Vaginal Brachytherapy Recommendations for Endometrial Cancer
For vaginal brachytherapy in endometrial carcinoma, the target should be limited to the upper vagina with a dose of 7 Gy × 3 fractions prescribed at 0.5 cm depth or 6 Gy × 5 fractions prescribed to the vaginal surface when used alone. 1
Target Length and Location
- The target for vaginal brachytherapy after hysterectomy should be limited to the upper vagina only 1
- The most common vaginal length treated is 4 cm according to survey data of radiation oncologists 2
- Treatment should be directed at the vaginal cuff, which is the most common site of local recurrence 3
Dose Recommendations
For High-Dose Rate (HDR) Vaginal Brachytherapy Alone:
- 7 Gy × 3 fractions prescribed at a depth of 0.5 cm from the vaginal surface 1
- OR 6 Gy × 5 fractions prescribed directly to the vaginal surface 1
For HDR Vaginal Brachytherapy as a Boost After External Beam Radiation Therapy (EBRT):
- 4-6 Gy × 2-3 fractions prescribed to the vaginal mucosa 1
- More specifically, 5-6 Gy × 2 fractions to the vaginal mucosa is commonly used 1
Technical Considerations
- The dose should be prescribed to either the vaginal surface or at a depth of 0.5 cm from the vaginal surface, depending on the chosen regimen 1
- The largest diameter applicator that comfortably fits should be selected to ensure close mucosal apposition 4
- Three-dimensional planning is used by most practitioners (83.2%), typically for the first fraction only 2
- Optimization points should be placed at both the apex and lateral vagina for optimal dose distribution 2
Clinical Considerations
- Lymph node dissection status and number of nodes removed influence treatment decisions for most practitioners 2
- Vaginal brachytherapy alone is appropriate for high-intermediate risk disease, while high-risk patients may benefit from additional pelvic external beam radiation therapy 3
- Patients treated with vaginal brachytherapy are prone to vaginal stenosis, which can impair sexual function; vaginal dilators can be used starting 2-4 weeks after treatment completion 1
Dosimetric Considerations
- Surface prescription provides more uniform doses at all depths in the target volume, whereas 0.5-cm depth prescription creates larger dose variations at the cylinder surface 5
- Dosimetric uncertainty increases significantly (>30%) with shorter tip space, so adequate coverage of the vaginal apex is essential 5
- Extreme hot (>150%) and cold spots (<60%) can occur if no optimization points are placed at the curved end of the applicator 5
Following these evidence-based recommendations for vaginal brachytherapy in endometrial cancer will help ensure optimal local control while minimizing treatment-related toxicity.