3660 - Evaluation of Adjuvant Chemotherapy after Induction Chemotherapy and Concurrent Chemoradiotherapy in Locoregionally Advanced Nasopharyngeal Carcinoma Patients: A Propensity Score-Matched Analysis

Y. He¹, Y. Li², Q. Tang¹, S. Ma¹, Z. Xiong¹, and Y. Huang¹; ¹Department of Cancer Center, Second Affiliated Hospital, Chongqing Medical University, Chongqing, China, Chongqing, China, ²Department of radiotherapy, West China Hospital, Sichuan University, Chengdu, China, Sichuan, China

Purpose/Objective(s): The clinical value of adjuvant chemotherapy (AC) after induction chemotherapy (IC) and concurrent chemoradiotherapy (CCRT) in locoregionally advanced nasopharyngeal carcinoma (LA-NPC) is still controversial. The purpose of this study is to explore the role of AC after IC-CCRT in LA-NPC. Materials/

Methods: Patients with stage II- IVb treated with IC-CCRT-AC or IC-CCRT were retrospectively analyzed. The propensity score-matched (PSM) method was conducted to balance variables. Univariate and multivariate cox regression analysis was used to find independent prognostic factors. The primary outcome was disease-free survival (DFS).
Results: A total of 1050 patients were included for analysis. The AC regimen included 2-3 cycles of TPF (docetaxel, cisplatin and 5-fluorouracil), GP (gemcitabine and cisplatin), and PF (cisplatin and 5-fluorouracil). After PSM analysis, 445 pairs were obtained. With a median follow-up of 50 months, we found that patients treated with IC-CCRT-AC showed worse prognosis than those treated with IC - CCRT in DFS (IC-CCRT-AC vs. IC-CCRT, 80.4% vs 85.4%, HR 1.657, 95%Cl 1.196-2.296, P = 0.002) and locoregional relapse-free survival (89.2% vs 93.7%, HR 1.983, 95%Cl 1.244- 3.162, P = 0.003). The distant metastasis-free survival was insignificant (90.1% vs 90.3%, HR 1.18, 95%Cl 0.775- 1.797, P = 0.4). Patients treated with IC-CCRT-AC showed significantly higher incidences of neutropenia (19.3% vs. 17.3%, P ?0 .001) than those treated with IC-CCRT. Multivariate analysis showed that the modality of therapy, sex, tumor classification, lymph node classification, anemia and aspartate transaminase increased were significant prognostic factors for DFS.
Conclusion: The addition of AC (cisplatin-based chemotherapy) to IC-CCRT did not show survival benefit for patients with stage II- IVb NPC.