From the Guidelines
Transanal excision is appropriate for select anal cancers, specifically T1N0 squamous cell carcinomas that are small, well-differentiated, and located in the distal anal canal or anal margin. These tumors should be less than 2 cm in diameter, occupy less than 30% of the anal circumference, and have no lymph node involvement 1. The tumor should be mobile, accessible from below, and preferably located within the distal 5 cm of the anal canal.
- Key considerations for transanal excision include:
- Tumor size and location
- Histological type (squamous cell carcinoma)
- Depth of invasion (T1N0)
- Absence of lymph node involvement
- Patient factors, such as overall health status and ability to tolerate more extensive procedures
- Transanal excision allows for complete removal with a 1 cm margin while preserving sphincter function, but is generally not recommended for more advanced tumors, those with lymph node involvement, or aggressive histological features, as these typically require more extensive treatment such as chemoradiation therapy 1.
- The decision to perform transanal excision should be made on a case-by-case basis, taking into account the individual patient's characteristics and the specific features of the tumor 1.
From the Research
Anal Cancers Eligible for Transanal Excision
- Transanal excision can be considered for early-stage low rectal cancers with favorable histology, as shown in a study from 2.
- This approach may be suitable for T1 and T2 rectal cancer, with the efficacy of local resection versus adjuvant therapy being evaluated in a study from 3.
- For anal squamous cell carcinoma (SCC), transanal excision may be an option for stage I disease not involving the sphincter, as mentioned in a study from 4.
- Transanal excision has also been compared to major surgery for T1 rectal cancer, with results indicating higher rates of local recurrence and inferior survival in the transanal excision group, as reported in a study from 5.
Considerations for Transanal Excision
- The decision to undergo transanal excision should be based on individual patient factors, including tumor size, location, and histology.
- The presence of unfavorable histologic characteristics, such as lymphovascular invasion, may preclude transanal excision as a treatment option.
- Adjuvant therapy may be necessary in some cases, particularly if margins are close or if there is a high risk of recurrence.
- The role of transanal excision in the treatment of anal intraepithelial neoplasia (AIN) is still being evaluated, with some studies suggesting that it may be effective in reducing the risk of progression to anal SCC, as discussed in a study from 6.