[A case of advanced gastric cancer attaining histological CR of paraaortic lymph node after TS-1/CDDP neoadjuvant chemotherapy].

A 60-year-old male complaining of anemic symptoms went through examinations and was diagnosed with gastric cancer (cardia, type 3', cT2, cN3, cH0, cP0, cM0, cStage IV). Further inspection showed multiple lymph node metastases, including, No. 1, 3, 7, 11, and 16 (paraaortic LNs). Poor prognosis was predicted, yet we tried neoadjuvant chemotherapy (NAC) expecting down staging of the tumor. With the efficacy and safety previously proven, we chose TS-1 + CDDP as NAC regimen. TS-1 (tegafur gimestat otastat potassium, = 80 mg/m2) was administered orally for 21 days, followed by CDDP (cisplatin, = 60 mg/m2) i.v. on day 9. One course was completed without any significant adverse effects. The tumor itself showed PR-MR to the chemotherapy, but all the lymph nodes were expected to attain PR from CT findings. Total gastrectomy, lymph node dissection (D3) with Roux-en-Y reconstruction was performed, and histological re-evaluation was made. Macroscopically, the stomach seemed to be penetrated into serosa by the tumor, i.e., se invasion was suggested, yet histologically no cancerous cells were detected within mp and ss layer. Many of the lymph nodes were replaced with fibrosis, some with normal lymph node structure remained. Definitely no malignant cells were detected throughout all the lymph node specimens (Grade 3). Because pathological CR of paraaortic lymph nodes has never been reported previously, this case shows TS-1 + CDDP as a promising NAC regimen for advanced gastric cancer, in a sense that tumors once diagnosed as inoperable would still have the possibility of CR.