P229 A novel approach to radiotherapy targeting for oesophageal squamous-cell cancer using lugol’s-solution guided endoclip marking

IntroductionSquamous cell carcinoma (SCC) of the oesophagus often presents at a late stage with dysphagia symptoms. Chemoradiation (definitive or neoadjuvant treatment) remains the standard strategy for the treatment of localised SCC. Accurate radiotherapy target delineation is however problematic for very early tumours that cannot be visualised on cross-sectional imaging. We describe a novel technique of endoscopic clip placement to mark the area for targeted radiotherapy, in conjunction with Lugol’s iodine chromoendoscopy to delineate the dysplastic field.MethodsA prospective study of procedures performed using the technique between 2017 and 2020 was undertaken in a tertiary referral centre. Unstained lesions (USL) were described and photographed, The proximal and distal extent of USLs were marked with ResolutionTM endoclips (Boston Scientific) which were placed on normal appearing squamous tissue 0.5 cm away from the USL. Four operators carried out the procedures with expertise in Endoscopic Eradication therapy and lesion recognition. Endoscopy reports, clinic letters, and imaging modalities were all interrogated to evaluate patient outcomes.ResultsFifteen patients were enrolled, 4 male, 11 female. Thirteen (86.7%) were for a new diagnosis of SCC, and 2 (13.3%) were for SCC recurrence. All patients were staged as T2N0M0 on CT. Eight patients had prior EUS and 13 had PET-CT scans, but these imaging modalities could only detect the area of abnormality in 3 (20%), and 4 (26.7%) of cases respectively.Lugol’s Chromoendoscopy was able to clearly delineate the dysplasia in all cases (100%). The mean total length of oesophageal USL marked with clips was 7.3 cm ± 3.8. The mean length of endoscopic procedure was 9.2 minutes ± 2.4. All procedures were undertaken with conscious sedation with a median dose of 2.5 mg midazolam (2.5–3.0) and 50 mcg fentanyl (0–75 mcg). All 15 patients scored comfortable on a GRS scale. Mean time from clip deployment to CT radiotherapy planning scan was 7.8 days (± 5.1). No clips fell off prematurely requiring repeat endoscopy. Median dose of radiotherapy delivered was 50Gy. At 12-months, of those followed up 26.7% had evidence of relapse free survival.ConclusionsHere we describe a novel technique using Lugol’s guided clip placement prior to radiotherapy, demonstrating it to be a quick and uncomplicated procedure which can be used in the management of patients with SCC.