A single-institution review of image-guided brachytherapy for vaginal malignancies using customized molded applicators and interstitial needles

Abstract

Purpose:To review a single-institution's pattern of practice, dosimetry results, and clinical outcomes for patients with unresectable malignancies of vagina, vulva, or urethra, receiving brachytherapy using customized vaginal moulds with or without interstitial needles.Material and methods: Twenty-one consecutive patients were reviewed. Patients were treated using customized moulds with or without interstitial needles, implanted with a free-hand technique. Technical implementation, such as type of implant and imaging used were recorded. D 90 and D 98 of clinical target volume (CTV), D 0.1cc of urethra, and D 2cc and D 0.1cc of bladder and rectum were analyzed. Any adverse clinical outcomes were reported.Results: Eleven patients experienced endometrial cancer recurrences, one a cervical cancer recurrence and nine vaginal or peri-urethral primary disease. After a median follow-up of 3.5 years, local control was achieved in 14 patients (67%). Median D 98 and D 90 to CTV was 73.7 Gy and 78.3 Gy, respectively. One patient died from disease progression, one developed distant metastasis, and seven failed locally. Median D 2cc to bladder was 64.8 Gy, with low-grade toxicity reported. Median D 2cc to rectum was 62.9 Gy, with low-grade toxicity and one case of rectal proctitis was observed. Median urethral D 0.1cc was 66 Gy, with no toxicity reported. One patient suffered from a sacral insufficiency fracture. It was presumed that vaginal mucosa proximal to CTV received the total dose, with two patients developing vaginal ulcers, which both resolved; 10 patients reported mild telangiectasia, fibrosis, or stenosis.Conclusions: A review of patients treated with a customized vaginal mould and interstitial needles showed acceptable doses to CTV, with local control achieved in 67% of patients, and reasonable doses to organs at risk (OARs) and acceptable toxicity.