Novel endoscopic imaging and technology for the diagnosis and management of early gastrointestinal neoplasia

Student thesis: Doctoral Thesis

Abstract

The changing landscape of endoscopy over the past decade has seen it evolve from a purely diagnostic instrument to an exciting tool for therapy. It is the main mode of diagnosis of early neoplasia in both the upper and lower gastrointestinal tract where recent advances in chromoendoscopy and electronic image enhanced endoscopy can facilitate earlier detection of cancer. Identifying and characterising neoplasia accurately at an early stage enables the use of minimally invasive endoscopic resection techniques to remove these cancers with curative intent, thereby avoiding surgery with its associated morbidity and mortality. In the introductory chapters, we will review the common types of gastrointestinal cancers and their precursors (with a focus on Barrett's oesophagus and colorectal polyps) as well as the evidence for the various dye-based (chromo) and advanced imaging endoscopic technologies that can improve the detection and characterisation of early neoplasia in the oesophagus and colon. We will also review the endoscopic resection techniques in use for removal of oesophageal and colonic pre-cancerous or early cancerous lesions and discuss the management of common complications associated with these resection techniques. In Chapter 4, we describe a prospective image evaluation study using Blue Light Imaging for the optical diagnosis of small colorectal polyps. We studied the baseline performance of two groups of endoscopists (experienced and trainees) in optical diagnosis of colorectal polyps and then designed and implemented a training module using a bespoke classification in both groups. Baseline performance of both groups was similar, and both improved significantly when trained to use a bespoke classification to distinguish between adenomatous and hyperplastic colorectal polyps. Chapter 5 presents the development and validation of a new classification system for identification of neoplastic and non-neoplastic areas within Barrett's oesophagus using Blue Light Imaging. We demonstrated that this unique classification could be used effectively by general endoscopists (after undergoing training) with a high level of sensitivity and negative predictive value for neoplasia achieved. Chapter 6 describes the use of endoscopic submucosal dissection as a new technique for removal of complex early Barrett's cancers. This was studied in a retrospective international multi-centre cohort study involving 124 patients. The technique was shown to be safe, effective and useful in removing lesions that were large (>2cm), scarred or submucosally invasive. In Chapter 7, we evaluate the safety and efficacy of radiofrequency ablation in a retrospective cohort study of 91 patients encompassing 3 groups (either following endoscopic mucosal resection, endoscopic submucosal dissection or with no previous resection). There was no significant increase in the complication rate when radiofrequency ablation was used following endoscopic submucosal dissection. Chapters 8 and 9 describe 2 studies on the use of a novel self-assembling peptide as an endoscopic haemostatic agent. The first study (Chapter 8), is a descriptive cohort study on a group of 100 patients undergoing endoscopic resection where the haemostat was used either prophylactically to prevent delayed bleeding or to stop intraprocedural bleeding. This showed that it was feasible to use under these circumstances. Chapter 9 describes a randomised controlled trial of 100 patients where the haemostat or conventional therapy (heat) was used to stop bleeding. The trial showed that the haemostat was effective in reducing the need for diathermy to stop intraprocedural bleeding with no additional complications and no increase in delayed bleeding. Finally, the thesis concludes with a summary in Chapter 10 forming the basis of the direction for future travel in endoscopy research arising from the findings of this body of work.
Date of AwardJan 2021
Original languageEnglish
SupervisorPradeep Bhandari (Supervisor) & James Brown (Supervisor)

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