Session Item

Rationale  
The GEC-ESTRO recommendations and ICRU 89 developed a comprehensive methodology for unified target and organs at risk (OAR) contouring and for using a common language in dose prescribing and reporting based on the equi-effective dose concept in locally advanced cervical cancer. The ICRU 89 report meets different environments of resources and clinical practice by defining basic and advanced levels of prescribing, recording and reporting.  Currently, a number of clinical approaches are being applied all over the world with regard to applicators, treatment planning, and dose and fractionation in cervix cancer brachytherapy. Until recently there was no strong evidence available for preferring one clinical approach to another. With the dissemination and adoption of the joint principles of 3D image-guided brachytherapy, there are more opportunities to compare techniques, dose administration and clinical outcomes across patients and institutions. Clinical evidence correlating dose-volume parameters and clinical outcomes has been established for an increasing number of clinical endpoints including targets and OARs. For the purpose of providing international recommendations for brachytherapy treatment planning based on evidence, an interdisciplinary group has been established with representatives from Groupe Européen de Curiethérapie and European SocieTy for Radiotherapy Oncology (GEC-ESTRO), Indian Brachytherapy Society (IBS) and American Brachytherapy Society (ABS). The work of the group will be ongoing throughout 2020 and the recommendations are expected to be published in 2021. This abstract outlines the purpose and contents of the upcoming GEC-ESTRO/IBS/ABS brachytherapy treatment planning recommendations in locally advanced cervical cancer.  
Purpose
To provide clinical and physics evidence-based guidelines for treatment planning in cervix cancer brachytherapy using the methodology (concepts and terms) as outlined in GEC-ESTRO recommendations (I-IV) and the ICRU report 89. To define various clinical-radiological environments according to variable clinical resource availability. To describe the impact that the disparate environments have on treatment planning and performance of appropriate cervix cancer brachytherapy. To define practical treatment planning approaches which take into account the various basic and advanced levels of clinical-radiological environments. The recommendations will cover treatment planning based on MRI with applicator in place as the gold standard, as well as alternative infrastructures where clinical examination together with combinations of CT, ultrasound, and 2D x-ray imaging are applied. To enable centers with different levels of clinical experience to perform treatment planning in cervix cancer brachytherapy appropriately according to tumour extension and topography to maximize chance of cure while minimizing morbidity within the context of a particular center’s environment and resources.    
Outline of topics  
Brachytherapy treatment planning in locally advanced cervical cancer is not an isolated process limited to performance of brachytherapy, but involves the entire radiotherapy planning workflow including diagnostic imaging and external beam radiotherapy (EBRT) treatment planning. The brachytherapy treatment planning recommendations provided in this recommendation broadly cover considerations of imaging and clinical examination at time of diagnosis and brachytherapy as well as important factors for high quality brachytherapy treatment planning. The recommendations are based on clinical and technical evidence whenever this is available. Furthermore, other international guidelines will be considered to collect and evaluate different approaches (e.g. ABS, IBS, JASTRO).
- Evidence for correlations between dose/volume and clinical outcome as well as between brachytherapy technique and dosimetric outcome (tumor, OARs)
- Description of different clinical-radiological environments for imaging (diagnostic and during radiotherapy) and performance of brachytherapy as well as uncertainties related to imaging modalities and combinations of imaging
- Process of treatment planning and performance of brachytherapy: description and definition of the steps of treatment planning including pre-implantation preliminary treatment planning and applicator selection
- Practical approaches for planning and performing appropriate brachytherapy within different clinical-radiological environments to arrive at the best possible chance of cure within the given practical frame of basic or advanced technology as available in the various treatment centers:
o   Dose planning aims and dose prescription protocols
o   Dose optimization, loading patterns and conformality
o   Dose and fractionation