Total Mesorectal Excision (TME): how the operation is performed
Total Mesorectal Excision, internationally known as TME, is the gold standard in rectal cancer surgery. This technique, introduced by Professor Bill Heald in the 1980s, revolutionized rectal cancer treatment, reducing the local recurrence rate from 30-40% to less than 5%.
What is the mesorectum and why must it be removed completely
The mesorectum is the fatty tissue that surrounds the rectum, bounded by its own fascia (the mesorectal fascia). This tissue contains:
- The blood vessels that feed the rectum
- Regional lymph nodes
- Potential cancer cells that have spread from the primary tumor
The TME concept involves removing the rectum together with the entire mesorectum, keeping the mesorectal fascia intact. This ensures that all lymph nodes and any micrometastases are removed en bloc.
Types of TME operations
1. Low Anterior Resection (LAR)
This is the most common operation for rectal cancer in the upper and middle third of the rectum.
- The rectum and mesorectum are removed
- The colon is reconnected to the remaining rectum or to the anal canal (anastomosis)
- The anal sphincter and continence function are preserved
- A temporary protective ileostomy is usually created for 2-3 months
2. Ultra-low anterior resection
For tumors in the lower third of the rectum, the surgeon performs the anastomosis very close to the anal canal. Sometimes a colonic reservoir (J-pouch) is created to improve postoperative bowel function.
3. Abdominoperineal Resection (APR)
When the tumor is very low, invading the anal sphincter, the entire rectum together with the anal canal and sphincter must be removed. This results in a permanent colostomy. APR is necessary in about 10-15% of cases.
4. Transanal local excision (TAMIS/TEM)
For very small and superficial tumors (T1), the tumor can be removed through the anal canal, without major abdominal surgery. This option preserves the rectum but requires rigorous patient selection.
Open vs. laparoscopic vs. robotic surgery
| Approach | Advantages | Disadvantages |
|---|---|---|
| Open | Direct visualization, accessible | Large incision, slower recovery |
| Laparoscopic | Small incisions, fast recovery, less pain | Requires surgical experience |
| Robotic | Superior precision in narrow pelvis, 3D visualization | High cost, limited availability |
Oncological outcomes are equivalent between the three approaches when performed by experienced surgeons. The choice depends on the surgeon’s experience, the patient’s anatomy and the hospital’s equipment.
How the operation is performed
Before surgery
- Neoadjuvant chemoradiotherapy — in most cases, treatment starts with radiotherapy and chemotherapy to shrink the tumor
- ERAS preparation — an enhanced recovery protocol that includes optimized nutrition, early mobilization and reduced surgical stress
- Bowel preparation — cleansing the bowel before surgery
During surgery
- Duration: 2-4 hours (varies with complexity)
- General anesthesia
- The surgeon dissects the rectum and mesorectum following the natural anatomical plane, preserving the pelvic nerves
- Anastomosis (reconnection) is performed and, usually, a protective ileostomy
- The surgical specimen is sent for histopathological examination
After surgery
- Hospital stay: 5-10 days
- Diet: liquids on the first day, then progressive diet
- Mobilization: starts on the first postoperative day
- Ileostomy: requires care and education before discharge
Risks and complications
Every surgical procedure carries risks. Possible complications include:
- Anastomotic leak (5-15%) — leak at the anastomosis, the most common specific risk
- Wound infection
- Urinary dysfunction — difficulty urinating, usually temporary
- Sexual dysfunction — more common in men
- LARS syndrome — postoperative bowel dysfunction (urgency, fragmentation, incontinence)
Long-term outcomes
When TME is performed by an experienced surgeon:
- Local recurrence: less than 5% (vs. 30-40% before TME was introduced)
- 5-year survival: 60-80% (depending on stage)
- Sphincter preservation: possible in 85-90% of cases
Choosing the surgeon matters
Studies show that TME outcomes depend significantly on the surgeon’s volume and experience. Look for:
- A surgeon who performs at least 20-30 rectal cancer operations per year
- A hospital with a multidisciplinary team (surgeon, oncologist, radiotherapist, radiologist, pathologist)
- Willingness to discuss openly their personal experience and outcomes
This article is for informational purposes only and does not replace medical consultation. The surgical decision should be made together with the specialist medical team.