Abstract
AIMS: Second-line chemotherapy (SLC) improves survival in advanced gastric cancer (AGC). Although many patients receiving SLC have undergone gastrectomy, the impact of gastrectomy on SLC remains unclear. PATIENTS AND METHODS: The objective was to evaluate the impact of gastrectomy on SLC for AGC. A total of 290 eligible patients registered in two randomized phase III trials evaluating SLC for patients with AGC was classified into the prior gastrectomy group (PGG; n = 187) or the no gastrectomy group (NGG; n = 103). We compared overall survival (OS), progression-free survival (PFS), overall response rate (ORR), disease control rate (DCR), and safety between these two groups. Adjusted OS and adjusted PFS were estimated using inverse probability of treatment weighting (IPTW). RESULTS: The PGG had better performance status (p = 0.001), more prior platinum agent (p < 0.001), and more frequent peritoneal metastasis (p = 0.006) than the NGG. The PGG had significantly better OS (13.8 vs. 9.3 mo; hazard ratio [HR]: 0.59; p < 0.001) and PFS (4.7 vs. 2.8 mo; HR: 0.58; p < 0.001) than the NGG. The PGG had significantly better adjusted OS (13.8 vs. 10.0 mo; IPTW HR: 0.66; p = 0.01) and adjusted PFS (4.3 vs. 3.2 mo; IPTW HR: 0.71; p = 0.027) than the NGG. No significant differences were observed in ORR and DCR. The incidence of Grade 3 or worse adverse events did not differ between the two groups except for a high incidence of anemia and diarrhea in the NGG. CONCLUSION: Patients with previous gastrectomy are expected to have better survival outcomes when receiving second-line irinotecan (IRI)-based chemotherapy for AGC.