A phase II study of neoadjuvant chemotherapy with docetaxel, cisplatin, and S-1, followed by gastrectomy with D2 lymph node dissection for high-risk advanced gastric cancer: results of the KDOG1001 trial.

Background: The prognosis of patients with gastric cancer with bulky node metastasis, linitis plastica (type 4), or large ulcero-invasive-type tumors (type 3) remains poor. We conducted a phase II study to evaluate the safety and efficacy of neoadjuvant chemotherapy with docetaxel, cisplatin, and S-1 (DCS) for establishing a new treatment modality that improves prognosis.

Methods: Patients received up to four 28-day cycles of DCS therapy (docetaxel at 40 mg/m, cisplatin at 60 mg/m on day 1, and S-1 at 40 mg/m twice daily for 2 weeks) followed by gastrectomy with D2 nodal dissection. S-1 chemotherapy was administered for 1 year after surgical resection. The primary endpoint was the percentage of complete resections of the primary tumor with clear margins (R0 resection). The planned sample size was 40; this was calculated based on an expected R0 rate of 85% and a threshold R0 rate of 65%, with a one-sided alpha of 5% and a power of 90%.

Results: Between 2010 and 2017, 40 patients were enrolled. The R0 resection rate was 90%. The most common grade 3 or 4 adverse events during DCS therapy were leukocytopenia (27.5%), neutropenia (55.0%), and hyponatremia (22.5%). The most common grade 3 or 4 surgical morbidity was pancreatic fistula (12.5%); mortality was 0%. The pathological response rate was 57.5% with a grade 3 histological response rate of 8%.

Conclusions: Neoadjuvant chemotherapy with DCS was feasible and showed a sufficient R0 resection rate. A future study with a sufficient follow-up period should confirm survival outcomes.