Preoperative serum sodium is associated with cancer-specific survival in patients with upper urinary tract urothelial carcinoma treated by nephroureterectomy

Objectives To assess the impact of preoperative serum sodium concentration on the prognosis of patients with upper urinary tract urothelial carcinoma treated by nephroureterectomy. Methods The clinical records of 139 patients treated for upper urinary tract urothelial carcinoma by nephroureterectomy were retrospectively reviewed. Recurrence-free and cancer-specific survival curves were calculated using the Kaplan-Meier method, with the difference between curves evaluated using the log-rank test. A multivariate analysis was carried out by Cox's proportional hazard model to identify prognostic factors. Results The median (range) follow-up time was 27 (1-139)months. The median (range) preoperative serum sodium was 141 (134-147) mEq/L. Five-year cancer-specific survival estimates for patients above and below the median preoperative serum sodium were 81.7% (95% confidence interval: 68.7-89.7) and 50.6% (95% confidence interval: 30.3-67.8), respectively. In the multivariate analysis, preoperative sodium concentration, pathological T stage, and lymphovascular invasion were independent and significant prognostic factors for cancer-specific survival. A prognostic model of risk classification for cancer-specific survival involving these parameters was developed, and 5-year cancer-specific survival estimates were 29.9% (95% confidence interval: 14.5-47.0) for the poor risk group (hazard ratio 19.95 [95% confidence interval: 8.5-46.6]; P<0.001), 81.6% (95% confidence interval: 55.2-93.3) for the intermediate risk group (hazard ratio 5.70 [95% confidence interval: 1.27-25.5]; P=0.022) and 97.9% (95% confidence interval 85.9-99.7) for the favorable risk group. Conclusion These findings suggest for the first time that a low preoperative sodium level predicts a poor survival in upper urinary tract urothelial carcinoma patients treated by nephroureterectomy.