Combination of MRI-based temporal tumor response and Epstein-Barr DNA level changes after radiotherapy leads to improved prognostic stratification of patients with nasopharyngeal carcinoma treated with concurrent chemoradiotherapy

Objectives To investigated the prognostic value of temporal tumor response (TR) and plasma Epstein-Barr virus (EBV) DNA level changes at the end of radiotherapy (pRT0) and 3 months after radiotherapy (pRT3) in nasopharyngeal carcinoma (NPC) patients. Methods A total of 651 patients with biopsy-proven NPC, treated with concurrent chemo-radiotherapy, were retrospectively enrolled. TR and plasma EBV DNA levels were evaluated at pRT0 and pRT3. Progression-free survival (PFS) was the primary endpoint. Results Temporal change of tumor response (TRC) indicated that the refractory-disease group (where TR remained a non-complete response [non-CR] at pRT0 and pRT3) and slow-response group (where TR changed from non-CR to CR at pRT3) had a higher risk than the rapid-response group (where TR remained a CR at pRT0 and pRT3) in the 5-year locoregional relapse-free survival (LRRFS, P P