Supplementary Material for: Clinicopathologic Features And Efficacy Of Induction Chemotherapy In Nasopharyngeal Carcinoma: Real-World Experience

Introduction: Nasopharyngeal carcinoma (NPC) accounts for 0.01% of all carcinomas, and 70% of patients have locally advanced disease with a poor prognosis. The mainstay therapy is chemoradiotherapy (CRT), and concurrent administration of platinum-based agents and irradiation provides high local control rates. However, induction (neoadjuvant) chemotherapy (ICT) prior to chemoradiotherapy is recommended for large tumors with a high tumor burden at category 1 level. For induction chemotherapy, platinum-based doublet or triplet combination regimens are recommended. Selected patients with high tumor burden at the time of diagnosis who did not receive induction chemotherapy before chemoradiotherapy were given adjuvant (consolidation) therapy after chemoradiotherapy. This multi-center study aims to share our experience in treatment of NPC and evaluate the factors associated with survival. Methods: The study included patients diagnosed with NPC who were followed and treated between 2008 and 2022. 142 patients from 6 centers were evaluated. The factors associated with disease-free survival (DFS) overall survival (OS) were evaluated. Results: The median age of our patients was 51 years (IQR: 16-81 years), and the male:female ratio was 2.5:1. A majority of patients (71%) had stage 3-4 disease. They had locally advanced disease, and 48 patients (34%) received induction chemotherapy. Twenty patients (14%) received adjuvant therapy. The median follow-up was 41 months (range, 2.7 to 175.1 months). The median DFS in NPC was 92.6 months (range, 71.9 to 113.3 months), with the 40th month DFS of 70.9%. The median OS was 113 months (range, 91 to 135 months), with the 40th month OS of 84.7%. Median DFS was 95.3 months (range, 64.2 to 126.4 months) in patients who received induction chemotherapy before CRT, which was longer than in the CRT-only group (p=0.6). DFS at the 40th month was 75.1% in patients treated with induction chemotherapy compared to 65.1% in the CRT-only group. Median OS was 117 months (range, 92 to 142 months) in patients receiving induction chemotherapy, which was longer than in the CRT-only group (p=0.4). OS at the 40th month was 86.7% in patients receiving ICT, but 83.6% in the CRT-only group. Conclusions: Both objective response rate (ORR) and survival were longer in patients who radiologically responded to chemoradiotherapy following induction chemotherapy. Non-response to induction chemotherapy is a negative predictive indicator. The role of induction chemotherapy in locally advanced NPC is increasing