Plasma uric acid and tumor volume are highly predictive of outcome in nasopharyngeal carcinoma patients receiving intensity modulated radiotherapy

Hui Lin,Hong-Zhi Wang,Rui Sun,Wei-Han Hu,Nan Ge,Huan-Xin Lin

doi:10.1186/1748-717x-8-121

Abstract

BackgroundThe combined predictive value of plasma uric acid and primary tumor volume in nasopharyngeal carcinoma (NPC) patients receiving intensity modulated radiation therapy (IMRT) has not yet been determined.MethodsIn this retrospective study, plasma uric acid level was measured after treatment in 130 histologically-proven NPC patients treated with IMRT. Tumor volume was calculated from treatment planning CT scans. Overall (OS), progression-free (PFS) and distant metastasis-free (DMFS) survival were compared using Kaplan-Meier analysis and the log rank test, and Cox multivariate and univariate regression models were created.ResultsPatients with a small tumor volume (<27 mL) had a significantly better DMFS, PFS and OS than patients with a large tumor volume. Patients with a high post-treatment plasma uric acid level (>301 μmol/L) had a better DMFS, PFS and OS than patients with a low post-treatment plasma uric acid level. Patients with a small tumor volume and high post-treatment plasma uric acid level had a favorable prognosis compared to patients with a large tumor volume and low post-treatment plasma uric acid level (7-year overall OS, 100% vs. 48.7%, P <0.001 and PFS, 100% vs. 69.5%, P <0.001).ConclusionsPost-treatment plasma uric acid level and pre-treatment tumor volume have predictive value for outcome in NPC patients receiving IMRT. NPC patients with a large tumor volume and low post-treatment plasma uric acid level may benefit from additional aggressive treatment after IMRT.

Highlights

Nasopharyngeal carcinoma (NPC) is a common epithelial malignancy in southern China [1,2]
In the present study of a relatively large cohort of nasopharyngeal carcinoma (NPC) patients treated with intensity modulated radiation therapy (IMRT), we demonstrated that the post-treatment plasma uric acid level was a strong predictor of overall survival (OS), progression-free survival (PFS) and OS
Our study demonstrated that the 7-year distant metastasisfree survival (DMFS), PFS and OS rates in patients with small pretreatment tumor volumes (< 27 mL) were significantly higher than patients with pre-treatment tumor volumes equal to or larger than 27 mL

Summary

Introduction

Nasopharyngeal carcinoma (NPC) is a common epithelial malignancy in southern China [1,2]. Intensity modulated radiotherapy (IMRT) has gradually replaced two-dimensional conventional radiotherapy (2D-CRT) as the primary means of radiotherapy, and has led to superior locoregional control and improved long-term survival rates in NPC patients. Uric acid is the end product of purine metabolism. Radiotherapy is associated with increased oxidative damage to DNA [7]. A high plasma uric acid level may occur due to increased purine metabolism by xanthine oxidase, as a consequence of RNA-DNA breakdown in patients receiving radiotherapy [7]. The combined predictive value of plasma uric acid and primary tumor volume in nasopharyngeal carcinoma (NPC) patients receiving intensity modulated radiation therapy (IMRT) has not yet been determined

Methods

Results

Conclusion