Prognostic value of the distance between the primary tumor and brainstem in the patients with locally advanced nasopharyngeal carcinoma

Abstract

Background: Brainstem dose limitations influence radiation dose reaching to tumor in the patients with locally-advanced nasopharyngeal cancer (NPC). Methods: A retrospective analysis of the prognostic value of the distance between the primary tumor and brainstem (Dbs) in 358 patients with locally-advanced NPC after intensity-modulated radiation therapy (IMRT). Receiver operating characteristic (ROC) curves were used to identify the cut-offvalue to analyze the impact of Dbs on tumor dose coverage and prognosis. Results: The three-year overall survival (OS), local relapse-free survival (LRFS), distant metastasis-free survival (DMFS), and disease-free survival (DFS) were 88.8 vs. 78.4% (P=0.007), 96.5 vs. 91.1% (P=0.018), 87.8 vs. 79.3% (P=0.067), and 84.1 vs. 69.6% (P=0.002) for the patients with the Dbs>4.7 vs. ≤ 4.7mm, respectively. ROC curves revealed Dbs (4.7mm) combined with American Joint Committee on Cancer (AJCC) T classification had a significantly better prognostic value for OS (P<0.05). Conclusions: Dbs (≤4.7mm) is an independent negative prognostic factor for OS/LRFS/DFS and enhances the prognostic value of T classification in the patients with locally-advanced NPC.