Stage IV gastric cancer with liver metastases cleared after chemotherapy, nivolumab and surgery

What happened, in summary

A 66-year-old man was hospitalized in July 2019 after 3 months of upper-abdominal fullness, swallowing difficulty and major weight loss. Endoscopy found a mass in the gastric fundus extending to the cardia, and biopsy showed poorly differentiated adenocarcinoma. CT revealed seven liver metastases. Testing showed PD-L1-positive, HER2-negative, microsatellite-stable disease.

An acute gastric hemorrhage led to laparoscopic total gastrectomy with lymph-node dissection. The liver metastases could not be removed at that time, confirming Stage IV disease. He then received S-1 plus oxaliplatin chemotherapy. The liver lesions remained largely unchanged, so nivolumab was added. After four cycles of nivolumab, imaging showed marked shrinkage of the liver disease.

Nivolumab was later stopped when he developed severe immune-related pneumonitis, and his longstanding psoriasis also worsened during treatment. Chemotherapy continued, reaching 16 cycles in total. After his lung inflammation improved, surgeons removed the remaining liver lesion; pathology found inflammatory cells but no viable tumor. Follow-up PET and CT showed disappearance of the liver metastases and no recurrence in the stomach. Anticancer treatment was stopped, and he remained relapse-free with no evidence of disease for 32 months.