Cytosponge™ for post‐chemoradiation surveillance of oesophageal cancer: a feasibility study

Introduction: Definitive chemoradiotherapy (dCRT) is a less invasive treatment option in oesophageal cancer compared with surgery, but it has a higher incidence of local recurrence. If detected early, local recurrence can be salvaged through surgery. Regular endoscopic surveillance can be used to assess for recurrence, but it is invasive and costly. It has been demonstrated that the entire clonal architecture of a dysplastic oesophagus delineated from multiple biopsies was captured by a single device; the Cytosponge™ [1]. The feasibility and acceptability of the Cytosponge™ as a tool for detection of Barrett’s oesophagus (in non‐cancer patients) has been tested in over 2000 patients including a primary care study of 504 patients and a secondary care case-control study of 1100 patients [2, 3]. The procedure is safe in patients with Barrett’s oesophagus but has not been prospectively tested in patients with cancer. The Cytosponge™ study (NCT03529669) will investigate the feasibility of the Cytosponge™, as a less invasive technique, in post-CRT surveillance in oesophageal cancer. Methods: This is a feasibility study that is recruiting patients with known oesophageal cancer treated with preoperative or definitive chemoradiation. All participants will receive the Cytosponge™ test at one time‐point within 4-16 weeks after completion of preoperative or definitive CRT. The Cytosponge™, which is swallowed and retrieved after 5 minutes, consists of an expandable spherical mesh encapsulated in a gelatine capsule attached to a cord. Telephone follow-ups occur one and two weeks after the procedure. The primary objective is to ascertain the proportion of evaluable patients successfully undergoing the Cytosponge™ procedure. The safety and acceptability of the procedure (consent rate and percentage who would be willing to accept the procedure repeatedly) will also be determined. All reported adverse events are recorded. Fifty patients will be recruited from 11 sites in the UK. Recruitment is on target and is one-third complete. The Cytosponge™ will be processed for evidence of residual cancer through analysis of cellular atypia and molecular biomarkers. Where available, the results will be compared with histology. Sponsor: University of Oxford Funding source: CRUK [C28958/A22173] Cytosponge™ provided by Cambridge University Hospitals NHS Foundation Trust