Retrospective Analysis of the Survival Benefit of Induction Chemotherapy in Stage IVa-b Nasopharyngeal Carcinoma

<div><p>Purpose</p><p>The value of adding induction chemotherapy to chemoradiotherapy in locoregionally advanced nasopharyngeal carcinoma (LA-NPC) remains controversial, yet high-risk patients with LA-NPC have poor outcomes after chemoradiotherapy. We aimed to assess the survival benefits of induction chemotherapy in stage IVa-b NPC.</p><p>Patients and Methods</p><p>A total of 602 patients with stage IVa-b NPC treated with intensity-modulated radiation therapy (IMRT) and concurrent chemotherapy with or without induction chemotherapy were retrospectively analyzed. Overall survival (OS), locoregional relapse-free survival (LRFS), distant metastasis-free survival (DMFS) and progression-free survival (PFS) were evaluated using the Kaplan-Meier method, log-rank test and Cox regression analysis.</p><p>Results</p><p>In univariate analysis, 5-year OS was 83.2% for induction chemotherapy plus concurrent chemotherapy and 74.8% for concurrent chemotherapy alone, corresponding to an absolute risk reduction of 8.4% (<i>P</i> = 0.022). Compared to concurrent chemotherapy alone, addition of induction chemotherapy improved 5-year DMFS (83.2% vs. 74.4%, <i>P</i> = 0.018) but not 5-year LRFS (83.7% vs. 83.0%, <i>P</i> = 0.848) or PFS (71.9% vs. 66.0%, <i>P</i> = 0.12). Age, T category, N category, chemotherapy strategy and clinical stage were associated with 5-year OS (<i>P</i> = 0.017, <i>P</i> = 0.031, <i>P</i> = 0.007, <i>P</i> = 0.022, <i>P</i> = 0.001, respectively). In multivariate analysis, induction chemotherapy plus concurrent chemotherapy was an independent favorable prognostic factor for OS (HR, 0.62; 95% CI, 0.43–0.90, <i>P</i> = 0.012) and DMFS (HR, 0.57; 95% CI, 0.38–0.83, <i>P</i> = 0.004). In subgroup analysis, induction chemotherapy significantly improved 5-year DMFS in stage IVa (86.8% vs. 77.3%, <i>P</i> = 0.008), but provided no significant benefit in stage IVb.</p><p>Conclusions</p><p>In patients with stage IVa-b NPC treated with IMRT, addition of induction chemotherapy to concurrent chemotherapy significantly improved 5-year OS and 5-year DMFS. This study provides a basis for selection of high risk patients in future clinical therapeutic trials.</p>