Cesium-131 Low-Dose Rate Interstitial Brachytherapy as a Salvage Re-Irradiation Technique in Treating Cervical and Uterine Cancer Pelvic Recurrence with Prior History of Pelvic Radiation

Abstract

Pelvic recurrence among cervical and uterine cancer patients with prior history of pelvic radiation is a poor prognostic factor and remains challenging. The standard of care is pelvic exenteration, which is a highly morbid surgical procedure. The purpose of this study is to report local control rate and toxicity profile of Cesium-131 low-dose rate interstitial brachytherapy (LDR) as a salvage re-irradiation technique in managing pelvic relapse. We reviewed procedures and outcomes from patients with previously irradiated uterine corpus or cervix neoplasms, who subsequently relapsed and then underwent cesium-131 LDR implants between January 2016 and December 2022. Patient demographics, treatment planning variables, and disease response were reviewed. Acute toxicities, late toxicities, and local control rate were compiled for this study. A total of 12 eligible patients (6 cervical and 6 uterine cancer) with 16 cesium-131 LDR implants were included in this study. The majority (75%) of pelvic relapses occurred at the exocervix (cervix-intact) or vaginal cuff (post-hysterectomy). Median time from disease relapse to cesium implant was 32 days. The average area of implementation was 9 cm2 and average number of seeds implanted was 16. The mean prescription dose was 50 Gy. Six patients also received high-dose rate vaginal intracavitary brachytherapy in addition to cesium-131 LDR. Median follow up was 12 months. 81% of cesium implants achieved complete response at first post-treatment follow-up, while the remaining 19% demonstrated partial response. The 6-months local control rate was 79%. After cesium implant, 25% patients had local recurrence and 33% with distal metastasis. The most reported acute toxicities included vaginal mucositis (63%), dysuria (50%) and pain (19%). All patients had various degrees of vaginal stenosis and strictures long-term. Only 1 (8%) out of 12 patients, with 4 repeated cesium-131 LDR implants, developed a rectovaginal fistula and chronic pain. Cesium-131 LDR interstitial brachytherapy is a safe and feasible salvage re-irradiation technique in treating pelvic relapse among uterine corpus or cervix cancer patients with prior history of pelvic radiation. Local control rate at 6-months was acceptable with minimum toxicity. Long-term follow up is warranted to validate the efficacy of cesium-131 LDR. We conclude that cesium-131 LDR interstitial brachytherapy is a promising alternative to pelvic exenteration in selective patient population. Future prospective study is warranted.