The association between RDW and survival of patients with squamous cell carcinoma of the tongue. Simple, cheap and convenient?

Abstract

The purpose of this study was to evaluate the prognostic impact of red-cell distribution width (RDW) on the overall survival (OS) of patients with squamous cell carcinoma (SCC) of the tongue. Development of cancer is connected with an ongoing inflammatory process which is reflected by laboratory indices, such as RDW that can be used as prognostic tools. The study group consists of 74 consecutive patients treated with radical radiotherapy or chemo-radiotherapy for SSC of the tongue at one institution between 2005-2014. RDW was assessed based on routine blood tests done before the start of the treatment. ROC curve was applied to assess value of RDW in prediction of OS, and a cut-off value for further tests was obtained using the Younden index. The survival analysis was performed using the Kaplan-Meier method, log-rank testing and Cox regression model. The AUC for RDW in ROC analysis was 0.703, and the optimal cut-off value was 13.5%. 5-year OS was significantly lower in patients with RDW ≥ 13.5% compared with patients with RDW < 13.5% (67% vs. 26%, p-value = 0.0005). Additionally, high RDW was associated with a greater odds ratio for 5-year OS in a multivariate Cox proportional hazards regression analysis (3.43, 1.62-7.25; p = 0.001). Our study demonstrated that pre-treatment RDW ≥ 13,5% is an indicator of poor overall survival in patients with SCC of the tongue. Since RDW is a cheap and convenient marker, usually routinely assessed during complete blood count tests, it could be further used as an additional prognostic tool in patients with tongue cancers.