S72
Brachytherapy - Gynaecology
ESTRO 2026
Purpose/Objective: EMBRACE-II achieves excellent outcomes with image- guided-intensity-modulated-radiotherapy and image- guided-adaptive-brachytherapy1 in locally-advanced cervical cancer. Induction chemotherapy within INTERLACE2 improved survival using more historical radiotherapy techniques and its impact on modern brachytherapy delivery is uncertain. We aim to understand practice variation, induction chemotherapy uptake and its impact on brachytherapy delivery to understand consensus guidance priorities. Material/Methods: A 21 question survey was distributed to gynaecological radiotherapy healthcare professionals. Questions covered departmental details, brachytherapy technique, use/indications of induction chemotherapy, chemotherapy impact on brachytherapy delivery. Associations were assessed using chi-squared tests. Results: 72 responses from 24 countries were received, 51(71%) from Europe/9(12%) Australasia/8(11%) Asia/4(6%) Americas, 54(75%) from academic/university institutions. 16(22%) centres treat <20patients/year, 18(25%) >50. Average waiting times to start chemoradiation (without neoadjuvant treatment) are <2weeks in 16(22%)/2-4 weeks in 40(56%)/>4weeks in 16(22%). 7 centres(10%) deliver intracavitary only, 63(89%) intracavitary/interstitial, 1(1%) interstitial only. Anaesthetic is general only in 24(34%)/general and regional 24(34%)/regional only 20(28%). 23(32%) deliver outpatient treatment only/43(60%) inpatient only/6(8%) both. Dose fractionation is 3# in 15(22%), 4# in 35(52%), range in 16(24%), delivered using single insertion (7/16%), 2 insertions (18/41%) and >2 insertions (19/43%). 63(87%) use MRI at first fraction,32(45%) at second. All who do first fraction CT/MRI outline CTVHR, bladder, rectum. Amongst respondents, 18(25%) never use induction chemotherapy, 37(51%) use it in <20% of cases, 17(24%) >20%. No association was seen with country(p=0.393), waiting times(p=0.478) or brachytherapy technique(p=0.114). Indications include bulky primary disease (21/66%) or large nodal burden (21/66%). 10(18%) never experience brachytherapy deferrals from schedule, whereas 18(32%) experience deferrals rarely, 16(29%) sometimes, 11(20%) often, and 1(2%) always. In cases of thrombocytopenia, 14(20%) never defer, 30(43%) defer if platelets<50x109/l, 11(16%) if<20x109/l. For neutropenia 25(36%) never defer, 17(25%) defer with neutrophils<0.5x109/l, and 12(17%) if<1x109/l. 50%
implemented for routine interstitial HDR gynaecologic brachytherapy, achieving dosimetric precision equivalent to CT/MRI-based planning. Integration of PETRA-based catheter visualization and model-based applicator reconstruction enables accurate, registration-free MR-guided treatment planning, supporting a more efficient and patient-centered brachytherapy workflow in clinical practice. Keywords: MRI-only, PETRA, interstitial References: 1. Kaza E, Lee CY, King MT, Dyer MA, Cormack RA, Buzurovic I. First pointwise encoding time reduction with radial acquisition (PETRA) implementation for catheter detection in interstitial high-dose-rate (HDR) brachytherapy. Brachytherapy. 2022;21(4):501-510. doi:10.1016/j.brachy.2022.01.0032. Lee CY, Kaza E, Harris TC, et al. Catheter reconstruction and dosimetric verification of MRI-only treatment planning (MRTP) for interstitial HDR brachytherapy using PETRA sequence. Phys Med Biol. 2023;68(3). doi:10.1088/1361-6560/acaf48 An international survey on the impact of induction chemotherapy on current brachytherapy practice in locally advanced cervical cancer Gemma Eminowicz 1 , Supriya Chopra 2 , Bradley Pieters 3,4 , Monica Serban 5,6 , Remi Nout 7 , Maximilian Paul Schmid 8 , Umesh Mahantshetty 9 , Taran Paulsen Hellebust 10 , Peter Hoskin 11,12 , Kari Tanderup 13 1 Department of Oncology, University College London Hospital, London, United Kingdom. 2 ACTREC, Tata Memorial Centre, Navi Mumbai, India. 3 Department of Radiation Oncology, Amsterdam University Medical Centre, Amsterdam, Netherlands. 4 Cancer Treatment and Quality of Life, Cancer Centre Amsterdam, Amsterdam, Netherlands. 5 Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Canada. 6 Department of Radiation Oncology, University of Toronto, Toronto, Canada. 7 Department of Radiotherapy, Erasmus MC Cancer Institute, Rotterdam, Netherlands. 8 Department of Radiation Oncology, Medical University of Vienna, Vienna, Austria. 9 Tata Memorial Centre, Homi Bhabha National Institute,, Mumbai, India. 10 Department of Medical Physics, Oslo University Hospital, Oslo, Norway. Proffered Paper 3488 11 Department of Radiotherapy, Mount Vernon Cancer Centre, London, United Kingdom. 12 Division of cancer sciences, University of Manchester, Manchester, United Kingdom. 13 Department of Oncology, University of Aarhus, Aarhus, Denmark
who contour CTVIR when using induction chemotherapy do not reference imaging pre- chemotherapy.
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