Prechemoradiotherapy number of natural teeth as a prognostic factor in patients with locally advanced nasopharyngeal cancer: a retrospective observational study

Abstract

Objective: This study evaluated the prognostic value of the pretreatment number of natural teeth on progression-free survival and overall survival in patients with locally advanced nasopharyngeal carcinoma treated with concurrent chemoradiotherapy. Methods: We retrospectively analyzed 248 patients with locally advanced nasopharyngeal carcinoma treated with intensity-modulated radiotherapy–based concurrent chemoradiotherapy and adjuvant chemotherapy between June 2010 and December 2021. The number of natural teeth was assessed before concurrent chemoradiotherapy. A receiver operating characteristic curve analysis was performed to identify the optimal number of natural teeth threshold predictive of overall survival and progression-free survival. Results: The optimal cutoff value for the number of natural teeth was 19.5 (area under the curve: 70.6%). Patients were grouped into those with a number of natural teeth <20 (n = 76) and those with a number of natural teeth ≥20 (n = 172). The number of natural teeth ≥20 group had significantly improved overall survival (not reached vs. 71.0 months; p < 0.001) and progression-free survival (117 vs. 38.0 months; p < 0.001). Multivariate analysis confirmed the number of natural teeth <20 as an independent predictor of worse outcomes. Conclusions: A pretreatment number of natural teeth <20 independently predicts poorer survival in patients with locally advanced nasopharyngeal carcinoma receiving concurrent chemoradiotherapy, suggesting that the number of natural teeth may serve as a simple, accessible prognostic biomarker in head and neck oncology.