High-Dose-Rate Brachytherapy for Vaginal Rhabdomyosarcoma (RMS): Lessons Learned at a Single Institution

Area of Science:

• Pediatric Oncology
• Radiation Oncology
• Gynecologic Oncology

Background:

• Botryoid rhabdomyosarcoma (RMS) is a rare malignancy affecting the vaginal wall in young girls.
• Standard treatment involves chemotherapy, but local control remains crucial to prevent relapse.
• Intravaginal brachytherapy (IVRT) offers a potential organ-sparing local treatment option.

Purpose of the Study:

• To evaluate the efficacy and safety of high-dose-rate IVRT for local control of vaginal RMS.
• To determine optimal IVRT dosing and delivery for minimizing local recurrence.
• To assess the oncologic outcomes and potential long-term sequelae.

Main Methods:

• Retrospective review of 12 patients with vaginal RMS treated with high-dose-rate IVRT from 2010-2024.
• Patients received multiagent chemotherapy with or without surgical resection of gross residual disease.
• CT simulation under anesthesia and cylindrical applicators were used for IVRT delivery; Kaplan-Meier analysis assessed outcomes.

Main Results:

• Five-year local control was 75%, with all relapses occurring in patients receiving lower doses (2100 cGy).
• Patients receiving higher doses (≥2800 cGy) and full vaginal coverage experienced no local failures.
• Five-year overall survival was 86%, with salvage therapy curing 2 of 3 patients with treatment failure.

Conclusions:

• High-dose-rate IVRT is an effective local treatment for vaginal RMS with favorable oncologic outcomes.
• A dose of 2800 cGy in 7 fractions to the entire vagina may optimize recurrence prevention.
• Further follow-up is necessary to evaluate long-term functional outcomes like ovarian, reproductive, and sexual health.