The Pre-Treatment C-Reactive Protein Represents a Prognostic Factor in Patients with Oral and Oropharyngeal Cancer Treated with Radiotherapy

The purpose of the present study was to evaluate the prognostic significance of the pre- treatment C-reactive protein (CRP) level in a cohort of 503 patients with oral and oropharyngeal cancer treated at a tertiary academic center between 2000 and 2017. Cancer-specific survival (CSS), overall survival (OS) and loco-regional control (LC) were calculated using Kaplan-Meier analysis. To evaluate the prognostic value of the CRP level for the clinical endpoints, univariate and multivariate Cox regression models were applied. The median follow-up period was 61 months. Patients were divided into elevated CRP (≥5 mg/L) and normal CRP groups, according to pre-treatment plasma levels. An increased CRP level was significantly associated with shorter CSS (p < 0.001, log-rank test), as well as with shorter OS (p < 0.001, log-rank test) and loco-regional control (p = 0.001, log-rank test). In addition, multivariate analysis identified CRP as an independent predictor for CSS (hazard ratio (HR) 1.59, 95% confidence interval (CI) 1.08–2.35; p = 0.020) as well as for OS (HR 1.62, 95%CI 1.17–2.24; p = 0.004) and LC (HR 1.50, 95%CI 1.06–2.14; p = 0.023). In subgroup analysis, Kaplan Meier curves revealed that an elevated pre-treatment CRP level was a consistent prognostic factor for poor CSS (p = 0.003, log-rank test), OS (p = 0.001, log-rank test), and LC (p = 0.028, log-rank test) in patients treated with definitive (chemo-) radiotherapy, whereas a significant association in patients undergoing surgery and postoperative radiotherapy was not detected. The pre-treatment CRP level seems to represent a prognostic factor for CSS, OS, and LC in patients with oral and oropharyngeal cancer, particularly in those treated with definitive (chemo-) radiotherapy. Additional large-scale prospective studies are warranted to confirm and extend our findings.