Clinical Impact of Low-Dose Neoadjuvant Chemotherapy in Advanced Gastric Cancer or Esophagogastric Junction Cancer: A Retrospective Analysis

Background. This study aimed to evaluate the efficacy and safety of low-dose neoadjuvant chemotherapy with an oral fluoropyrimidine containing tegafur, gimeracil, and oteracil (S-1) and oxaliplatin (NAC-SOX) in improving resectability and long-term outcomes in patients with advanced gastric cancer. Methods. This was a single-center, retrospective study analyzing patients with advanced gastric cancer or esophagogastric junction cancer who received NAC-SOX. (S-1: 80–120 mg/m2, oxaliplatin: 100 mg/m2) followed by gastrectomy with D2 lymphadenectomy. Clinical background, chemotherapy-related adverse effects, surgical outcomes, pathological response, and survival were assessed. Results. A total of 34 patients underwent NAC-SOX, with a median age of 74 years. The most common surgical procedure was total gastrectomy (n = 16). Peripheral neuropathy was the most frequent adverse effect, but no grade 4 toxicities were observed. Postoperative complications (≥CD grade 3a) occurred in 8.8% of cases, with no treatment-related deaths. R0 resection was achieved in 85.3% of cases, and the pathological complete response rate was 20.6%. The 3-year recurrence-free and overall survival rates were 71.3% and 83.2%, respectively. Conclusions. Low-dose NAC-SOX demonstrated favorable efficacy and safety, achieving high R0 resection and pathological response rates. Further prospective studies are needed to optimize treatment strategies.