Prospective single-arm multicenter interventional study of surgical resection for liver metastasis from gastric cancer; 3-year overall and recurrence-free survival.

Objective: Potential benefit of surgical resection for liver metastasis from gastric cancer (LMGC) remains controversial because most previous studies were retrospective. We evaluated the outcomes of surgical resection following chemotherapy for LMGC in a prospective single-arm multicenter interventional study.

Methods: Patients with synchronous or metachronous LMGC received 2-4 cycles of standard chemotherapy and proceeded to surgical resection if restaging showed a non-progressive disease with a chance of R0 resection. The primary endpoint was 3-year OS of R0 patients, with RFS as secondary. Prognostic factors for R0 patients were evaluated by multivariable Cox regression analysis.

Results: Seventy patients were enrolled between 2011 and 2019. Two patients were ineligible, and 20 discontinued treatment before surgery. Of the 48 patients eventually undergoing surgery, 43 accomplished R0 resection of the primary and/or metastatic GC, while 1 ended in R2 resection and 4 were considered ineligible. Median and 3-year OS for R0 patients were 39.8 months (95 % confidence interval [CI], 26.9 to not reached) and 58.1 % (95 % CI, 43.1-71.8), respectively, while median and 3-year RFS were 14.9 months (95 % CI 7.9-34.0) and 34.9 % (95 % CI 22.2-50.1), respectively. On multivariable analysis, both multiple liver metastases and positive nodal status (pN1-3) were negatively associated with OS (multiple liver metastases: hazard ratio [HR] 2.71 (95 % CI, 1.16-6.35), P = 0.022; pN1-3: HR 9.11 (95 % CI, 1.22-68.2), P = 0.031).

Conclusion: R0 resection following chemotherapy for LMGC yielded promising survival, with multiple liver metastases and positive nodal status being significant indicators of poor prognosis.

Clinical Trial Registration Number: UMIN 000011445 (https://www.umin.ac.jp/ctr/).