The effect of adjuvant chemotherapy and early tumor regression on the outcome of nasopharyngeal cancer patients treated with concurrent chemoradiotherapy.

OBJECTIVES: We assessed the role of adjuvant chemotherapy (ACT) in patients with advanced nasopharyngeal carcinoma treated with concurrent chemoradiotherapy (CCRT) and investigated the prognostic factors for recurrence and survival. MATERIALS AND METHODS: Between January 2008 and January 2018, 88 non-metastatic nasopharyngeal carcinoma patients treated with CCRT and with or without ACT in two institutions were retrospectively reviewed. The initial tumor response evaluation was performed 1 month after CCRT completion. Survival analysis was performed for factors such as initial tumor regression, ACT and other clinical factors. Subgroup analysis was performed for the four-group categorized according to tumor regression and ACT (CR with/without ACT, non-CR with/without ACT). RESULTS: Complete response (CR) 1 month after CCRT was a favorable prognosticator for progression-free survival (PFS) (hazard ratio [HR] 3.16, 95% confidence interval [CI] 1.02-9.85, p = 0.046) and overall survival (OS) (HR 3.19, 95% CI 1.14-8.93, p = 0.027). Also, ACT was an independent factor for PFS (HR 0.38, 95% CI 0.15-0.98, p = 0.047) and OS (HR 0.37, 95% CI 0.13-0.99, p = 0.047). In subgroup analysis, the CR after CCRT followed by ACT group showed significantly higher locoregional recurrence-free survival (p = 0.02), OS (p = 0.003), distant-metastasis free survival (p = 0.07), and PFS (p = 0.01) than the other three groups. CONCLUSION: Tumor regression 1 month after CCRT, and administration of ACT identified as an independent prognosticator for PFS and OS in this study. Even patients who show early tumor regression after CCRT may benefit from ACT. Further randomized trials should define the role of ACT in patients with nasopharyngeal cancer who achieved CR after CCRT.