Bursectomy, the total resection of the bursa omentalis, is a standard procedure in gastrectomy for resectable gastric cancer. A phase III trial (JCOG1001) comparing bursectomy and omentectomy alone was terminated early at the interim analysis. The final results of the updated analysis after a minimum follow-up of 5 years are reported here.

Patients with histologically proven adenocarcinoma of the stomach (cT3-T4a) were randomized (1 : 1) during surgery to bursectomy or omentectomy-alone groups and then underwent D2 gastrectomy. The primary endpoint was overall survival, analysed on an intention-to-treat basis.

A total of 1204 patients (602 bursectomy and 602 omentectomy alone) were enrolled between June 2010 and March 2015. The bursectomy group had a significantly higher incidence of Clavien-Dindo grade III-IV intra-abdominal abscess than the omentectomy-alone group (5.5 versus 2.5 per cent respectively; P = 0.008). The updated 5-year overall survival rates were 74.9 (95 per cent c.i. 71.2 to 78.2) per cent in the bursectomy group and 76.5 (72.8 to 79.7) per cent in the omentectomy-alone group; the adjusted HR for death in the bursectomy group was 1.03 (95 per cent c.i. 0.83 to 1.27) (1-sided P = 0.598). Bursectomy did not decrease peritoneal recurrence (12.1 versus 12.3 per cent respectively; P = 1.000). In a multivariable analysis, old age (above 65 years), tumour located in the lower third or posterior wall of the stomach, macroscopic type 3/5, total gastrectomy, and cT4a were independent predictors of poor overall survival, but omentectomy alone was not.

In D2 gastrectomy, bursectomy is not recommended as a standard procedure for cT3-T4a gastric cancer. Registration number: UMIN000003688 (https://www.umin.ac.jp/ctr/).