From the Guidelines
Complete resection in Low Anterior Resection (LAR) for rectal cancer primarily involves Total Mesorectal Excision (TME) to ensure optimal oncological outcomes, as recommended by the NCCN guidelines 1.
Key Components of Complete Resection in LAR
- Achieving a clear circumferential resection margin (CRM) with negative margins all around the specimen
- Obtaining adequate distal and proximal margins, typically 2 cm distally for mid and upper rectal cancers, though 1 cm may be acceptable for low rectal tumors
- Total mesorectal excision (TME) involving complete removal of the rectum along with its surrounding mesorectal fat and lymphatic tissue as an intact unit
- Proper lymph node dissection to ensure adequate staging and treatment, with at least 12 lymph nodes typically recommended for examination
- En bloc resection of invaded adjacent structures to maintain oncological principles
- Careful handling of the specimen to avoid perforation, as tumor perforation significantly increases the risk of local recurrence
Importance of TME in LAR
TME is a crucial component of LAR, as it facilitates adequate lymphadenectomy and improves the probability of achieving negative circumferential margins 1. The NCCN panel recommends wide TME to ensure optimal oncological outcomes. Additionally, the quality of the mesorectal specimens should be scored according to the guidelines provided in the Dutch Rectal Cancer TME Trial, which are endorsed by the NCCN panel 1.
Impact on Morbidity, Mortality, and Quality of Life
The components of complete resection in LAR collectively ensure optimal oncological outcomes, directly impacting local recurrence rates and overall survival in patients undergoing LAR for rectal cancer. While the quality of life between patients with or without a permanent colostomy appears to be fairly comparable 1, the goal of LAR is to maintain sphincter function and avoid the need for a colostomy, thereby improving the patient's quality of life. Therefore, TME and adequate margins are essential components of complete resection in LAR, prioritizing morbidity, mortality, and quality of life as the primary outcomes 1.
From the Research
Components of Complete Resection in Low Anterior Resection (LAR)
- Complete resection in LAR involves the removal of the rectum and mesorectum, with a minimal distal margin of 2cm and circumferential radial clearance 2
- Total mesorectal excision (TME) is a critical component of complete resection in LAR, ensuring the removal of the entire fascia with the enclosed mesentery of the rectum 2
- A complete and near complete TME grade can be achieved in 94.4% of cases, with a low rate of positive circumferential radial margin (+CRM) 3
- Low anterior resection with sphincter salvage can be achieved in 87% of cases, with some patients requiring intersphincteric resection 3
Technical Aspects of Complete Resection in LAR
- Laparoscopic approach for rectal cancer treatment is technically feasible and can provide benefits such as short hospitalization, less pain, and improved quality of life 2
- Transanal total mesorectal excision (taTME) is a surgical approach for low rectal cancer that can achieve good short-term outcomes and facilitate R0 resection 3
- A 2-team approach can be used in taTME, with laparoscopic or robotic abdominal assistance, to achieve complete resection 3
Outcomes of Complete Resection in LAR
- Complete resection in LAR can achieve good treatment results, with an actuarial 5-year survival rate of 73% and a low rate of pelvic recurrence 4
- The use of neoadjuvant therapy and selective radiation can achieve high rates of R0 resection and low rates of local recurrence 5
- Complete resection in LAR can also achieve good functional outcomes, with long-term preservation of anal sphincter function in more than 90% of patients 4