a colonoscopy, which is the fiber optic examination of the bowel, polyps are routinely removed and some of these larger polyps may contain a very early cancer. And in these patients, that polyp removal may be the only treatment the patient needs but with no requirement of surgery. Also in a small percentage of patients, perhaps less than 5% of patients with rectal cancer, if the tumour is very early, it can be removed trans-anally (through the bottom) without the need for removal of a large segment of colon.

Surgical removal

But for the vast majority of patients, the affected segment of bowel will need to be removed surgically. The big advance in the last 15 years has been keyhole surgery (or laparascopic surgery) where the bowel is removed with tiny cuts. There is much less post-operative pain and a quicker return to normal activities. There’s also a cosmetic component, as opposed to traditional open surgery where there would have been a large midline scar and a more painful recovery.

Screening for colon cancer

The first method of screening in the UK is using fecal occult blood testing kits. These kits are sent out to the patient’s home and come with instructions as to how to apply a small stool sample onto the kit. The kit is then sent back to the central laboratories and then analysed for small invisible amounts of blood within the stool which is what colorectal cancer will produce. The second type of bowel screening in the UK is known as Bowel Scope, where patients aged over 55 are invited to come along for a one-off fiber optic camera examination of the lowest part of the colon. It’s a relatively easy procedure that takes about five or ten minutes. It is thought that two cases are prevented and one life is saved from every 300 people screened.