3744 - Primary results of multicenter phase II study of neoadjuvant chemotherapy with S-1 and oxaliplatin for locally advanced gastric cancer (Neo G-SOX PII)

Background

Prognosis for locally advanced gastric cancer (LAGC), such as clinical T4 disease, bulky nodal metastases, type 4 and large type 3 gastric cancer, was not satisfactory even by D2 gastrectomy followed by adjuvant chemotherapy. Neoadjuvant chemotherapy is another promising approach. We conducted a multi-institutional, single-arm, open label, phase II study (Clinical trial information: UMIN000018661). The aim of this study was to evaluate the efficacy and safety of the neoadjuvant chemotherapy of G-SOX followed by gastrectomy with D2/3 lymph node dissection for LAGC.

Methods

Eligibility criteria included histologically proven adenocarcinoma of the stomach; clinical T4; clinically resectable gastric cancer of type 4 or large type 3 (over 8 cm); bulky nodal metastases around major branched arteries to the stomach; resectable peritoneal dissemination (pathological CY1 or P1, except for clinical CY1 or P1). Patients received two cycles of neoadjuvant chemotherapy with S-1 (80 mg/m2, p.o., days 1-14 followed by 1 week rest) and oxaliplatin (130 mg/m2 at day 1), followed by D2 or higher surgery with no residual disease. Patients with pathological R0/1 resection received S-1 (80 mg/m2, p.o., days 1-28 followed by 2 week rest) for 1 year as adjuvant chemotherapy. Primary endpoint was curative resection rate.

Results

Forty-one patients were enrolled from 11 institutions. Of the patients, 39 patients (95%) completed the two courses of neoadjuvant chemotherapy of G-SOX, 37 (90%) received gastrectomy, and 36 (87.8%) received curative resection (R0/1). Pathological response rate after neoadjuvant chemotherapy of G-SOX was 40.5%. Most frequent drug-related adverse events during neoadjuvant chemotherapy of G-SOX were anemia (76%), neutropenia (66%), anorexia (63%) and peripheral sensory neuropathy (63%). No treatment related deaths were observed.

Conclusions

Neoadjuvant chemotherapy of G-SOX is a feasible and one of the promising strategies for patients with LAGC.

Clinical trial identification

UMIN000018661.

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

H. Satake: Honoraria (self): Taiho; Honoraria (self): Yakult. M. Kotaka: Honoraria (self): Taiho; Honoraria (self): Yakult. T. Kato: Honoraria (self): Taiho; Honoraria (self): Yakult. A. Tsuji: Honoraria (self): Taiho; Honoraria (self): Yakult. All other authors have declared no conflicts of interest.