The Use of Biomarkers to Guide Management of Patients Treated With Radiofrequency Ablation for Early Oesophageal Neoplasia

The Cytosponge will be administered by the study nurse prior to the participant having the endoscopy, usually as part of the same visit to hospital. The capsule along with the string is swallowed by drinking a small glass of water. The participant is asked to hold the Cytosponge in situ for 5 minutes. The sponge contained within expands and is then drawn back by the research nurse up the oesophagus by the attached string, collecting cells as it moves upwards. This device received a letter of no objection by the MHRA for use in the BEST pilot trial (LRQ 0939857) but it is not CE marked. Cytosponge and research endoscopic biopsies will be couriered to the Fitzgerald laboratory, at the MRC Cancer Cell Unit on a regular basis. The specimens will be processed in conjunction with the Cambridge University Hospitals' NHS Foundation Trust tissue bank which is accredited to GLP standards.

Molecular analysis of the specimen obtained by Cytosponge or endoscopic biopsies - TFF3 protein expression, methylation panel, p53 mutation. Endoscopic biopsies will be assessed for the presence of IM (according to the IM-score).

"* Endoscopy will be carried out with white light and NBI with optical magnification or near focus to inspect oesophagus and GOJ.~* NBI magnification will be used to assess systematically the mucosal pit pattern at the GOJ and to look for light blue crest (LBC) sign.~* Targeted biopsies will be taken from either areas with LBC or irregular pit pattern on NBI, followed by random biopsies as per clinical standard. A maximum of 6 biopsies will be taken at the GOJ (maximum 4 targeted and 4 random.. During the first 2 post RFA follow up, at discretion of the endoscopists, neo-suqamous biopsies can be taken in line with local policies.~* Argon plasma coagulation ablation is allowed in a single island up to 5mm or up to 3 islands \<3mm within the study endoscopy as long as this does not represent an obstacle to GOJ biopsies."