Marked response to S-1 chemotherapy for para-aortic lymph node metastasis arising from gastric cancer

We report a recurrent case of gastric cancer with para-aortic lymph node metastasis that showed a marked response to systemic chemotherapy consisting of S-1 alone. A 70-year-old male was admitted to our hospital with appetite loss and left abdominal pain. He had a history of distal gastrectomy due to the advanced gastric cancer. Endoscopy revealed a submucosal tumor-like elevation with central ulcer, and the biopsy specimen was poorly-differentiated adenocarcinoma histologically. CT of the abdomen demonstrated a para-aortic lymph node swelling behind the remnant stomach, indicating an unresectable recurrent gastric cancer. We initially treated the patient with S-1 chemotherapy (60 mgx2/day) by oral administration. His tumor immediately responded to the chemotherapy, and restaging abdominal CT after 2 cycles of chemotherapy showed almost complete regression of lymph node metastasis. The patient has undergone S-1 chemotherapy and currently has remained in remission for more than 21 months with no severe adverse events. The S-1 regime was effective and safe, suggesting that S-1 could be the first-line chemotherapy for recurrent gastric cancer.