Three-dimensional image-based high-dose-rate interstitial brachytherapy for vaginal cancer

Area of Science:

• Gynecologic Oncology
• Radiation Oncology
• Medical Physics

Background:

• Vaginal cancers are rare malignancies requiring precise treatment strategies.
• Three-dimensional (3D) image-based high-dose-rate interstitial brachytherapy (HDRB) offers potential for targeted radiation delivery.
• Evaluating outcomes of HDRB is crucial for optimizing treatment protocols.

Purpose of the Study:

• To assess the dosimetric and clinical outcomes of 3D image-based HDRB for vaginal cancers.
• To evaluate the efficacy and toxicity of this treatment modality.

Main Methods:

• Thirty patients with vaginal cancers received 3D HDRB using the Syed-Neblett template.
• CT scans guided treatment planning, contouring of clinical target volume (CTV) and organs at risk.
• Patients received external beam radiation therapy followed by HDRB, with doses normalized to a biologically equivalent dose (BED).

Main Results:

• The study included 17 primary and 13 recurrent vaginal cancer cases.
• Median D(90) for high-risk CTV was 74.3 Gy. Organs at risk received median BEDs of 55.0 Gy (bladder), 56.3 Gy (rectum), and 50.0 Gy (sigmoid).
• One- and two-year locoregional survival rates were 84.4% and 78.8%, respectively. No Grade ≥3 gastrointestinal complications occurred; two cases had Grade 3/4 vaginal complications.

Conclusions:

• 3D HDRB demonstrates good local response in vaginal cancer treatment.
• The employed fractionation schedule yields acceptable toxicity profiles.
• Initial results suggest 3D HDRB is a viable option for vaginal cancer management.