MRI-guided brachytherapy for locally advanced cervical cancer: Program initiation, learning curve and dose delivery results in Kuopio University Hospital

BACKGROUND AND PURPOSE: Image guided adaptive brachytherapy, the standard treatment for locally advanced cervical cancer (LACC), is a complex medical procedure that requires an experienced multidisciplinary team. The aims of this analysis were to assess (1) the learning curve of brachytherapy team, (2) dose-volume parameters, (3) the use of an interstitial component, and (4) the overall treatment time (OTT). MATERIALS AND METHODS: Our study cohort comprised 117 LACC patients treated in Kuopio University Hospital with magnetic resonance imaging guided intracavitary (IC) or combined intracavitary/interstitial (IC/IS) high dose rate brachytherapy during 2009-2018. Target volumes and organs at risk (OAR) were contoured according to ICRU/GEC-ESTRO recommendations. Treatment plans were optimized individually without using standard loading patterns. RESULTS: Mean dose to 90% of the high-risk clinical target volume (HR-CTV D90) improved after the first 15 patients, however the team's learning curve to reliably fulfill the main planning aim (PA) of 85 Gy required a total 43 patients and more than 10 patients annually. Significant difference was detected between IC and IC/IS brachytherapy in achieving the PA of HR-CTV D90. Especially, HR-CTV volumes > 30 cm(3) benefitted from IS needles. Needle insertion did not cause serious complications. With the brachytherapy program, the OTT of patients from outside institutions was reduced to the same level as our own patients. CONCLUSION: Brachytherapy requires good experience of multidisciplinary team and the continuous development of the program to fulfill PA and to avoid OTT prolongation. The use of IS needles is safe and improves the fulfillment of PA to target volume. (c) 2021 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.