Phase II trial of image-based high-dose-rate interstitial brachytherapy for previously irradiated gynecologic cancer

Purpose: To report the disease-free Grade ≥3 complication-free survival of a Phase II protocol of reirradiation with high-dose-rate (HDR) interstitial brachytherapy (ITB) in previously irradiated gynecologic cancer.

Methods and materials: Fifteen patients with previously irradiated cervical (n = 6), endometrial (n = 6), and vulvovaginal tumors (n = 3) were treated with HDR-ITB alone to a median dose of 38 Gy in 8 b.i.d. fractions over 4 consecutive days. Prior treatments included surgery (n = 12; 80%), external irradiation (n = 15; 100%), and brachytherapy (n = 9; 60%). Average clinical target volume Size was 60.9 cc (range, 14.8-165.3 cc), and median time to reirradiation was 3.9 years (range, 0.4-22.7 years).

Results: With a median followup of 2.8 years (range, 1.2-9.2 years), 3 patients (20.0%) developed Grade ≥3 toxicity consisting of Grade 3 intestinal obstruction (n = 1), Grade 4 rectovesical fistula (n = 1), and Grade 5 intestinal obstruction (n = 1). Six patients remain alive and without evidence of disease at last followup. Two patients are alive with disease progression, and 7 patients have died, 4 of them from disease progression and 3 from other causes. The 2-year disease-free Grade ≥3 complication-free survival was 40%.

Conclusions: HDR-ITB alone is a reasonable salvage treatment option in a significant number of patients with previously irradiated gynecologic tumors.