High-dose-rate interstitial brachytherapy for gynecologic malignancies

Area of Science:

• Oncology
• Radiation Oncology
• Gynecologic Oncology

Background:

• Locally advanced cervical and vaginal cancers present treatment challenges, especially with distorted anatomy.
• Intracavitary brachytherapy may be unsuitable for certain patient cases.
• External beam radiotherapy (EBRT) combined with brachytherapy is a standard treatment modality.

Purpose of the Study:

• To evaluate the efficacy and safety of high-dose-rate interstitial brachytherapy (HDRB) for locally advanced cervical and vaginal cancers.
• To assess treatment outcomes including local control, survival, and toxicity.
• To determine the effectiveness of a single HDRB procedure with a specific fractionation schedule.

Main Methods:

• Retrospective analysis of 16 patients with locally advanced cervical/vaginal cancer treated between 1998-2004.
• Combination treatment with whole pelvis EBRT followed by HDRB using a Syed-Neblett template.
• Concurrent chemotherapy was administered to 75% of patients.
• CT-based treatment planning for dose prescription to the tumor volume.

Main Results:

• Median cumulative biologic effective dose to tumor volume was 78.9 Gy10.
• Complete response achieved in 81% of patients; 5-year actuarial local control was 75%.
• 5-year cause-specific survival was 64%; local control was 63% for cervical and 100% for vaginal cancer.
• No acute Grade 3/4 morbidity; 5-year actuarial rate of Grade 3/4 delayed morbidity was 7%.

Conclusions:

• A single interstitial implantation procedure with five fractions of 3.75 Gy is an effective and safe fractionation schedule for HDRB.
• Integration of imaging modalities aids in reducing dose to critical organs.
• Ongoing studies aim to confirm long-term efficacy.