The aim of surgery is to remove the bowel cancer along with normal tissue around it (called a margin), making sure that the remaining bowel still has a good blood supply. Sometimes, quite a large section of bowel needs to be removed in order to achieve this. For a detailed description of bowel surgery please read here.
The most common types of surgery are:
1. A right hemi-colectomy, where the right half of the colon is removed:
Up to 80% of people who have surgery to remove a tumour in the right side of the colon can develop a condition called bile acid malabsorption. The end of the small bowel and the first part of the large bowel are responsible for reabsorbing bile acids and if you lose this section of bowel, it can cause chronic diarrhoea that does not respond to usual medication. If your doctor suspects that you have this condition, it can be diagnosed by a test called a SeHCAT scan and specific medication can be prescribed.
2. A left hemi-colectomy, where the left half of the colon is removed:
3. In an abdomino-perineal resection, the rectum and the anus (including the sphincter muscles) are removed and a new kind of permanent bowel opening is made on the lower left hand side of the surface of the abdomen called a stoma (colostomy):
4. Surgery to remove cancer in the rectum is called an anterior resection:
Depending on the position of the tumour in your rectum, you may need a high anterior resection (4a) or a low anterior resection (4b). Doing a total mesorectal excision at the same time is the gold standard and has been shown to reduce the risk of a recurrence. It involves removing all the visible cancer and surrounding fatty tissue in the pelvis around the rectum, to check the lymph nodes for signs of spread.
Patients who have an anterior resection often need to have a temporary stoma (ileostomy) for a few weeks or months to allow the join in the rectum to heal. The opening onto the abdomen for this is usually on the right hand side.
Other, less common types of surgery you might be offered are:
5. Sigmoid colectomy where the sigmoid colon is removed and the two ends are joined back together:
6. Hartmann’s procedure where the sigmoid colon and upper rectum are removed, and an end colostomy formed (as for an abdomino-perineal resection). This operation is not as common as it used to be, but is still carried out when necessary, often during emergency surgery:
7. Total colectomy where the entire colon is removed, leaving behind the rectum. This will result in either a permanent ileostomy or your small bowel will be joined to your rectum:
8. Pan proctocolectomy where the colon, rectum and anus are removed, and results in a permanent ileostomy: