Conversion hepatectomy after chemotherapy including nivolumab for multiple liver metastases of hepatoid adenocarcinoma of the stomach: A case report and literature review.

Introduction: Currently, there is no evidence of the effectiveness of surgical intervention for Stage IV gastric cancer (GC); however, there are scattered reports of hepatectomy for liver metastasis of GC after chemotherapy including nivolumab.

Presentation of case: We report a case of a 79-year-old man with a history of laparoscopic distal gastrectomy with D2 lymph node dissection for GC, pathologically diagnosed as hepatoid adenocarcinoma of the stomach (HAS), with a combined positive score (CPS) for programmed death (PD)-ligand 1 was >5. Six months after gastrectomy, magnetic resonance imaging (MRI) showed multiple masses in both lobes of the liver, and the patient was treated with a regimen consisting of nivolumab and capecitabine with oxaliplatin (CapeOX). After 11 courses of nivolumab and CapeOX therapy, MRI revealed reduced tumor sizes in both lobes of the liver. The patient underwent left lateral sectionectomy and partial resection of the liver. No new recurrences were observed, and the patient has survived for 15 months after hepatectomy.

Discussion: The recent emergence of PD-1 inhibitors has improved the prognosis of unresectable advanced or recurrent GC. Hepatectomy for liver metastasis of GC can be effective if the conditions are met. In this case, both the resected gastric tumor and metastasis in the left lateral hepatic segment had a CPS > 5, suggesting that nivolumab with CapeOX therapy could control the disease status from unresectable to resectable liver metastasis.

Conclusion: Using multidisciplinary treatment, R0 surgery was successfully performed in a patient with multiple unresectable liver metastases of HAS.