Therapeutic evaluation of induction chemotherapy for locoregionally advanced nasopharyngeal carcinoma with low-risk N stage -a multicenter retrospective study from non-endemic region of China

Background: There are conflicting results regarding the role of IC in T3-4N0-1 NPC patients from endemic area of China. Therefore, it is worth verifying the consistency of study between endemic area and non-endemic area for NPC and providing treatment guidance for non-endemic NPCs. We conducted a multicenter real-world study to investigate the value of adding IC to CCRT for T3-4N0-1 NPC in Northwest of China. Methods Data was extracted in three hospitals from Northwest China between May 1, 2010 and August 30, 2018. The Kaplan-Meier method was used to estimate the endpoints, survival curves were compared using the log-rank test. Initial propensity matching was conducted with a 1:1 match of IC + CCRT to CCRT. The primary endpoint of this study was overall survival (OS). Results A total of 108 patients with staging T3-4N0-1 were included in this study. The median follow-up time was 50 months (range: 6-118 months). IC followed by CCRT had trend to improve OS compared with CCRT (89.5% vs.77.6%, HR:0.41, 95%CI:0.16–1.04, P = 0.100). After analysis of well-balanced propensity score-matched cohort, IC followed by CCRT provided superior OS than CCRT alone. Adjusted 4-year OS was 89.5% for IC followed by CCRT vs. 71.1% for CCRT (HR:0.30, 95%CI:0.11–0.80, P = 0.027). No significant differences were detected in side effects between two groups. Conclusion This study implied IC followed by CCRT improved OS in patients with T3-4N0-1M0 NPC from Northwest China compared with CCRT. However, prospective studies with large sample are warranted to confirm the result.