Establishing and applying nomograms based on the 8th edition of the UICC/AJCC staging system to select patients with nasopharyngeal carcinoma who benefit from induction chemotherapy plus concurrent chemoradiotherapy

Objectives: The subgroups of patients with nasopharyngeal carcinoma (NPC) who benefit from induction chemotherapy plus concurrent chemoradiotherapy (IC+CCRT) remain unclear.

Materials and methods: We established prognostic nomograms for overall survival (OS) and disease-free survival (DFS), and validated the nomograms in 1230 patients with NPC and subgroup of 923 patients with locoregionally advanced NPC (LANPC). Three well-matched risk groups (i.e., low, intermediate and high risk) were created via recursive partitioning and 1-to-1 propensity score matching; IC+CCRT was compared with CCRT in each risk group.

Results: Histological type, T category, N category, plasma Epstein-Barr virus deoxyribonucleic acid (and the same factors plus age and neutrophil-lymphocyte ratio) were included in the nomograms for DFS (and OS). Both nomograms had higher c-indexes than the 7th edition staging system in both NPC/LANPC (all P-values≤0.010). The nomogram for OS also had a higher c-index in LANPC than the 8th edition staging system (P-value=0.052). OS was significantly different between all three risk groups in the individualized risk stratification (all P-values<0.001), while the 7th and 8th edition staging systems failed to clearly separate OS for stage II and III disease (P-value=0.415 and 0.347, respectively). IC+CCRT improved OS in intermediate and high risk patients with LANPC compared to CCRT alone (P-value<0.001 and P-value=0.002, respectively).

Conclusion: These prognostic nomograms could accurately guide treatment of individual patients with NPC. IC+CCRT could improve OS for patients with LANPC at intermediate to high risk.