The impact of combination chemotherapy administration on prognostic outcomes in stage II and III gastric cancer: a comprehensive analysis utilizing propensity score matching.

[OBJECTIVE] Limited data are available on the effects of combined and intravenous or oral chemotherapy on the survival of patients who have undergone D2 gastrectomy for cancer.

[METHODS] This study involved 1314 patients who participated in a trial that followed D2 gastrectomy with adjuvant or neoadjuvant chemotherapy.

[RESULTS] Following propensity score matching (PSM), the results indicated that contrary to expectations, combined chemotherapy administration was associated with poorer overall survival (OS) and progression-free survival (PFS) at the 5-year mark for stage II gastric cancer, with log-rank values of 0.005 for OS (83.6% vs. 68.8%) and 0.005 for PFS (71.6% vs. 61.5%). Significant differences were observed in the recurrence rate (P < 0.001) and local-regional recurrence (P = 0.009), although no significant difference was found for distant metastasis (P = 0.146). For stage III gastric cancer, the Kaplan-Meier survival curves showed that the combination of oral and intravenous chemotherapy was inferior to single-modality chemotherapy for PFS (P = 0.006). However, it did not differ significantly from single therapy in OS (P = 0.257). Notable discrepancies were evident in the recurrence rate (P < 0.001), distant metastasis (P < 0.001), and local-regional recurrence (P = 0.003).

[CONCLUSIONS] The findings suggest that the concurrent use of oral and intravenous chemotherapy after D2 gastrectomy does not enhance the prognosis for gastric cancer patients compared to using either modality alone. Instead, it appears to increase the risk of disease progression for stage III patients and the likelihood of recurrence for both stages II and III of gastric cancer.