Abstract
BACKGROUND/AIM: This study investigated the prognostic value of serum uric acid (SUA) levels after definitive radiotherapy (RT) in head and neck cancer (HNC). PATIENTS AND METHODS: This retrospective study included patients with HNC undergoing definitive RT between January 2008 and February 2019. SUA levels were measured pre- and post-RT. Survival outcomes were analyzed using the Kaplan-Meier method, log-rank tests, and multivariable Cox regression. The optimal post-RT SUA cut-off (4.6 mg/dl) was determined via ROC analysis. RESULTS: A total of 185 patients were analyzed, with a median follow-up of 63.3 months. The mean pre-treatment SUA level was 5.4 mg/dl, which decreased to 5.2 mg/dl post-treatment, though the difference was not statistically significant (p=0.326). A post-treatment SUA cut-off of 4.6 mg/dl demonstrated discriminatory ability for distant metastasis-free survival (DMFS) but was not predictive of overall survival or locoregional relapse-free survival (LRFS). Kaplan-Meier analysis showed that patients with post-treatment SUA ≥4.6 mg/dl had significantly poorer DMFS than those with lower levels [hazard ratio (HR)=1.25, 95% confidence interval (CI)=1.02-1.53; p=0.004]. Multivariable analysis confirmed post-treatment SUA ≥4.6 mg/dl (HR=5.01, p=0.010), HPV-negative oropharyngeal tumors (HR=5.68, p=0.025), and Stage IV disease (HR=4.10, p=0.020) as independent prognostic factors for DMFS. CONCLUSION: Post-treatment SUA levels may serve as a potential marker for predicting metastasis following RT in HNC.