Optimising outcomes of endoscopic resection of neoplastic gastrointestinal lesions

Abstract

Barrett’s oesophagus (BE), a known complication of gastroesophageal reflux disease, is characterised replacement of the squamous lining of the distal esophagus by columnar epithelium containing specialized intestinal metaplasia (IM). BE is the only known precursor to oesophageal adenocarcinoma (EAC). EAC incidence has outstripped all other solid organ malignancy and increased almost 6-fold over the past 3 decades 1 2. It has a survival rate of less than 20% at 5 years 3. Most people with BE never develop EAC and most patients diagnosed with EAC have no preceding diagnosis of BE. Progression from BE to EAC occurs in a stepwise manner based on the degree of dysplasia, which is the best marker for predicting progression in patients with BE 4. Histologic progression is noted in a predictable manner starting with low-grade dysplasia (LGD), followed by high-grade dysplasia (HGD), and lastly EAC (superficial or invasive). Superficial EAC comprises the histological tumour classification of T1a (invasion into the mucosa; also known as intramucosal cancer (IMC)) and T1b (invasion into the submucosal but not the muscularis propria) 5. HGD and IMC are often grouped together as Barrett’s Early Neoplasia (BEN). The progression of non-dysplastic BE to BEN ranges from 1.2 to 3.3 per 1000 patient years 6 7. The incidence rate of BEN was 13.4% per patient per year for patients in whom the diagnosis of LGD was confirmed by an academic centre histopathologist 8. This pathologic stepwise progression provides an opportunity for early intervention to prevent development of EAC or eradicate EAC, and thus avoid morbidity and mortality related to this lethal cancer. Endoscopic eradication therapy (EET) for patients at increased risk of progression to EACis endorsed by multiple gastroenterological society guidelines 9-11. Given its efficacy and safety profile, EET as a first line therapy for BEN has ever increasingly replaced oesophagectomy, which has a 30 day mortality of up to 6% 12. The rationale for oesophagectomy for BEN is the concern for synchronous occult invasive carcinoma, which in the surgical series is between 8% and 12% 13-15. Systemic review data of 1350 EAC cases that underwent oesophagectomy noted lymph node metastasis in 1.9% of IMC cases [95% confidence interval (CI), 1.1%-2.6%] and 0% in HGD cases. Considering that the risk of lymph node metastasis in T1a disease is similar or lower than the mortality of oesophagectomy, even at high-volume centers, there is a convincing argument for EET. The management paradigm of BEN centers around resection of all visible lesions which are usually harbingers of the highest grade of dysplasia and subsequent BE eradication of the remaining BE to reduce the risk of metachronous neoplasia (up to 30%) 16. Subsequently patients are enrolled into a surveillance program to identify and treat any possible recurrent neoplasia. Complete BE eradication (CBE) can be achieved through endoscopic resection (ER), endoscopic ablation (EA) or a combination of the two approaches (hybrid therapy). Endoscopic resection can be achieved by endoscopic mucosal resection (EMR) or endoscopic submucosal dissection (ESD). EA techniques include radiofrequency ablation (RFA), cryotherapy or photodynamic therapy. The most common practiced EET modalities are EMR and RFA.