Association of the neoadjuvant chemotherapy cycle with survival outcomes in patients with locoregionally advanced nasopharyngeal carcinoma: a propensity-matched analysis

Neoadjuvant chemotherapy (NAC) is widely used to treat locoregionally advanced nasopharyngeal carcinoma (NPC). To determine the optimal number of NAC cycles, we assessed the effect of NAC cycle on survival outcomes of locoregionally advanced NPC patients receiving NAC before concurrent chemotherapy and intensity-modulated radiotherapy. Clinical data from 1,188 non-metastatic NPC patients were retrospectively reviewed. All received ≥2 cycles of NAC added to concurrent chemoradiotherapy. Propensity score matching (PSM) was used to identify paired patients according to various covariates. In total, 297 pairs were selected. After a median follow-up time of 57 months (range: 7 to 104 months), the 5-year locoregional relapse-free survival, distant metastasis-free survival (DMFS), progression-free survival (PFS), and overall survival rates in patients treated with 2 cycles vs. 3 to 4 cycles of NAC were 91.3% vs. 87.2% (P=0.149), 93.3% vs. 88.5% (P=0.043), 88.7% vs. 81.7% (P=0.037), and 94.0% vs. 92.6% (P=0.266), respectively. On multivariate analysis, 2 cycles of NAC were associated with improved DMFS (hazard ratio, 0.499; P=0.038) and PFS (hazard ratio, 0.585; P=0.049). NAC cycle was an independent prognosticator of DMFS and PFS in univariate and multivariate analyses. Thus, 2 cycles of NAC appear sufficient, as additional cycles were not associated with added survival benefit for locoregionally advanced NPC.