Both sulfate supplements and changes in intestinal transit rate markedly alter the activity of the colonic bacterial flora with respect to sulfate metabolism and hydrogen disposal. Dietary influences on intestinal transit and sulfate consumption may influence disease processes. While a variety of processes govern sulfate metabolism and hydrogen disposal, our knowledge is far from complete. How far the observed changes in sulfate metabolism seen in certain diseases are relevant to the pathogenesis of the disease or secondary to the disease itself is unclear.

SUMMARYBackground Nitrous oxide gas (N 2 O) has been proposed as an alternative to intravenous (i.v.) analgesia in patients undergoing lower gastrointestinal endoscopy.

IntroductionEndoscopic resection and ablation treatment is the standard of care for barretts oesophagus and related early neoplasia. To evaluate the real world experience with EMR and RFA treatment at a single centre outside of clinical trials.MethodData was evaluated from a prospectively maintain charts of patients undergoing RFA/EMR treatment for Barretts and Early Oesophageal Cancer (EOC) (T1a and T1b). All patients with Barretts dysplasia referred through MDT from 2010–2015 were included in the study.ResultsA total of 91 patients The mean age of the patients undergoing RFA/EMR is 72±8, (Range: 47–92) years with predominance of male population (85%). The most common reason for referral was HGD (58%) followed by LGD (17%), T1a (16%), T1b (7%) and squamous dysplasia (2 and ).EMR was performed in in 75/91 (82%) patients in the study mostly in OEC patients (100%) followed by HGD (78%) and LGD (45%) patients. The disease was upstaged in 20% of study patients with 12 patients referred with HGD upstaged to T1a and 3 patients to T1b. Upstaging to HGD was observed in 3 patients with LGD. Only 3 patients had their disease down staged (x2: T1a to HGD and x1: HGD to LGD).RFA was performed in majority of the patients in our study (86.4%, n=76) with median RFA sessions of 2 (Range:1–6). The proportion of patients having RFA performed with final diagnosis of LGD, HGD, T1a and T1b was 92%, 95% and 91% and 30% respectively.A complete response (CR) defined as complete endoscopic and histological eradication of barretts oesophagus after HALO procedure was seen in 88% patients who completed the study (n=68). The excluded patients included those who did not opt for further RFA (n=6) sessions and patients which died of unrelated deaths (n=2). The CR is 100% in patients with LGD and T1a and 79% in HGD group.Out of 9 patients with T1b cancer, 7 had oesophagectomy done with none of the patient having cancer in resected specimen or had disease recurrence including 1 patient who had T1N1 cancer. CR was mostly seen in patients with prior EMR than who did not (79% vs. 21%). In all the non-CR (n=6), 80% had Barretts>6 cms and 100% of incomplete responders had HGD.Nine patients (10%) had complications from HALO procedure with 6 patients requiring endoscopic dilatation of post RFA oesophageal stricture after CR and 2 having ulceration at previous RFA site precluding further RFA. Post RFA stricture was seen mostly in LGD patients than in HGD patients (23% vs. 5%) and 80% of these patients had a prior EMR. 1 patient had a suspected oesophageal perforation after a rescue EMR which was successfully sealed by OVESCO clip. There was no procedure related deaths.ConclusionRFA is a safe and effective procedure for management of early oesophageal neoplasia.Disclosure of InterestNone Declared