Long-term complete response to nivolumab after recurrent Stage IV gastric cancer

What happened, in summary

A 70-year-old woman sought care for epigastric pain and was diagnosed with well-differentiated gastric adenocarcinoma. Preoperative imaging suggested Stage III disease with possible pancreatic invasion. During total gastrectomy with splenectomy and removal of the pancreatic tail, small disseminated nodules were found in the specimen, changing the final diagnosis to Stage IV gastric cancer. The tumor was HER2-negative.

She began S-1 plus cisplatin chemotherapy. Cisplatin was stopped after 7 courses because of severe appetite loss and weight loss, while S-1 continued. Three years after surgery, a nodule appeared near the pancreatic stump. Radiation and docetaxel were used, and the nodule initially shrank. About a year later, new peritoneal disease and enlarged distant lymph nodes showed further progression.

Nivolumab was then started. Serial CT scans gradually stopped showing the recurrent nodules or lymph-node swelling, and she achieved a complete clinical response. About 3.5 years after starting nivolumab, tumor markers had normalized, her weight had improved from 37 kg to 49 kg, and she had returned to work. At the latest follow-up, around 7 years after surgery, she was still receiving nivolumab with no evidence of recurrence.