Changes in and Prognostic Impact of Chemotherapeutic Strategy in Patients With Advanced Gastric Cancer: A Retrospective Study

Background: The Japanese Gastric Cancer Treatment Guidelines 2018 have recommended first- to third-line treatment regimens after nivolumab approval for unresectable advanced gastric cancer. However, the clinical impact of chemotherapeutic changes, including post-progression chemotherapy (PPC), remains unclear. Therefore, the current study aimed to investigate changes in PPC before and after nivolumab approval and determine their prognostic impact. Methods: : A total of 146 patients with unresectable gastric cancer who had at least progressive disease after first- and/or second-line chemotherapy were retrospectively enrolled. All patients were divided into two groups based on the nivolumab approval period. Results: : Among the 146 patients, 46 and 23 received ramucirumab and nivolumab, respectively. Moreover, 95 and 62 patients received PPC after first- and second-line chemotherapy, respectively. Group B (i.e., at least chemotherapy after nivolumab approval) had significantly higher proportions of patients receiving ramucirumab therapy, nivolumab therapy, and PPC after first- or second-line chemotherapy compared to group A (i.e., termination of chemotherapy before nivolumab approval) (all p < 0.0001). Group A had significantly poorer prognosis than group B ( p = 0.0002). Multivariate analysis showed that age (< 70 vs. ³ 70), number of distant metastatic sites (1 vs. ³ 2), and ramucirumab therapy were independent prognostic factors ( p = 0.0252, p = 0.0036, and p = 0.0076, respectively). Conclusion: Our retrospective study demonstrated that changes in chemotherapeutic strategy might contribute to improved prognosis in patients with advanced gastric cancer.