Abstract
AIM: The present study aimed to evaluate the combined value of locoregional extension patterns (LEPs) and circulating cell-free Epstein-Barr virus (cf EBV) DNA for risk stratification of locoregionally advanced nasopharyngeal carcinoma (LA-NPC) to better guide therapeutic strategies. METHODS: A total of 7227 cases of LA-NPC were reviewed retrospectively and classified into six groups according to their LEP (ascending, descending, or mixed type) and pre-treatment cf EBV-DNA load (⩾ versus <4000 copy/ml). Using a supervised statistical clustering approach, patients in the six groups were clustered into low, intermediate, and high-risk clusters. Progression-free survival (PFS), overall survival (OS), distant metastasis-free survival (DMFS), and locoregional relapse-free survival (LRRFS) were calculated using the Kaplan-Meier method and differences were compared using the log-rank test. RESULTS: Survival curves for the low, intermediate, and high-risk clusters were significantly different for all endpoints. The 5-year survival rate for the low, intermediate, and high-risk clusters, respectively, were: PFS (83.5%, 73.2%, 62.6%, p < 0.001), OS (91.0%, 82.7%, 73.2%, p < 0.001), DMFS (92.3%, 83.0%, 73.4%, p < 0.001), and LRRFS (91.0%, 88.0%, 83.3%, p < 0.001). The risk clusters acted as independent prognostic factors for all endpoints. Among the patients in the high-risk cluster, neoadjuvant chemotherapy combined with concurrent chemoradiotherapy (CCRT) significantly improved the patients 5-year PFS (66.4% versus 57.9%, p = 0.014), OS (77.6% versus 68.6%; p < 0.002), and DMFS (76.6% versus 70.6%; p = 0.028) compared with those treated with CCRT. CONCLUSION: Our results could facilitate the development of risk-stratification and risk-adapted therapeutic strategies for patients with LA-NPC.