Reirradiation for recurrent gynecologic cancer using high-dose-rate brachytherapy in Japan: A multicenter survey on practice patterns and outcomes

Background and purpose The aim of the study is to examine the present status of reirradiation with high-dose-rate (HDR) brachytherapy for recurrent gynecologic cancer in Japan and to determine the role of this therapy in clinical practice. Materials and methods A retrospective multicenter chart review was performed for reirradiation for gynecologic cancer using HDR brachytherapy. Each center provided information on patient characteristics, treatment outcomes, and complications. Results The study included 165 patients treated at 9 facilities from 2000 to 2018. The analysis of outcomes included 142 patients treated with curative intent. The median follow-up time for survivors was 30 months (range 1–130 months). The 3-year overall survival (OS), progression-free survival (PFS), and local control (LC) rates were 53 % (95 %CI: 42–63 %), 44 % (35–53 %), and 61 % (50–70 %) for cervical cancer; 100 % (NA), 64 % (30–85 %), and 70 % (32–89 %) for endometrial cancer; and 54 % (13–83 %), 38 % (6–72 %), and 43 % (6–78 %) for vulvar and vaginal cancer, respectively. In multivariate analysis, interval to reirradiation (<1 year) was a significant risk factor for OS, PFS and LC; Gross Tumor Volume (≥25 cm3) was a significant risk factor for OS. Toxicities were analyzed in all enrolled patients (n = 165). Grade ≥ 3 late toxicities occurred in 49 patients (30 %). A higher cumulative EQD2 (α/β = 3) was significantly associated with severe complications. Conclusion Reirradiation with HDR brachytherapy for recurrent gynecologic cancer is effective, especially in cases with a long interval before reirradiation.