Clinical outcomes of patients treated with template-based high-dose-rate interstitial brachytherapy boost for post-operative recurrent gynecological malignancies: A retrospective analysis

Purpose To report the clinical outcomes in patients treated with Martinez universal perineal interstitial template (MUPIT)-based interstitial brachytherapy boost for primary and recurrent vault and vaginal cancers, and to perform a comparative analysis with our previously published series of similar patients. Material and methods One hundred and seventeen patients treated between January, 2009 and December, 2015 were evaluated. Descriptive statistics for the patterns of relapse, local recurrence-free survival (LRFS), disease-free survival (DFS), overall survival (OS), and late toxicities were carried out. Kaplan-Meier curves were used for survival analysis. All variables with the potential to affect outcomes were tested using log-rank test for statistical significance. Results At a median follow-up of 63 months, LRFS, DFS, and OS at 3/5 years were 77.1%/74.7%, 61%/52%, and 72.3%/63.1%, respectively. Overall treatment time (OTT) of 56 days did not affect outcomes. Bulky tumors and OTT > 63 days adversely affected LRFS. Overall treatment time also significantly impacted DFS and OS. Grade 3-4 late bladder toxicities were observed in 1.7% patients, and grade 3-4 late rectal toxicities in 5% patients. Compared to our previous series, the outcome in the current series is better in terms of severe late toxicities (5% improvement in rectal toxicity, and 2.7% improvement in bladder toxicity) and OS by 10%. This could be attributed to the increasing use of concurrent chemotherapy and relative optimization strategies for organs at risk. Conclusions Patients with primary and recurrent vault and vaginal cancers treated with high-dose-rate interstitial brachytherapy boost using MUPIT resulted in modest clinical outcomes and acceptable late toxicities. OTT was the most important factor affecting the outcomes.