Introduction: The aim of this study was to evaluate the prognostic value of hyponatremia in patients with castration-resistant prostate cancer (CRPC) undergoing docetaxel chemotherapy.
Patients and methods: We retrospectively assessed 186 patients who received docetaxel chemotherapy in addition to androgen deprivation for CRPC between 2005 and 2015. We stratified the patients according to their pre-chemotherapy serum sodium level. Hyponatremia was defined as sodium < 135 mmol/L. A Cox proportional regression model was used to estimate overall survival (OS).
Results: The median sodium level was 139 mmol/L (interquartile range, 137-141 mmol/L). Hyponatremia was detected in 13 (6.9%) patients. One-half of the patients died during the studied period. The presence of hyponatremia was associated with a decreased probability of OS (hazard ratio, 2.5; 95% confidence interval, 1.0-6.3; P = .04) in univariate analysis. These findings could not be confirmed in the multivariable OS model (P = .21).
Conclusion: We observed an association between hyponatremia and worse survival outcomes in our patients with CRPC undergoing docetaxel chemotherapy. However, further well-designed studies with full workup of hyponatremia are needed to validate these findings and to identify the underlying causes for this association in patients with CRPC.
Keywords: Hyponatremia; Prognostic; Prostate cancer; Survival.
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