Multicenter prospective randomized controlled trial of comparing laparoscopic proximal gastrectomy and laparoscopic total gastrectomy for upper third early gastric cancer (KLASS-05).

TPS184 Background: Proximal gastrectomy (PG) is rarely performed for upper third early gastric cancer (EGC) because of postoperative reflux esophagitis. Recently, PG with double tract reconstruction was introduced and reported to have a reflux of approximately the same frequency as total gastrectomy (TG) with esophagojejunostomy. PG has several theoretical advantages over TG but has not yet been proven in randomized controlled trial. This study aimed to provide scientific evidence of laparoscopic PG with double tract reconstruction as a standard procedure for proximal EGC. Methods: The present trial is multicenter, prospective, randomized, controlled trial with superiority design. A total of 138 patients with upper third cT1N0M0 gastric adenocarcinoma are randomized to laparoscopic PG with double tract reconstruction and laparoscopic TG with esophagojejunostomy. Patients are enrolled for two years and followed up for two years. Primary co-endpoints are hemoglobin change and vitamin B12 cumulative supplement quantity after 2 years of operation. We used the alpha-split method to set the hemoglobin to 4% and vitamin B12 to 1% for alpha. The sample size needed was 62 patients for each arm. Accounting for 10% follow-up loss, the enrollment of 69 patients in each group was required. Secondary endpoints are prevalence rate of postoperative reflux esophagitis, morbidity and mortality, quality of life 2-year after operations, relapse-free survival, and overall survival. Nineteen investigators from 10 institutes participated in this trial. The first patient was enrolled on October 27, 2016 and we completed the patient enrollment on September 17, 2018. Clinical trial information: NCT02892643.