Purpose: To investigate the role of induction chemotherapy (IC) in lymph node-positive (LN-positive) stage III nasopharyngeal carcinoma (NPC) receiving concurrent chemoradiotherapy (CCRT).
Methods: In total, 627 patients with newly diagnosed LN-positive stage III NPC receiving CCRT or IC plus CCRT were included. The primary endpoint was progression-free survival (PFS). Propensity-score matching (PSM) was conducted to balance the intergroup covariates. Kaplan-Meier method with log-rank test was employed to compare survival curves. Subgroup analyses were conducted based on baseline characteristics.
Results: After 1:1 PSM, 414 patients were identified (207 patients per group). Compared with CCRT, IC plus CCRT provided better survival (5-year PFS 88.4% vs. 78.6%, P = 0.01; overall survival [OS] 94.8% vs. 85.3%, P = 0.003; and distant metastasis-free survival [DMFS] 93.1% vs. 85.6%, P = 0.03). The IC beneficial effects on PFS were mainly present in patients with grade 2-3 ENE, elevated serum lactate dehydrogenase (LDH > 170U/L), and N2 disease. Patients with grade 2 CNN had comparable PFS benefits to those with grade 0-1 CNN. For patients with grade 0-1 ENE combined with LDH ≤ 170U/L, survival between the two groups was similar with 5-year PFS 93.6% vs. 90.4% (P = 0.50), OS 94.2% vs. 93.0% (P = 0.72), and DMFS 98.6% vs. 97.7% (P = 0.98).
Conclusion: Adding IC before CCRT improved survival in LN-positive stage III NPC patients. Additional IC did not provide better survival for patients with grade 0-1 ENE combined with LDH ≤ 170U/L and could be avoided in this population. CNN may not be a good risk factor for tailoring a personalized treatment plan.
Keywords: Cervical nodal necrosis; Concurrent chemoradiotherapy; Extranodal extension; Head and neck cancers; Induction chemotherapy; Lactate dehydrogenase; Nasopharyngeal carcinoma; Prognostication.
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