Colorectal Resection

The large bowel absorbs water and stores stool before it leaves the body. Colorectal resection removes the part affected by disease and rejoins the remaining ends, a join called an anastomosis. The operation is named after the segment removed: a right or left hemicolectomy, a sigmoid colectomy, an anterior resection of the rectum, or a total colectomy when most of the colon is removed. In cancer surgery the surgeon removes the tumour with a margin of healthy bowel together with the blood vessels and lymph nodes that drain it, which is essential for staging and lowers the risk of recurrence; in rectal cancer the fatty envelope around the rectum is removed intact, a technique called total mesorectal excision. When a safe join is not possible, or to protect a low join while it heals, the end of the bowel is brought out onto the skin as a stoma, which drains into a bag.

The commonest reason for colorectal resection is cancer of the colon or rectum, often found after symptoms such as bleeding or a change in bowel habit, or through screening colonoscopy. For rectal cancer, radiotherapy or chemotherapy may be given before surgery, and for some colon cancers chemotherapy follows it, as decided by a multidisciplinary tumour board. Resection is also recommended for diverticular disease that causes repeated or complicated attacks, such as an abscess, a narrowing or a fistula to the bladder; for Crohn's disease with narrowing or fistulas, and ulcerative colitis that does not respond to medicines or shows precancerous changes; for large polyps that cannot be removed safely by endoscopy; and for emergencies such as obstruction, perforation, severe bleeding or a twisted bowel. Some people with inherited syndromes that carry a very high cancer risk choose preventive removal of the colon.

Colorectal resection is done under general anaesthesia, often with an epidural, spinal injection or nerve block to reduce pain afterwards. In laparoscopic surgery the surgeon works through several small cuts and one slightly larger one through which the bowel is removed; robotic surgery uses the same keyhole approach with wristed instruments controlled from a console, which can help in the narrow pelvis during rectal surgery. Open surgery through a longer midline incision is chosen for large tumours, extensive scar tissue or emergencies. The diseased segment is freed, its blood vessels are divided, and it is removed. The ends are joined with staples or stitches, and the blood supply and integrity of the join are checked. If a stoma is needed, it is formed through a small opening in the abdominal wall at a site marked before surgery. Depending on the segment and approach, the operation takes about 2 to 5 hours.

Candidacy depends on the disease, its stage and your general fitness. For cancer, staging with a CT scan of the chest, abdomen and pelvis, an MRI of the pelvis for rectal tumours, blood tests including a tumour marker, and a full colonoscopy is completed before a plan is agreed. Heart and lung function, nutrition and anaemia are assessed, and anaemia is often corrected with iron before surgery. Prehabilitation, meaning walking, breathing exercises, good nutrition and stopping smoking in the weeks before, helps recovery. A stoma nurse may mark a possible stoma site and explain what living with one involves, even if a stoma may not be needed. Depending on the operation, you may take a bowel preparation and antibiotics by mouth beforehand. International patients can send scans, colonoscopy and pathology reports in advance, so the team can review the case and suggest a timeline before travel.

Recovery follows an enhanced recovery programme: you are encouraged to drink and eat within the first day or two, sit out of bed and walk early, and catheters and drains are removed as soon as possible. Pain is controlled with a combination of medicines. Many people go home after about 4 to 7 days, longer after rectal or open surgery or if complications occur. Bowel function returns gradually and may be irregular for weeks or months, particularly after rectal surgery. If you have a stoma, the stoma team teaches you to care for it before discharge. For travel, plan about two to three weeks abroad: time for the operation, the hospital stay, a wound review and the pathology results, which guide whether chemotherapy is advised. Further cancer treatment and long-term follow-up are often arranged closer to home with your local doctors, using the full surgical report.

Colorectal resection is major surgery, and although it is routine in experienced colorectal units, it carries real risks. The specific one is an anastomotic leak, where the join does not heal fully and bowel contents escape; it occurs in a small proportion of patients, is more likely with low rectal joins, and may require antibiotics, drainage, further surgery or a stoma. Other risks include wound infection, bleeding, blood clots, chest infection, a temporary pause in bowel activity called ileus, and later adhesions or hernia. After rectal surgery many people experience changed bowel habit, such as frequency, urgency or clustering, known as low anterior resection syndrome, which often improves over a year or two; bladder and sexual function can also be affected. For cancer, outcomes depend largely on stage, and complete removal with clear margins and enough lymph nodes is the foundation for cure, supported where needed by chemotherapy.