LAUSR

Micro‐Abstract The aim of the study was to retrospectively investigate the association between chemotherapy‐induced neutropenia and survival in metastatic castration‐resistant prostate cancer (mCRPC) patients receiving first‐line docetaxel treatment. Docetaxel‐induced neutropenia is associated with better overall and progression‐free survival in mCRPC. These findings support the hypothesis that chemotherapy‐induced neutropenia might be a surrogate indicator of the biological activity of chemotherapy in patients with mCRPC. Background: Neutropenia is a common side effect associated with docetaxel use. We retrospectively investigated the association between chemotherapy‐induced neutropenia and survival in metastatic castration‐resistant prostate cancer (mCRPC) patients receiving first‐line docetaxel. Patients and Methods: Metastatic castration‐resistant prostate cancer patients treated with first‐line docetaxel, with known neutrophils value 10 days after first administration, were included in this retrospective analysis. Neutropenia was categorized in Grade 0 to 1 (G0‐1), Grade 2 to 3 (G2‐3), and Grade 4 (G4). Outcome measures were progression‐free survival (PFS) and overall survival (OS). Results: Eighty patients were analyzed. Median PFS was 5.4 months in patients with G0‐1 neutropenia, 6.9 months with G2‐3 neutropenia (hazard ratio [HR] vs. G0‐1, 0.69; 95% confidence interval [CI], 0.35‐1.35; P = .27) and 9.5 months with G4 neutropenia (HR vs. G0‐1, 0.30; 95% CI, 0.16‐0.57; P < .0001). Median OS was 11.6 months in patients with G0‐1 neutropenia, 25.5 months in patients with G2‐3 neutropenia (HR vs. G0‐1, 0.36; 95% CI, 0.16‐0.80; P = .012) and 39.3 months in patients with G4 neutropenia (HR vs. G0‐1, 0.19; 95% CI, 0.09‐0.41; P < .0001). In multivariate analysis, the occurrence of severe neutropenia showed a statistically significant association with OS (HR G4 vs. G0‐1, 0.14; 95% CI, 0.03‐0.67; P = .013; HR G2‐3 vs. G0‐1, 0.42; 95% CI, 0.11‐1.57; P = .20) and PFS (HR G4 vs. G0‐1, 0.28; 95% CI, 0.09‐0.86; P = .03; HR G2‐3 vs. G0‐1, 1.07; 95% CI, 0.38‐2.96; P = .90). Conclusion: Docetaxel‐induced neutropenia is associated with better survival of mCRPC.