A phase II study of preoperative chemotherapy with S-1 (S) and cisplatin (P) followed by D3 gastrectomy for gastric cancer (GC) with extensive lymph node metastasis (ELM): Survival results of JCOG0405.

Abstract

70 Background: GC with ELM, especially in case of M1(LYM), is regarded unresectable in many countries, while challenge is ongoing in Japan to treat them by intensive chemotherapy followed by super extended surgery. In our previous phase II study (JCOG0001) for the same population, iritotecan plus P (IP) chemotherapy followed by surgery showed remarkable survival of 27.0% at 3 years but its toxicity led to rather high treatment related death (TRD). Development of safer and more effective treatment is urged. Methods: Eligibility criteria included histologically proven gastric adenocarcinoma; bulky nodal involvement around major branched arteries to the stomach and/or para-aortic nodal metastases; cM0 (except para-aortic nodes); negative lavage cytology; not linitis plastica type; PS of 0 or 1. Patients (pts) received two or three 28- day cycles of induction chemotherapy of S (80 mg/m2 from day 1 to 21) and P (60 mg/m2 on day 8), and then underwent D3 gastrectomy. Primary endpoint was R0 resection and key secondary endpoint was 3-year survival. Other secondary endpoints included response rate and adverse events. Results: Between 02/2005 and 06/2007, 53 pts were enrolled and 2 pts were ineligible. Only surrogate endpoints of efficacy and feasibility were reported in ASCO-GI 2008, which included clinical response of 64.7%, R0 of 82.4%, pathological response of 51.0%, and no TRD with low toxicities. The 3-year overall survival, which we first clarified in this report, was 58.8% (95% CI, 44.1-70.9%). Conclusions: Preoperative SP followed by D3 gastrectomy demonstrated excellent 3-year survival with low mortality compared with preoperative IP, which was far better result than expected against this unresectable population. This multimodal treatment is highly promising for GC with ELM. [Table: see text]