Predicting osteoradionecrosis risk in patients with locoregionally advanced nasopharyngeal carcinoma undergoing concurrent chemoradiotherapy: the value of the CARWL index

Osteoradionecrosis is a severe complication that can arise in patients with nasopharyngeal carcinoma due to the aggressive nature of chemoradiotherapy treatment. The purpose of our study was to assess the utility of the recently introduced CARWL index, which integrates the C-reactive protein-to-albumin ratio (CAR) and significant weight loss (SWL), in predicting the risk of osteoradionecrosis (ORN) in patients with locoregionally advanced nasopharyngeal cancer (LA-NPC) undergoing concurrent chemoradiotherapy (CCRT). We conducted a retrospective cohort analysis on 304 patients with LA-NPC treated with CCRT. Patients were categorized into CARWL index groups based on CAR (cut-off: 3.0) and SWL (weight loss > 5% over the past six months): CARWL-0 (CAR < 3.0, SWL ≤ 5%), CARWL-1 (CAR < 3.0 with SWL > 5% or CAR ≥ 3.0 with SWL ≤ 5%), and CARWL-2 (CAR ≥ 3.0 and SWL > 5%). The primary endpoint was the incidence of ORN in each CARWL index group. At a median follow-up of 67.2 months, 28 patients (9.2%) developed ORN. The incidence of ORN was 2.1%, 9.4%, and 16.3% in the CARWL-0, CARWL-1, and CARWL-2 groups, respectively (P < 0.001). Multivariate analysis identified smoking status (HR: 2.58, P = 0.034), N-stage (HR: 1.96, P = 0.008), T-stage (HR: 1.84, P = 0.017), pre-CCRT tooth extraction status (HR: 5.81, P < 0.001), post-CCRT tooth extraction status (HR: 6.82, P < 0.001), mandibular V55.8 Gy (HR: 6.12, P < 0.001), and CARWL score (HR: 5.67, P = 0.002) as significant predictors of ORN. The CARWL index is a reliable predictive tool for evaluating the risk of ORN in LA-NPC patients undergoing CCRT. If further validated, its use in clinical settings could aid in the early identification of high-risk patients and enable the implementation of personalized preventive strategies.