Neoadjuvant chemotherapy followed by concurrent chemoradiotherapy versus concurrent chemoradiotherapy followed by adjuvant chemotherapy in locally advanced nasopharyngeal carcinoma

Background: Concurrent chemoradiotherapy followed by adjuvant chemotherapy (CCRT-AC) is currently recommended as the standard treatment for locally advanced nasopharyngeal carcinoma (LA-NPC). Neoadjuvant chemotherapy followed by concurrent chemoradiotherapy (NAC-CCRT) is an alternative strategy for decreasing tumor size and controlling micrometastases before main treatment. The aim of this study was to investigate and compare survival outcomes between LA-NPC patients treated with CCRT-AC and those treated with NAC-CCRT. Methods: This retrospective cohort study included consecutive histologically confirmed LA-NPC patients that were treated with NAC-CCRT or CCRT-AC at Siriraj Hospital during the March 2010 to October 2014 study period. CCRT in both protocols consisted of 3-week cycles of cisplatin 100 mg/m² with concurrent radiotherapy. Either NAC or AC consisted of 3-week cycles of cisplatin on day 1 and fluorouracil/leucovorin on days 1-4 for a maximum three cycles. The primary endpoint was 5-year overall survival (OS). Flexible parametric survival analysis was used, because the proportional hazards assumption of Cox regression was violated. Results: Of the 266 LA-NPC patients that received treatment during the study period, 79 received NAC-CCRT and 187 received CCRT-AC. Median follow-up was 37 months. Significantly more patients with advanced clinical stage (stage IVA-IVB) received NAC-CCRT (86% in NAC-CCRT vs. 29% in CCRT-AC; p < 0.001). Compared to CCRT-AC in crude analysis, 3-year and 5-year OS of NAC-CCRT were 72% vs. 86% and 62% vs. 75% respectively (p = 0.059). Interestingly, the 3-year and 5-year post-estimation adjusted OS was 84% and 74% for NAC-CCRT and 81% and 70% for CCRT-AC, respectively (HR: 0.83, 95% confidence interval (CI): 0.45-1.56; p = 0.571). Also, adjusted analysis of distant-metastasis survival, NAC-CCRT showed HR was 0.79 (95% CI:0.37-1.72, p = 0.557). Conversely, adjusted analysis of locoregional relapse (LLR)-free survival revealed NAC-CCRT to have a significantly higher risk of LRR (HR: 2.18, 95% CI: 0.98-4.87; p = 0.057). Conclusions: The results suggested that prognosis in the NAC-CCRT treated patients was not superior to that of the CCRT-AC treated individuals. In patients that receive neoadjuvant chemotherapy, locoregional relapse should be of concern. High-risk distant metastasis patients (N3 stage) that could achieve survival advantage from NAC-CCRT is an interesting and important topic for further study.