Prognostic significance of the baseline serum uric acid level in non-small cell lung cancer patients treated with first-line chemotherapy: a study of the Turkish Descriptive Oncological Researches Group.

Non-small cell lung cancer (NSCLC) is one of the most common cancers. Most of the patients are inoperable at the time of diagnosis, and the prognosis is poor. Many prognostic factors have been identified in prior studies. However, it is not clear which factor is more useful. In this study, we investigated whether uric acid, the last breakdown product of purine metabolism in humans, has a prognostic significance in advanced NSCLC. A total of 384 NSCLC patients at stage IIIB/IV and who did not meet exclusion criteria were included in this retrospective cross-sectional study. The patients' serum uric acid levels before first-line chemotherapy and demographic (age, gender, smoking), clinical (performance status, weight loss, disease stage, first-line treatment regimen), laboratory (hemoglobin, lactate dehydrogenase), and histologic (histologic type, tumor grade) characteristics were recorded. First, a cut-off value was determined for serum uric acid level. Then, the patients were stratified into four groups (quartiles) based on their serum uric acid levels. Descriptive statistics, univariate and multivariate analyses, and survival analyses were used. Majority of the patients were males, smokers and metastatic at time of diagnosis and had history of weight loss and adenocarcinoma upon pathological examination. The serum uric acid levels of all patients were determined as 4.9±2.9 (range 1.9-11.3). The patients were stratified according to quartiles of serum uric acid concentration with cutoff values defined as <3.08 mg/dL (lowest quartile, Group 1), 3.09-5.91 mg/dL (Group 2), 5.92-7.48 mg/dL (Group 3), and >7.49 mg/dL (highest quartile, Group 4). Among the patients who had serum uric acid levels over 7.49, it was observed that those who also had squamous cell carcinoma had a greater rate of brain metastasis, a shorter time lapse until brain metastasis, and lower overall survival rate. It can be assumed that NSCLC patients who had histologically shown squamous cell carcinoma display brain metastasis and poor prognosis. It can be recommended to repeat this study with larger patient series including immunohistochemical, molecular, and wider laboratory investigations.