Tumor Volume Predicts Local Control in Head and Neck Cancer

Abstract

Objective: Head and neck squamous cell carcinomas (HNSCC) are staged using the Tumor Node Metastasis (TNM) classification; however, limitations in its prognostic accuracy are recognized. The objective was to determine if pretreatment gross tumor volume (GTV) could be used as a predictor of primary site recurrence and therefore improve current staging. Method: A retrospective analysis of 53 patients treated with non laryngeal primary HNSCC, diagnosed between 2006 and 2007, was performed. Pretreatment GTV was calculated using Medical Imaging Interaction Toolkit (MITK) analysis of the patients’ staging radiology. The time to local recurrence and the 24-month actuarial local control rate were recorded. Results: The overall local control rate for the study group was 66%. Mean GTV was lower in patients without primary site recurrence, 8.47 cm3 (SD 6.42 cm3, range 2.52-8.36 cm3), compared with patients with primary site recurrence, 18.58 cm3 (SD 9.94 cm3, range 5.24-36.78 cm3). Patients with a GTV of <7.0 cm3 or >7.01 cm3 achieved control rates of 86.2% and 41.7%, respectively. Kaplan-Meier and coregression analyses demonstrate GTV as a prognostic indicator in oral cavity or oropharyngeal SCC, with GTV >7.01 cm3 having a significantly poorer local primary site control ( P = .009). Multivariate analyses for all possible prognostic factors for primary site recurrence was only significant for GTV ( P = .016). Conclusion: In oral cavity and oropharyngeal SCC pretreatment GTV is a prognostic indicator for local control, with multivariate analysis showing it to be more significant than T staging within this study. GTV can be easily calculated using MITK software, raising the possibility of its inclusion into the current TNM staging system.