This study aimed to explore the selection of induction chemotherapy (IC) cycles for stage N3 nasopharyngeal carcinoma (NPC). We employed propensity score matching (PSM) to categorize patients into 3-cycle and 4-cycle IC groups (IC = 3 and IC = 4). The log-rank and chi-squared tests were used respectively to evaluate the differences in survival and acute toxicities. Survival outcomes including overall survival (OS), progression-free survival (PFS), distant metastasis-free survival (DMFS), and locoregional relapse-free survival (LRRFS) were evaluated among the two groups. After PSM, each group comprised 99 patients. The IC = 4 group exhibited markedly improved survival outcomes compared with the IC = 3 group. Multivariate analysis revealed that pre-EBV DNA was an independent risk factor affecting PFS and DMFS. For high-risk patients with pre-EBV DNA ≥ 7800 copies/ml, the IC = 4 group demonstrated greater survival compared to the IC = 3 group. Among low-risk patients with pre-EBV DNA < 7800 copies/ml, both groups showed comparable survival outcomes. In terms of acute adverse reactions, the IC = 4 group experienced higher incidences, particularly with grade 2-4 alanine transaminase elevation and thrombocytopenia. For stage N3 NPC, pre-EBV DNA could be a powerful predictor for guiding the selection of IC cycles. The IC = 4 regimen is probably more beneficial to high-risk patients due to superior survival, while for low-risk patients, the IC = 3 regimen may be sufficient.
Keywords: Chemotherapy cycle; Induction chemotherapy; Nasopharyngeal carcinoma; Pre-treatment Epstein-Barr virus DNA.
© 2024. The Author(s).