A patient with stage IV type 4 advanced gastric cancer who had a complete pathological response to short-term treatment with S-1 alone

An 81-year-old woman presented with dysphagia. Stage IV (cT3, cN3, cH0, cM1) type 4 advanced gastric cancer was diagnosed. The left adrenal gland and the paragastric, mediastinal, and abdominal para-aortic lymph nodes were enlarged. Ascites was present The patient started to receive S-1 (100 mg/day), given orally for 4 weeks followed by 2 weeks of rest. During the first course of treatment, grade 2 anorexia, grade 2 vomiting, and grade 2 diarrhea developed. Treatment with S-1 was therefore discontinued on day 27 The tumor had shrunk and was severely deformed. There was marked narrowing of the pyloric antrum. Abdominal computed tomography revealed that ascites and enlargement of the left adrenal gland and paragastric lymph nodes had resolved. To ensure adequate oral intake and improve the patient's quality of life, a total gastrectomy with a limited (D1) lymph node dissection was performed. The primary gastric tumor, resected lymph nodes, and a peritoneal-lavage specimen were all negative for tumor. Histologically, the tumor had a complete pathological response to S-1. Two years after surgery, the patient is alive, with no evidence of metastasis or recurrence.