The influence of serum sodium concentration on prognosis in resected non-small cell lung cancer.

Background: Hyponatremia is the most common electrolyte disorder and is a negative prognostic factor in several kinds of cancer. However, few reports have referred to hyponatremia in non-small cell lung cancer (NSCLC). In the present study, the authors examined the influence of preoperative serum sodium concentration on survival in completely resected NSCLC.

Methods: A total of 386 completely resected NSCLC patients were retrospectively analyzed.

Results: Kaplan-Meier survival curves showed that serum sodium concentration was a significant prognostic factor, and the log-rank statistical value was maximum (9.173, p = 0.002) when the cutoff value of serum sodium concentration was 139 mEq/L. The overall 5-year survival rate of the high-serum sodium concentration group (> 139 mEq/L) was 74.8% and that of the low-serum sodium concentration group (≤ 139 mEq/L) was 59.7%. Clinicopathological factors showed significant differences between the two groups for leukocyte count, neutrophil count, C-reactive protein, tumor size, and pleural invasion.

Conclusions: Low-serum sodium concentration, which was associated with tumor status and inflammation, had negative prognostic influence in completely resected NSCLC.