Higher serum nitrate levels are associated with poor survival in lung cancer patients

Angiogenic factors induce tumour growth and angiogenesis which leads to tumour metastasis and a poor survival rate. This study aimed to assess the possible roles of nitric oxide (NO) and vascular endothelial growth factor-A (VEGF-A) in the overall survival of patients with late stage lung cancer.

The study was carried out with primary lung carcinoma patients (n=31) and healthy controls (n=15). Pre- and post-cisplatin-based chemotherapy serum nitrite/nitrate levels were measured as nitrite after enzymatic conversion followed by Griess reaction and serum VEGF-A analysis was performed using ELISA. After patient follow-up, survival rates were calculated by using the Kaplan-Meier method [Dudek et al. Cancer Invest 2005; 23(3):193-200].

The serum nitrite/nitrate and VEGF-A levels of lung cancer patients and the control group were 93.7+/-48.9 and 63.7+/-32.2 microM (p=0.018), and 620+/-491 and 255+/-157 pg/mL (p=0.001), respectively. High nitrite/nitrate (>67.2 microM) concentration had statistically significant effects on overall survival (Cox analysis, p=0.026). The overall survival of the lung cancer patients with higher serum nitrate concentrations was significantly less than the ones with lower serum nitrite/nitrate (Kaplan-Meier survival functions test, log rank significance=0.0007).

Our results suggest that having a high serum nitrite/nitrate concentration is a strong indicator of poor survival for late stage lung cancer patients. However, this conclusion deserves to be elucidated further by using a larger sample size.