Prelude to a registration study on CT based IGABT for cervical cancer: An international survey
PO-2145
Abstract
Prelude to a registration study on CT based IGABT for cervical cancer: An international survey
Authors: RAVITEJA MIRIYALA1, Max Schmid2, Christian Kirisits2, Primoz Petric3, Umesh Mahantshetty1
1Homi Bhabha Cancer Hospital and Research Centre, Department of Radiation Oncology, Visakhapatnam, India; 2Medical University of Vienna, Department of Radiation Oncology, Vienna, Austria; 3University Hospital Zürich, Department of Radiation Oncology, Zürich, Switzerland
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Purpose or Objective
MRI based brachytherapy (BT) is considered standard for IGABT in cervical cancer, with excellent local control rates of over 90% at 5 years. However, access to MRI with brachytherapy applicator in-situ is limited in many high-volume centres across the globe. Recently, recommendations for target volume delineation in CT based IGABT have been published by IBS-ESTRO-ASTRO. A prospective international registration study is being planned to benchmark clinical outcomes of cervical cancer treated with CT based IGABT. To identify the need and interest in various CT based environments that can be potentially included in the protocol, a survey was conducted among selected centres with prior experience in IGABT.
Material and Methods
The survey questionnaire was designed to estimate feasibility of implementing CT based IGABT with or without additional modalities like pre-BT MRI or Transrectal ultrasound (TRUS), in a multicentre setting. CT based planning for EBRT and BT, access to CT compatible hybrid IC+IS applicators, and prior experience with IGABT were considered pre-requisites for participation.
Results
Of the 28 centres that were approached, 20 centres from 7 countries (India, Egypt, Botswana, Brazil, Thailand, Singapore and Indonesia) responded and expressed interest to participate in a CT based IGABT registration study. Access to diagnostic MRI was reported by 80% of centres. IG-IMRT is routinely used for EBRT in 80% of centres. 85% reported feasibility of using pre-BT MRI in addition to CT based IGABT. While 60% centres have access to TRUS, only 20% have prior experience using TRUS for target definition and treatment planning. 70% centres reported use of IC+IS BT in >10% of cases. Confidence in target volume delineation on CT alone was reported to be high in 65% centres and moderate in 35% centres. Confidence in dose prescription to CT based target volumes was reported to be higher for IC alone (95% centres) compared to IC+IS (75% centres).
Conclusion
Results of our survey indicate that there is a significant interest among the centres in CT based IGABT registration study. It appears feasible to incorporate pre-BT MR and TRUS environments apart from CT alone environment in the registration study. There is a potential need for additional training in target delineation and treatment planning with CT based IGABT, especially with incorporation of TRUS.