# Conversion Surgery via Laparoscopic Gastrectomy and Hepatectomy for Advanced Gastric Neuroendocrine Carcinoma with Extensive Liver Metastases: A Case Report

## TL;DR

A rare case of advanced stomach neuroendocrine cancer with liver spread was successfully treated with surgery after chemotherapy, showing potential for improved outcomes.

## Contribution

This case report demonstrates the successful use of conversion surgery after chemotherapy for advanced gastric neuroendocrine carcinoma with liver metastases.

## Key findings

- Chemotherapy reduced tumor size and made previously unresectable G-NEC amenable to curative surgery.
- R0 resection was achieved with no viable tumor cells in lymph nodes or liver specimens post-surgery.

## Abstract

Gastric neuroendocrine carcinoma (G-NEC) is a rare but highly aggressive malignancy that often presents with distant metastases and significantly worsens prognosis. Recent studies have suggested that conversion surgery after chemotherapy may improve outcomes in initially unresectable gastric cancers; however, evidence regarding its application in G-NEC remains limited. We report a rare case of advanced G-NEC with multiple liver metastases that was treated with R0 resection through conversion surgery after chemotherapy.

A 73-year-old man presented with postprandial heartburn and abdominal pain. Upper gastrointestinal endoscopy revealed a type 3 tumor with submucosal tumor-like elevation. Endoscopic biopsy confirmed G-NEC, and computed tomography revealed lymph node enlargement and seven liver lesions, leading to a diagnosis of T2N1M1 (Stage IVB). The patient was initially treated with etoposide and cisplatin (EP) for unresectable G-NECs. Following 13 courses of chemotherapy, significant tumor reduction was observed, with the disappearance of lymph node metastasis and marked shrinkage of liver metastases. Because all lesions, including liver metastases, were deemed resectable, conversion surgery was performed. The surgical approach consisted of laparoscopic distal gastrectomy with D2 lymph node dissection, laparoscopic left medial hepatic segmentectomy, partial hepatectomy, and cholecystectomy. Pathological examination revealed residual tumor cells at the primary site; however, no viable tumor cells were detected in the lymph nodes or liver resection specimens, indicating a marked response to chemotherapy. R0 resection was confirmed at the final staging of T2N0M0 (Stage IB).

This case highlights the fact that effective chemotherapy may render initially unresectable G-NECs amenable to curative conversion. Successful R0 resection and a substantial response of liver metastases to EP chemotherapy demonstrated the potential viability of this approach in achieving improved patient outcomes.