MR- versus CT-based high-dose-rate interstitial brachytherapy for vaginal recurrence of endometrial cancer

Abstract

Purpose To compare clinical outcomes of MR-based versus CT-based high-dose-rate (HDR) interstitial brachytherapy (ISBT) for vaginal recurrence of endometrioid endometrial cancer (EC). Methods We reviewed 66 patients with vaginal recurrent EC; 18 had MR-based ISBT on a prospective clinical trial and 48 had CT-based treatment. Kaplan-Meier (K-M) survival modeling was used to generate estimates for local control (LC), disease-free interval (DFI), and overall survival (OS) and multivariate Cox modeling was used to assess prognostic factors. Toxicities were evaluated and compared. Results Median follow up was 33 months (CT 30 months, MR 35 months). Median cumulative EQD2 was 75.5 Gy for MR-ISBT and 73.8 Gy for CT-ISBT (p=0.58). MR patients were older (p=0.03) and had larger tumor size (>4cm vs ≤4cm) compared to CT patients (p=0.04). For MR- vs. CT-based ISBT, 3-year KM rate for LC was 100% vs. 78% (p = 0.04), DFI was 69% vs. 55% (p= 0.1), and OS was 63% vs. 75% (p= 0.81), respectively. On multivariate analysis, tumor grade 3 was associated with worse OS (HR 3.57, 95%CI 1.25,11.36) in a model with MR-ISBT (HR=0.56, 95%CI 0.16,1.89). Toxicities were not significantly different between the two modalities. Conclusion Despite worse patient prognostic features, MR-ISBT was associated with a significantly better (100%) 3-year local control, comparable survival, and improved DFI rates compared to CT. Toxicities did not differ compared to CT-ISBT patients. Tumor grade contributed as the most significant predictor for survival. Larger prospective studies are needed to assess the impact of MR-ISBT on survival outcomes.

Salvage Re-irradiation With Single-modality Interstitial Brachytherapy for the Treatment of Recurrent Gynaecological Tumours in the Pelvis: A Multi-institutional Study

“…The 3year local control rate was 71% in patients with previous radiation in the study by Kamran et al [20]. This study reports an overall survival rate of 78% at 2 years but only 38% at 3 years, which is initially higher than previously reported 2-year overall survival rates of 52.5, 67, 52 and 61% [16,19,22,25], but lower than the reported 3year overall survival rate of 54% by Kamran et al [20]. This might be due to inherent limitations in our study, including heterogeneity in patient inclusion and selection bias, as well as a median follow-up of just 2 years.…”

Clinical implementation, logistics and workflow guide for MRI image based interstitial HDR brachytherapy for gynecological cancers

“…Several studies have evaluated the best MRI sequences for gynecological brachytherapy . The MRI sequences used for our brachytherapy procedure follow the GEC‐ESTRO recommendations with some modifications based on input of diagnostic radiologists at our institution (see below for all sequences).…”

ESGO/ESTRO/ESP guidelines for the management of patients with endometrial carcinoma

“…Locoregional recurrence of endometrial carcinoma is rare. With the advent of modern image guided radiation therapy, including IMRT and image-guided adaptive brachytherapy, radiotherapy has become the treatment of choice in previously not-irradiated patients with isolated vaginal recurrence or locoregional recurrence [362,363,[369][370][371][372][373][374][375][376][377][378]. Consideration should be given to remove solitary, easily accessible vaginal relapses, for better local symptom control prior to radiotherapy.…”

“…Otherwise, further radiation should be considered as radical therapy with or without systemic therapy. Interstitial brachytherapy (low-dose rate or highdose rate) as sole modality of treatment or combined with EBRT can result in high local control over 1-5 years [373,374,381,382]. Other techniques like permanent seed implant or post-operative electron irradiation, protons and stereotactic body radiotherapy may be reccommended in highly selected patients [383][384][385].…”