Early-onset chemotherapy-induced neutropenia and ascites control in patients with severe peritoneal metastasis of gastric cancer: a post hoc analysis of the JCOG1108/WJOG7312G trial.

OBJECTIVE: Early-onset chemotherapy-induced neutropenia (EON) is reportedly associated with favorable patient outcomes in various cancers. However, the clinical significance of EON in patients with severe peritoneal metastasis remains unclear. We investigated the associations between EON and clinical outcomes in gastric cancer patients with severe peritoneal metastasis enrolled in the JCOG1108/WJOG7312G trial. METHODS: Among 101 enrolled patients, 95 who survived ≥4 weeks were analyzed using a 4-week landmark approach. EON was defined as the lowest neutrophil count <2000/mm3 within 4 weeks after treatment initiation. We compared overall survival (OS), progression-free survival (PFS), ascites control, oral intake, and safety between the patients with and without EON. RESULTS: Thirty-five patients developed EON and 60 did not. Median OS was 9.8 and 5.8 months in the EON and non-EON groups, respectively [hazard ratio (HR), 0.73; 95% confidence interval (CI), 0.47-1.13; P = .15], while the median PFS was 5.8 and 3.3 months (HR, 0.91; 95% CI, 0.58-1.42; P = .67), respectively. The ascites control rate was significantly higher in the EON group compared with the non-EON group [48.5% (16/33) vs. 25.4% (15/59), P = .04]. Grade ≥ 3 neutropenia though the treatment course was significantly higher in the EON group than in the non-EON group [31.4% (11/35) vs. 11.7% (7/60), P = .03]. CONCLUSIONS: EON was associated with improved ascites control but not with statistically significant differences in OS or PFS. EON may represent an early clinical marker associated with ascites control in gastric cancer patients with severe peritoneal metastasis.