ESTRO 2023 - Abstract Book

S310

Sunday 14 May 2023

ESTRO 2023

Materials and Methods In the study period combined spinal-epidural (CSE) anaesthesia was the preferred technique for applicator insertion. In the first 12 months this was supplemented with a general anaesthetic (GA), subsequently awake insertion was undertaken. The intrathecal component comprised 10 mg hyperbaric bupivacaine and 500 mcg diamorphine. Analgesia was maintained post- insertion with a continuous epidural infusion of 0.1% levobupivacaine and 2 mcg/ml fentanyl titrated to effect. Where regional anaesthesia was contraindicated GA was performed and post-insertion pain relief maintained with patient- controlled intravenous analgesia (PCA) using primarily oxycodone. Pain scores were recorded in recovery and at intervals post insertion. The total number of interventions by the pain team were noted. Other anaesthetists were encouraged to use a similar technique. Results 108 women underwent 121 insertions, 62% of procedures were anaesthetised by TC, the remainder were performed by 31 different senior anaesthetists, choice of technique was dependent on the anaesthetist’s personal choice/clinical situation. Pain scores are shown in Table 1. The highest pain scores were in those patients in whom a GA was used with no regional anaesthesia; pain scores improved with PCA. 46 insertions required no additional pain interventions in the postoperative period. 19 cases required 3 or more post-operative interventions above the routine acute pain daily ward round: 15 CSEs (18% of all CSEs performed), 3 epidurals (25%) and 1 spinal (7%).

Conclusion The CSE technique provides comparable analgesia to other forms of neuraxial block, reduces post-operative pain interventions compared to epidural analgesia alone. A positive unexpected consequence of this change in practice was the possibility for awake insertions which accelerated the recovery process, permitting more rapid delivery of the first fraction, improving safety by reducing the rate of out of hours treatment

PD-0408 Effects of simulated systematic applicator displacement in intra-cavitary HDR cervical brachytherapy O. Houlihan 1,2 , M. Byrne 3 , O. McLaughlin 3,4 , G. Workman 3 , S. Esteve 3 , U. McGivern 1 , A. Drake 1 , E. Baird 1 , K. Prise 2 , A. Hounsell 3 , S. Jain 1,2 1 Northern Ireland Cancer Centre, Belfast Health and Social Care Trust, Clinical Oncology, Belfast, United Kingdom; 2 Queen's University Belfast, Patrick G. Johnston Centre for Cancer Research, Belfast, United Kingdom; 3 Northern Ireland Cancer Centre, Belfast Health and Social Care Trust, Radiotherapy Medical Physics, Belfast, United Kingdom; 4 Patrick G. Johnston Centre for Cancer Research, Queen's University Belfast, Belfast, United Kingdom Purpose or Objective To simulate systematic applicator displacements in intra-cavitary HDR cervical brachytherapy with the view to determining the required accuracy of in vivo dosimeters developed as part of the EU H2020 ORIGIN project. Materials and Methods 20 CTs performed prior to the first fraction of intra-cavitary HDR cervical brachytherapy were included. Organs at risk of interest were bladder, rectum and bowel. The bladder and rectum were divided into subsections of superior, middle and inferior along divisions of the upper, middle and lower third of the high risk clinical target volume (HRCTV)(Fig. 1). The ring and tandem applicator was systematically displaced in 1 mm increments from 1-6 mm in cranial, caudal, anterior, posterior, left and right directions along the plane of the central tandem to simulate applicator displacement between planning CT and brachytherapy delivery. The D2cc (minimum dose to the most irradiation 2cc) was calculated for each displacement and compared to the original planning CT.