From the Guidelines
TEM (Transanal Endoscopic Microsurgery) is a minimally invasive surgical technique used to remove rectal lesions and early-stage rectal cancers, particularly valuable for removing benign polyps, early T1 rectal cancers, and selected T2 tumors. This technique involves inserting a specialized operating proctoscope into the rectum, which provides magnified visualization and allows surgeons to precisely excise lesions up to 15-20 cm from the anal verge 1. During the procedure, the rectum is distended with carbon dioxide, creating a working space for the surgeon to use specialized instruments to remove the lesion with adequate margins while preserving the rectal wall integrity.
The advantages of TEM include less pain, faster recovery, no external incisions, and preservation of anal sphincter function compared to traditional surgery 1. However, TEM requires specialized equipment and training, and may not be suitable for larger or more advanced tumors that require lymph node removal. According to the most recent guidelines, TEM is recommended for early-stage rectal cancers, particularly for T1 tumors without adverse features, and may be considered for selected T2 tumors 1.
Some key points to consider when using TEM include:
- The procedure typically takes 1-3 hours under general anesthesia, with most patients discharged within 1-3 days 1.
- TEM involves a full-thickness excision performed perpendicularly through the bowel wall into the perirectal fat, with negative (>3 mm) deep and mucosal margins required 1.
- The locally excised specimen should be oriented and pinned before fixation and brought to the pathologist by the surgeon to facilitate an oriented histopathologic evaluation of the specimen 1.
- Data are limited on long-term patient outcomes, including risk of local recurrence, for patients undergoing local excision for T2 tumors, and further studies in this area are needed 1.
Overall, TEM is a valuable technique for the treatment of early-stage rectal cancers, offering a minimally invasive alternative to traditional surgery with potential benefits for patient outcomes, including reduced morbidity, mortality, and improved quality of life 1.
From the Research
Definition and Purpose of TEM
- Transanal endoscopic microsurgery (TEM) is a minimally invasive technique for excision of rectal tumors that avoids conventional pelvic resectional surgery along with its risks and side effects 2.
- The purpose of TEM is to provide a safe and effective method for excision of benign and malignant rectal tumors, allowing for curative resection, histopathologic staging, and palliative resection in select cases 3.
Indications for TEM
- TEM can be offered for curative resection of benign tumors, carcinoid tumors, and select T1 adenocarcinomas 3.
- It is also used for histopathologic staging in indeterminate cases and palliative resection in patients medically unfit or unwilling to undergo radical resection 3.
- TEM is indicated for early rectal cancer, with proper patient selection being crucial to ensure oncological safety 4.
Procedure and Outcomes
- TEM involves the use of a special instrument to remove the tumor from the rectum, with enhanced visibility, superior optics, and longer reach permitting a more complete excision and precise closure 5.
- The procedure has been shown to be safe, with low local recurrence rates and high survival rates for pT1 rectal cancers 5.
- Close follow-up is necessary to permit curative salvage for recurrent cases 5.
- TEM has been found to have no permanent impact on anorectal function, with transient anal resting pressure weakening being a possible temporary side effect 4.
Comparison with Other Techniques
- TEM has emerged as an alternative to traditional surgical methods, such as transanal minimally invasive surgery (TAMIS), which uses ordinary laparoscopic instruments to achieve high-quality local excision 2.
- TAMIS has been found to be a feasible and safe treatment option for early rectal cancer, with the potential to be easier to perform, cost-effective, and less traumatic to the anal sphincter compared to TEM 2.