Effectiveness of neoadjuvant chemotherapy with a docetaxel, cisplatin, and S-1 (DCS) regimen for T4b gastric cancer.

[BACKGROUND] No studies on neoadjuvant chemotherapy for gastric cancer (GC) with T4b stage were reported. This study aimed to assess the effectiveness of neoadjuvant chemotherapy using DCS regimen (docetaxel, cisplatin, and S-1) for GC with T4b stage.

[METHODS] Forty-three patients diagnosed GC with surgical or clinical T4b stage received three or four preoperative cycles of DCS therapy followed by gastrectomy and lymphadenectomy between Jan-2018 and Dec-2022. Short-tern outcomes including tumor response, completion of neoadjuvant chemotherapy, toxicity and adverse events, rate of treatment-related death, R0 resection, rate of complete adjuvant chemotherapy and short-term surgical results were investigated. The oncologic outcomes comprised 3-year OS and 3-year disease-free survival (DFS).

[RESULTS] A total of 43 patients with T4b gastric cancer were included in the analysis. Among them, twenty-five patients underwent gastrectomy and lymphadenectomy. The completion rate of neoadjuvant chemotherapy was 88.4%, including 4 cycles of 51.2% and 3 cycles of 37.2%. The disease-control and clinical response rate were 88.4% and 58.1%, respectively. During preoperative chemotherapy, grade 3/4 neutropenia occurred in 20.9%, anemia in 13.9%, hyponatremia in 4.8%, and vomiting in 2.3%. Pathologic complete response was achieved in 8.0%. After surgery, no patient experienced severe complications (Clavien Dindo > = 3). The R0 resection rate was 72.0% and the rate of complete adjuvant chemotherapy was 83.3%. The 3-year OS and DFS rates were 49% and 38%, respectively.

[CONCLUSIONS] Neoadjuvant chemotherapy with DCS regimen demonstrated a high tolerance, high tumor response rate, high complete adjuvant chemotherapy rate and satisfactory 3-year survival outcomes. Three- or four-course of preoperative DCS regimen is a promising approach for GC with T4b stage.