An integrated analysis of two phase II trials (JCOG0001 and JCOG0405) of preoperative chemotherapy followed by D3 gastrectomy for gastric cancer with extensive lymph node metastasis

Background Gastric cancer with extensive lymph node metastasis is commonly regarded as unresectable, while preoperative chemotherapy followed by gastrectomy has been tested since 2000 in JCOG (JCOG0001 and JCOG0405). The survivals were quite different between the trials despite the similar eligibility criteria. The aim of this study was to investigate if survival is still better in JCOG0405 after adjusting baseline factors and if there is any subset of patients who benefit more from either treatment. Methods Eligibility criteria for both trials included histologically proven gastric adenocarcinoma; bulky nodal involvement around the celiac artery and its major branches (bulky N) and/or para-aortic lymph node (PAN); cM0 (except PAN); negative lavage cytology; not linitis plastica type; PS of 0 or 1. Patients received two or three cycles of preoperative chemotherapy of irinotecan plus cisplatin in JCOG0001, or S-1 plus cisplatin in JCOG0405, followed by D3 gastrectomy. Multivariable analysis for overall survival adjusting baseline and treatment factors was performed with the Cox regression model. Results After adjusting baseline factors, S-1 plus cisplatin was superior to irinotecan plus cisplatin for overall survival (HR = 0.39: 95% CI 0.22-0.67). The 5-year overall survival was poor for patients with bulky N+/PAN+ (19.2%) compared with bulky N+/PAN- (50.7%) or bulky N-/PAN+ (43.5%). Conclusions S-1 plus cisplatin was shown to be a favorable preoperative treatment for gastric cancer with extensive lymph node metastasis by multivariable analysis, while poor prognosis in patients having both bulky N+ and PAN+ may necessitate further treatment improvement.