A Case of Long-Term Progress Control of Unresectable Progressive Gastric Cancer with Nivolumab Introduced during Effective Duration of Secondary Treatment

A 65-year-old man with 1 month of general malaise was admitted to our hospital. Thoracoabdominal CT showed that the supra-clavicular, sub-carina, and para-aortic lymph nodes were swelling. Upper gastrointestinal endoscopy revealed 2 type 1 tumors at the esophagogastric junction, and the biopsy showed Group 5, well to moderately differentiated adenocarcinoma. The clinical diagnosis was cardiac gastric cancer and cStage Ⅳ(cT3N3M1[LYM]). We started capecitabine plus oxaliplatin as the first-line chemotherapy, and weekly paclitaxel plus ramucirumab was administered as the second-line treatment. The second-line treatment was successful, and the effect of PR was obtained. However, considering the period of TTF, while the therapeutic effect continued, we switched to third-line treatment with nivolumab after 7 courses of the second treatment. With the third-line treatment, PR was maintained for 1 year and 3 months, and good quality of life and performance status were obtained for a long period without irAE. However, after 32 courses, because the tumor marker was elevated and lymph nodes were enlarged, we judged PD and switched to the fourth-line treatment with nab-paclitaxel plus ramucirumab. The tumor marker levels decreased, the lymph nodes shrank, and PR was achieved again with the fourth-line treatment. The treatment is still ongoing 2 year and 8 months after the diagnosis.