Development and Internal Validation of a Prediction Model for Nasopharyngeal Carcinoma: Using BMI and Inflammatory Response for Deciding Sequence of Chemotherapy

PURPOSE Concurrent chemoradiotherapy followed by adjuvant chemotherapy (CRT-AC) and induction chemotherapy followed by concurrent chemoradiotherapy (IC-CRT) are among the best treatments in nasopharyngeal carcinoma (NPC). This study aimed to develop a model for deciding the sequence of chemotherapy in NPC. METHODS Data were separated into two cohorts. The CRT-AC cohort had 295 patients, while the IC-CRT cohort had 112. The predictors were standard factors with BMI and neutrophil-lymphocyte ratio (NLR) to predict overall survival (OS). A flexible parametric survival model was used. RESULTS A total of 132 (44.7%) and 72 patients (64.3%) died in the CRT-AC and IC-CRT cohorts, respectively. The predictors in the final models were age, sex, T, N, NLR, and BMI. The models of OS for CRT-AC and IC-CRT had concordance indices of 0.689 and 0.712, respectively, with good calibration curves. When changing the burden of disease along with NLR and BMI, we found that CRT-AC was not significantly different OS from IC-CRT when low NLR (<3) and high burden of disease (T3N3). By contrast, CRT-AC was remarkably more effective when there were high levels of NLR (≥3) and BMI (≥25) with any burden of disease (anyT anyN). CONCLUSION With additional BMI and NLR in model, it could be easier to decide between CRT-AC and IC-CRT in countries with limited health care resources.