The Comprehensive Repair–Inflammation Index (CRII) predicts tooth extraction after chemoradiotherapy: a continuous and nonlinear modeling analysis

Abstract

Tooth extraction (TE) after chemoradiotherapy is common in locally advanced nasopharyngeal carcinoma (LA-NPC), yet its determinants remain unclear. We evaluated the association between the Comprehensive Repair–Inflammation Index (CRII), reflecting systemic inflammation and host repair capacity, and TE risk after concurrent chemoradiotherapy (CCRT). Methods: We conducted a retrospective analysis of 354 patients with LA-NPC treated with definitive CCRT. The primary endpoint was post-treatment TE (none vs. ≥1). CRII was calculated from pre-treatment laboratory parameters and analyzed continuously, with a breakpoint identified via segmented regression. Logistic regression and restricted cubic splines were used. Multivariable models adjusted for clinical variables and mandibular dosimetric parameters (mean dose, V50, V60). Results: TE occurred in 70.1% of patients. CRII was significantly higher in those with TE (147.5 vs. 122.0; p