Nivolumab is one of the
immune checkpoint inhibitors available for
chemotherapy-resistant
gastric cancer. There have been few reports of confirmed prominent shrinkage of the primary
tumor and some reports of prolonged antitumor effect after discontinuance of the drug, but it is not universal. A 67-year-old male was admitted to our hospital and diagnosed with metastatic
gastric cancer that had spread to the bilateral lobe of the liver, distant lymph nodes, and peritoneum. He received five courses of S-1 plus
oxaliplatin, followed by three courses of
ramucirumab plus
paclitaxel leading to
disease progression. Then, the patient was administered
nivolumab as third-line
therapy.
Tumor size was markedly reduced after three courses, esophagogastroduodenoscopy (EGD) revealed
scar formation on the lower gastric corpus after seven courses, and biopsy specimen showed no
malignancy. When a slight lower limb
muscle weakness manifested, possibly an immune-related adverse event (irAE) after 15 courses, we stopped administration of
nivolumab. The patient has survived for 26 months since his first visit, and elimination of the primary
tumor and
ascites with noted shrinkage of liver and
lymph node metastases have followed for more than 10 months since discontinuance of
nivolumab.