A phase II study of systemic chemotherapy with docetaxel, cisplatin, and S-1 (DCS) followed by gastrectomy with D2 plus para-aortic lymph node (PAN) dissection for gastric cancer with extensive lymph node metastasis (ELM): Japan Clinical Oncology Group Study JCOG1002.
116 Background: Gastric cancer with ELM is commonly regarded as unresectable with poor prognosis. We previously reported the safety and efficacy of cisplatin and S-1 (CS) followed by D2 gastrectomy with PAN dissection for this target (JCOG0405, Br J Surg 2014). Methods: Eligibility criteria included histologically proven gastric adenocarcinoma; bulky nodal involvement around major branched arteries to the stomach (Bulky N) and/or PAN metastases; cM0 (except PANs); negative lavage cytology; neither Borrmann type 4 nor large (8cm or more) type 3; PS 0 or 1. Patients received two or three cycles of induction chemotherapy of docetaxel (40mg/m2 day1), cisplatin (60mg/m2 day1), and S-1 (80mg/m2from day 1 to 14) every 4 weeks, and then underwent D2 gastrectomy with PAN dissection. After R0 resection, postoperative chemotherapy with S-1 was given for one year. The primary endpoint is response rate (RR) of NAC by central peer review. The planned sample size was 50 patients, provided 80% power under the hypothesis of primary endpoint as the expected RR of 80% and threshold RR of 65% with a one-sided alpha of 10%. Results: Between 07/2011 and 05/2013, 53 patients were enrolled and 1 patient was ineligible: 30 had Bulky N, 14 had PAN metastases, and 9 had both. 51of 52 patients (98.1%) completed a planned NAC. The clinical RR was 57.7% (30/52) (80%CI [47.9%-67.1%], one-sided p=0.89). The R0 resection rate was 84.6% (45/52). During DCS chemotherapy, grade 3/4 neutropenia occurred in 39.6% and grade 3/4 non-haematological adverse events in 20.8%. The incidence of grade 3/4 adverse events related to surgery was 30.6%. There was no treatment-related death. The pathological finding revealed minor response (residual tumor <1/3) was achieved in 50.0% (26/52) and major response (residual tumor <2/3) in 34.6% (18/52). The long-term survival is still under follow-up. Conclusions: Preoperative DCS revealed feasible but could not show sufficient efficacy. Preoperative CS is still being considered a standard treatment for this population. Clinical trial information: UMIN000006069.