Metabolic Signatures in Lung Cancer: Prognostic Value of Acid-Base Disruptions and Serum Indices

One characteristic of tumor cells is the increased anaerobic metabolism through glycolysis leading to an acidic environment of the tumor. This acidity is linked to tumor progression, invasion and metastasis, besides stimulated survival pathways in the malignant cells. The aim of our analysis is to investigate the role of systemic acid-base parameters such as the pH, bicarbonate, baseexcess and lactate in lung cancer patients. Furthermore, alterations in electrolytes and hemoglobin were investigated regarding their impact on overall survival. Data of 937 non-small-cell lung cancer (NSCLC) patients, who underwent anatomic video-assisted thoracoscopic surgery (VATS) resection, was collected in a prospectively maintained database and analyzed. To minimize confounding effects and due to the retrospective study design, we decided to use data from the first arterial blood gas analysis during surgery and the most recent lab results prior to surgery. We found significant correlations between low systemic bicarbonate (<20 mEq/L) and overall survival (p = 0.006). Hyponatremia (<135 mmol/L) correlated with lower 5-year overall survival (p = 0.004) and decreased disease-free survival (p = 0.017). Hypochloremia (<98 mmol/L) was linked to reduced overall survival (p = 0.003) and hypocalcemia (<1.15 mmol/L) with worse disease-free survival (p = 0.015). Hemoglobin under 12 g/dL for women and 13 g/dL for men was associated with poorer outcomes (p < 0.001). Other acid-base parameters such as the pH (p = 0.563), baseexcess (BE) (p = 0.290) and lactate (p = 0.527) did not show significant differences in overall or disease-free (pH: p = 0.130; BE: p = 0.148; lactate: p = 0.418) survival. Systemic bicarbonate, sodium, calcium, chloride and hemoglobin levels were found as prognostic markers and possible therapeutic targets to improve overall survival. Further investigations are necessary to develop therapeutic strategies.