Neoadjuvant chemotherapy plus surgery for high-risk advanced gastric cancer: Long-term results of KDOG1001 trial.

Abstract

4521 Background: In the phase 2, open-label, KDOG1001 (UMIN000003642) study, neoadjuvant chemotherapy (NAC) with docetaxel, cisplatin, and S-1 (DCS), followed by gastrectomy with D2 lymph node dissection for high-risk advanced gastric cancer showed feasibility of DCS therapy with an enough R0 resection rate of 90%. Here we present long-term results after a minimum follow-up of 3 years. Methods: Patients with bulky node metastasis (bulky N), linitis plastica (type 4), or large ulcero-invasive-type tumors (type 3) received up to four 28-day cycles of DCS neoadjuvant chemotherapy (docetaxel at 40 mg/m2, cisplatin at 60 mg/m2 on day 1, and S-1 at 40 mg/m2 twice daily for 2 weeks) followed by gastrectomy with D2 lymphadenectomy. This analysis presents the final preplanned assessment of outcomes after 3 years. Primary endpoint was R0 resection rate. Secondary endpoints included overall survival (OS), progression free survival (PFS), completion rate of the protocol treatment, and pathological response rate (pRR) of DCS NAC. Results: Of 40 patients enrolled from May 2010 through January 2017, 7 (17.5%) had bulky N, 18 (45.0%) had type 4, and 16 (40%) had large type 3 with 1 (2.5%) having both large type 3 and bulky N2. All included patients underwent preoperative DCS chemotherapy followed by surgery with D2 lymphadenectomy with 32 (80%) completed postoperative S-1 therapy for 1 year. After a median follow-up for surviving patients of 67 mo (range, 36 mo to 110 mo) at the last follow-up in January 2020, 3-year OS was 78% [95% confidence interval (CI) 62–88%], while 3-year PFS was 63% (95% CI 47–76%). Completion rate of the protocol treatment was 62.5% (25/40) with pRR of 57.5% (23/40). In bulky N2, 3-y OS was 86% and 3-y PFS was 71% with pRR of 100%. In type 4, 3-y OS was 67% and 3-y PFS was 50% with pRR of 44%. In large type 3, 3-y OS was 88% and 3-y PFS was 75% with pRR of 56%. Patients with type 4 had significantly worse OS and PFS than those with the other types [HR 7.20 (95% CI 2.23–32.21) and HR 3.00 (95% CI 1.21–8.19)]. Conclusions: Preoperative chemotherapy with up to four cycles of DCS followed by gastrectomy plus adjuvant S-1 therapy is a promising treatment strategy for patients with bulky node metastasis, type 4 and large type 3 gastric cancers. For type 4 cancer, further improvement of treatment strategy is needed. Clinical trial information: 000003642 .