Association between tumor volume reduction and treatment outcomes in nasopharyngeal carcinoma treated with PCE-based induction chemotherapy and concurrent chemoradiotherapy

BACKGROUND: This study aimed to evaluate the association between total tumor volume reduction rate (VRR) and treatment outcomes in patients with locoregionally advanced nasopharyngeal carcinoma (LA-NPC) treated with paclitaxel, carboplatin, and cetuximab (PCE)-based induction chemotherapy (IC) followed by concurrent chemoradiotherapy (CCRT). METHODS: Patients with LA-NPC who were planned to undergo IC-PCE followed by CCRT between September 2017 and December 2024 were included. Overall survival (OS) and progression-free survival (PFS) were calculated, and factors associated with PFS were evaluated. VRR was dichotomized based on a cutoff value derived from receiver operating characteristic curve analysis. RESULTS: In total, 43 consecutive patients with LA-NPC (median age, 56 years) were included. The median follow-up time was 48 months (Interquartile Range, 34-69). The 3-year OS and PFS were 95.3% and 76.1%, respectively. A total of 12 PFS events were observed, including locoregional recurrence (n = 3), distant metastasis (n = 6), both (n = 1), and death (n = 2). In multivariable analysis adjusted for cStage (Union for International Cancer Control 9th edition), a high VRR (cutoff value, 48.6%) was identified as a significant factor associated with improved PFS (hazard ratio, 0.21; 95% confidence interval, 0.06-0.70; p = 0.01). CONCLUSION: VRR was associated with PFS, suggesting that tumor shrinkage following IC-PCE may serve as a prognostic marker.