Overview
Squamous cell carcinoma of the anal canal (SCCA) is a malignancy arising from the squamous epithelium of the anal canal. Guidelines exist for contouring and treatment of early-stage SCCA using intensity-modulated and image-guided radiation therapy (RT) 1.Diagnosis
Management
For early-stage (T1-2 N0 M0) SCCA, treatment recommendations are customized for radiation therapy 1.
Treatment is typically delivered in the supine, frog leg position with a customized immobilization device and daily image-guided RT 1.
Vaginal dilators may be used daily during RT to maximize genitalia sparing 1.
The primary clinical target volume includes a 10-mm margin on the gross tumor plus the anal complex 1.
Elective lymph node clinical target volume is defined by a 7-mm expansion on blood vessels, refined by anatomic location 1.
A 5- to 10-mm planning target volume (PTV) margin is suggested, based on institutional setup and patient specifics 1.Special Populations
Key Recommendations
For early-stage (T1-2 N0 M0) anal cancer, customized radiation treatment recommendations are provided for intensity-modulated and image-guided RT 1. (Evidence: Expert opinion)
Treatment should be delivered in the supine, frog leg position with a customized immobilization device and daily image-guided RT 1. (Evidence: Expert opinion)
A 10-mm margin on the gross tumor plus the anal complex should be used to create the primary clinical target volume 1. (Evidence: Expert opinion)
Elective lymph node clinical target volume should start with a 7-mm expansion on blood vessels, further refined by anatomic location 1. (Evidence: Expert opinion)References
1 Damico N, Meyer J, Das P, Murphy J, Miller E, Koontz B et al.. ECOG-ACRIN Guideline for Contouring and Treatment of Early Stage Anal Cancer Using IMRT/IGRT. Practical radiation oncology 2022. link