Primary tumor inflammation in gross tumor volume as a prognostic factor for nasopharyngeal carcinoma patients

Purpose: The objective of this study is to investigate the prognostic value of primary tumor inflammation (PTI) in nasopharyngeal carcinoma (NPC) in the era of intensity-modulated radiation therapy (IMRT). Results: PTI was observed in 376/1708 (22.0%) patients, and was present in the sphenoid sinus in 289/376 (76.9%), in the nasal cavity in 27 (7.2%), and in both places in 60 (15.9%). The estimated 4-year local relapse-free survival (LRFS), diseasefree survival (DFS), overall survival (OS) and distant metastasis-free survival (DMFS) rates for PTI vs. non-PTI group were 89.2% vs. 96.1% (P < 0.001), 73.4% vs. 85.1% (P < 0.001), 85.0% vs. 92.1% (P < 0.001) and 83.6% vs. 91.4% (P < 0.001), respectively. After adjustment for these known prognostic factors, PTI was confirmed as an independent prognostic factor for LRFS (HR 2.152, 95% CI 1.318-3.516, P = 0.002), DFS (HR 1.581, 95% CI 1.204-2.077, P = 0.001) and DMFS (HR 1.682, 95% CI 1.177-2.402, P = 0.004). Conclusions: Primary tumor inflammation was identified as a strong prognostic factor for patients with NPC in the era of IMRT and should be considered when devising future treatment strategies aimed at improving survival in NPC patients. Materials and Methods: Data on 1708 patients with nonmetastatic, histologically-confirmed NPC treated with IMRT between November 2009 and February 2012 at Sun Yat-Sen University Cancer Center were retrospectively reviewed. Patient survival between PTI and non-PTI groups were compared.