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Colon Cancer

Colon cancer is cancer of the large intestine (colon), the lower part of your digestive system. Rectal cancer is cancer within the rectum, which forms the last several inches of the colon. Together, they’re often referred to as colorectal cancers.

Rectal cancer often presents late as symptoms are very similar to those of benign anal diseases like piles and constipation and often ignored until it is too late.

Whilst all cancers are best treated as early as possible, this is especially important in rectal cancer. The rectum is a short tube about 12 cm long and is next to the anus. Those cancers that present late or are very close to the anus may need to be treated by total removal of the anus. If this is needed, the patient may have to wear an artificial anus constructed by bringing a loop of colon out through the abdominal wall and closing off the natural anal opening. Early detection may allow treatment without colon surgery or minimal access or minimally destructive surgery which is that much better for patients. Furthermore as the rectum sits within the narrow confines of the pelvis, the bigger the cancer the more difficult it is to get a wide clear margin which is important for cancer clearance. Males of course have a much narrower pelvis than females and fat males are the most difficult to manage in this regard.

Furthermore the earliest stage rectal cancers will not have spread outside the innermost lining of the rectum. Therefore the earlier the stage, the better the chances of survival for the patient. The second important factor in prognosis is the grade of the cancer. Thus poorly differentiated cancers have a worse prognosis than well differentiated cancers. Basically differentiation is how much a cancer cell resembles or does not resemble a normal rectal cell. The less the resemblance, the poorer the differentiation. And as mentioned already, rectal surgery is difficult at the best of times due to the narrow confines of the pelvis. The skill of the colorectal surgeon in dissection and removal of the cancer with a sufficient margin is therefore paramount in improving the patient’s chance of survival. In this regard therefore, rectal cancer may be more dangerous than cancers elsewhere in the body as almost nowhere else is surgical skill and technique so important as in patients with rectal cancer; first to cure the cancer and second to prevent unneeded removal of the anus.

Risk factors for rectal cancers are the same as risk factors for colon cancer. These include a family history of colorectal cancer and therefore genetic predisposition is very important. Patients with a family history of colorectal cancer should be advised for screening at least 10 years earlier than the age of the youngest affected member of the family. Those with a history of colorectal polyps should also be screened appropriately by colonoscopy to remove these polyps at regular intervals. These intervals may vary according to the sort of family history present as well as the number and type of colorectal polyps present. A history of inflammatory bowel disease like ulcerative colitis and Crohn’s disease is important as these predispose to the development of colorectal cancer.

The best way of preventing and minimising rectal cancer is to have regular colonoscopic screening, Such a screening removes pre-cancerous polyps which reduces dramatically the risk of getting rectal cancer.

Rectal cancer is often said to be a surgical disease which means that surgery is the main and first mode of treatment. Early stage rectal cancers e.g. a carcinomatous polyp may well be treated by colonscopic or transanal removal without the need for major ablative surgery. Late stage rectal cancers may need chemotherapy, with or without radiotherapy, to shrink the cancer before surgery or to kill off any possible residual cancer cells after surgery. Most rectal cancers including the middle staged ones, however will need surgical removal or what is called radical rectal cancer surgery.

This sort of surgery where the rectum and all surrounding lymph nodes and vascular supply are removed or Total Mesorectal Excision (TME) Rectal Surgery may be performed by open method or laparoscopic or even robotic method. I prefer to use a combination of laparoscopic and robotic surgery for rectal cancer surgery as surgery with just three or four tiny holes enables TME to be performed and yet with minimal trauma to the patient.

Laparoscopic or robotic surgery for rectal cancer is easy and when well done, gives equivalent cure rates to open surgery but with a much smaller cosmetic scar, and greatly improved recovery and hospitalization time. Many patients are even able to play golf after such major rectal or colon surgery one week after it has been done. Most patients who undergo TME are those who have low rectal cancer. Such patients may require a temporary stoma bag where faeces is collected via an outlet on the abdominal wall. This is to minimize the bad effects of a possible leak from the very low intestinal joint next to the anus. High joints as those following higher placed rectal cancers do not normally need a temporary stoma bag.

In a very small number of patients where the rectal cancer had invaded the anal canal then total ablation of the anus may be needed. In such a situation the stoma bag is permanent. However even in this situation, we now have the technology to reconstruct a new anus from a long thigh muscle called the gracilis. Such patients can have their anus functioning in the original position again even after it had been removed to save his life from cancer.