Pretreatment Maximal Standardized Uptake Value of the Primary Tumor Predicts Outcome to Radiotherapy in Patients with Pharyngeal Cancer

Abstract

This study aimed to investigate whether the combination of clinical information, tumor volume and pretreatment SUVmax at the primary tumors might improve the prognostic stratification in pharyngeal cancer (PC) patients treated with radiotherapy (RT). Sixty-two patients with PC (35 oropharynx; 27 hypopharynx) treated with RT were enrolled in this retrospective analysis. All patients received pretreatment FDG- PET or PET/CT. The primary tumor relapse-free survival (PRFS) was calculated according to different variables. The median values of the SUVmax for the primary tumors (SUVp-max) and the gross tumor volume (GTVp) were used to divide patients into two groups. Independent prognosticators were identified by the Cox regression analysis. In this study, the median SUVp-max and GTVp was 11 and 15.5 ml. Patients having tumors with SUVp-max > 11 had a significantly inferior 2-year PRFS (41% vs. 75%, p = 0.003) compared with patients having lower uptake tumors. Multivariate analysis of the PRFS showed two prognostic factors: SUVp-max > 11 (p = 0.04, hazard ratio = 2.67) and GTVp > 15.5 ml (p = 0.03, hazard ratio = 2.88). For patients with a GTVp less than 15.5 ml, there was a more significant impact of SUVmax-p on their PRFS compared to that for those with large ones. We disclosed a higher pretreatment SUVp-max is a predictor for primary recurrence in PC patients treated with RT, particularly for those with smaller tumor volumes. Patients with a large tumor volume or a higher SUVp-max should be considered for requiring more aggressive treatment approaches.