Efficacy evaluation and survival analysis of the combination of oxaliplatin plus Teysuno (SOX) with immune checkpoint inhibitors in the conversion therapy of locally advanced gastric cancer

Abstract

Abstract Background The efficacy of combining immune checkpoint inhibitors (ICIs) with chemotherapy in neoadjuvant therapy for locally advanced gastric cancer has been explored. However, limited research exists on its effectiveness in conversion therapy, and its superiority over standalone chemotherapy remains to be elucidated. This study aims to investigate the efficacy and survival outcomes of patients treated with ICIs in combination with conversion therapy for locally advanced gastric cancer. Methods Retrospective data from patients with locally advanced gastric cancer treated with either oxaliplatin + S-1(SOX) alone or in combination with ICIs in conversion therapy were collected. Clinical and pathological characteristics, disease-free survival, and efficacy assessments in nonoperable patients were compared between the 2 treatment groups. Efficacy was further evaluated through dynamic changes in serum markers, and patients’ quality of life was assessed using the QLQ-STO22 (Gastric Cancer–Specific Quality of Life Questionnaire) quality-of-life measurement scale. Results A total of 140 patients underwent conversion therapy: 80 in the SOX alone group and 60 in the SOX combined with the ICIs group. There were no significant differences in baseline characteristics between the 2 groups. Compared with the SOX alone group, the SOX combined with ICIs group exhibited a higher conversion rate (83.3% vs 75%, P = 0.23), R0 resection rate (90.0% vs 83.3%, P = 0.31), pathological complete response (pCR) rate (18% vs 5%, P = 0.02), median disease-free survival (21.4 vs 16.9 months, P = 0.007), the objective response rate in nonoperable patients (60% vs 40%, P = 0.301), and median progression-free survival time (7.9 vs 5.7 months, P = 0.009). The QLQ-STO22 quality-of-life assessment revealed statistically significant improvements in pain, swallowing difficulties, and dietary restrictions in the combination therapy group compared with those in the monotherapy group. The enhanced efficacy of immune combination with SOX is evident, as demonstrated by the significantly prolonged surgical duration in operated patients (206.6 ± 26.6 min vs 197.8 ± 19.8 min, P = 0.35) and intraoperative blood loss (158.9 ± 21.2 mL vs 148.9 ± 25.1 mL, P = 0.59). No significant differences were observed in postoperative complications. Conclusions Compared with the SOX conversion therapy regimen, SOX combined with ICIs demonstrated higher conversion rates, R0 resection rates, pathological response rates, and disease-free survival without increasing surgical difficulty or complications. Nonoperable patients also experienced longer progression-free survival and objective response rates.