Low anterior resection removes rectal cancer together with its surrounding fatty envelope (total mesorectal excision – TME), preserving the sphincter and restoring continuity. It is performed laparoscopically or robotically, often with a temporary protective stoma.
What is the operation?
It is the resection of the rectum with sphincter preservation and restoration of continuity (colorectal or coloanal anastomosis), for cancer of the mid/upper rectum. It allows a permanent colostomy to be avoided when oncologically safe.
The foundation of the operation is total mesorectal excision (TME): removing the rectum together with its surrounding fatty/lymphatic envelope as a single specimen, along embryonic anatomical planes — the technique that dramatically reduces local recurrence.
When is it needed?
It is indicated for mid and upper rectal cancer where an adequate distal margin can be achieved with sphincter preservation. For locally advanced tumours, neoadjuvant chemoradiotherapy often precedes surgery, decided by the multidisciplinary team.
When the tumour invades the sphincter or lies very low, abdominoperineal resection is the alternative.
Preparation
A pelvic MRI is essential for precise staging and margin assessment, together with colonoscopy, CT and CEA. Stoma site marking with a specialist nurse, thromboprophylaxis and ERAS preparation are arranged.
How it's done
The operation is performed chiefly laparoscopically or robotically — robotics offers advantages in the narrow pelvis. The rectum is mobilised along TME planes, with careful preservation of the pelvic autonomic nerves (urinary/sexual function), and removed with clear margins.
A low anastomosis follows, often with a protective temporary ileostomy to safeguard it, which is closed at a second stage. Integrity of the mesorectal envelope is checked as a quality marker.
Robotic
The robotic approach offers excellent access and precision in the narrow pelvis — ideal for TME.
Laparoscopic
Resection through small incisions with oncological adequacy and faster recovery.
Diverting stoma
A temporary stoma that protects the low anastomosis and is closed at a second stage.
Recovery
With ERAS, mobilisation/eating start early and hospital stay is usually 4–7 days. Those with a temporary ileostomy are trained in its management; reversal is planned later.
After continuity is restored, low anterior resection syndrome (LARS) — changes in stool frequency/urgency — may occur and usually improves over time with specialist support.
Risks & outcomes
The main specific complication is an anastomotic leak (higher risk the lower the anastomosis), hence the protective ileostomy. Others: urinary/sexual dysfunction, LARS, ileus.
Quality markers: a complete (R0) resection, an intact mesorectum, adequate lymph nodes. "Success" means an oncologically safe resection with preserved sphincter and function.
Frequently asked questions
Will my sphincter be preserved?
The aim is to preserve the sphincter whenever oncologically safe. It depends on the position and extent of the tumour and is decided after precise staging.
Why might I need a temporary stoma?
In low anastomoses, a temporary diverting stoma protects the anastomosis while it heals and is usually closed at a second stage.
Will I need radiotherapy or chemotherapy?
In many rectal cancers, neoadjuvant therapy comes first. The decision is made at the tumour board based on staging.
What is TME?
It is total mesorectal excision — removing the rectum with its surrounding envelope intact, a decisive factor in the oncological outcome.