Short‐Term Outcomes from a Randomized Screening Phase II Non‐inferiority Trial Comparing Omentectomy and Omentum Preservation for Locally Advanced Gastric Cancer: the TOP‐G Trial

Abstract

Background Omentectomy is considered an essential part of curative gastrectomy for locally advanced gastric cancer (GC), albeit without solid evidence. We conducted a randomized phase II trial (the TOP-G trial) comparing omentectomy and omentum preservation for gastric cancer. This report describes the short-term findings regarding the trial's secondary endpoints. Methods The trial protocol was submitted to the University Hospital Medical Information Network Clinical Trials Registry (http://www.umin.ac.jp/ctr/: UMIN000005421). The key eligibility criteria were histologically confirmed cT2-4a and N0-2 gastric adenocarcinoma. Short-term surgical outcomes, including morbidity and mortality, were compared between the omentectomy group (group A, control arm) and the omentum-preserving surgery group (group B, test arm). All procedures were performed via an open approach. Based on a non-inferiority margin of 7%, statistical power of 0.7, and type I error of 0.2, the sample size was set to 250 patients. Results A total of 251 patients were eligible and randomized (group A: 125 patients, group B: 126 patients) between April 2011 and October 2018. After excluding patients who had peritoneal metastasis or laparotomy history, safety outcomes were analyzed for 247 patients. Group A had a significantly longer median operation time (225 min vs. 204 min, p = 0.022) and tended to have greater median blood loss (260 mL vs. 210 mL p = 0.073). The incidences of morbidity were similar and \ 10% in both groups (8% vs. 9%, p = 1.000). There was no mortality in either group. Conclusions Operative risk was generally similar between omentectomy and omentum-preserving surgery for locally advanced gastric cancer.

Efficacy of Omentum-Preserving Gastrectomy for Patients With Gastric Cancer: A Systematic Review and Meta-Analysis

“…Seven studies (4, 5, 7-10, 12) reported the number of retrieved lymph nodes of both groups, and the difference between the two groups was not statistically significant (MD = 2.16, 95% CI = −0.61 to 4.93, P = 0.13) (Figure 4C). Seven studies (3)(4)(5)(9)(10)(11)(12) reported the postoperative complications of both groups, and no significant difference between the OPG and GCO groups was observed (OR = 0.92, 95% CI = 0.74 to 1.15, p = 0.47) (Figure 4D).…”

“…A total of 920 studies were identified. Nine studies (3)(4)(5)(7)(8)(9)(10)(11)(12), including 8 retrospective studies and 1 randomized controlled trial, were ultimately included in this meta-analysis. Three multicenter studies were obtained.…”

“…In recent years, some retrospective studies reported omentum-preserving gastrectomy (OPG), in which the greater omentum is dissected 3 cm far from the gastroepiploic arcade, whereas the greater omentum on the side of the transverse colon is preserved. These studies pointed out that GCO increases operative time, intraoperative blood loss, or postoperative complications but provides no oncological advantage over OPG for patients with GC (3)(4)(5). Therefore, further research is needed to assess the efficacy of OPG in GC surgery, but no largescale randomized controlled trial is available to date.…”

Efficiency of complete omentectomy in patients with resectable gastric cancer: a meta‑analysis and systematic review

“…Of the nine studies, eight were conducted in East Asia (Korea or Japan), and one was conducted in the US. Of the nine studies, one was an RCT [ 10 ] and the remaining eight were retrospective comparative studies, with four using PSM. The study period of the included studies ranged from 2000 to 2018.…”

“…Four studies reported data on estimated blood loss with high heterogeneity [ 4 , 10 , 11 , 17 ]. The meta-analysis revealed that the CO group was associated with significantly more estimated blood loss than the NCO group (WMD = 250.90, 95% CI 105.90–396.28, P = 0.0007, I 2 = 98%, Fig.…”