title: Magnetic Resonance Imaging-Detected Tumor Residue after Intensity-Modulated Radiation Therapy and its Association with Post-Radiation Plasma Epstein-Barr Virus Deoxyribonucleic Acid in Nasopharyngeal Carcinoma.
abstract: Purpose: To evaluate the prognostic value of magnetic resonance imaging (MRI)-detected tumor residue after intensity-modulated radiation therapy (IMRT) and its association with post-treatment plasma Epstein-Barr virus deoxyribonucleic acid (EBV DNA) in nasopharyngeal carcinoma (NPC).Methods and materials: A prospective database of patients with histologically-proven NPC was used to retrospectively analyze 664 cases. Pre- and post-treatment MRI scans were independently reviewed by two senior radiologists who were blinded to clinical findings. Factors significantly associated with MRI-detected tumor residue were identified and included in the following multivariate logistic regression model. Residual risk model were established. Receiver operating characteristic (ROC) identify the optimal cut-off risk score for tumor residue.Results: MRI-detected residual tumor at three months after IMRT was associated with poor prognosis. The 5-year survival rates for the non-residual and residual groups were: OS (93.8% vs. 76.6%,P<0.001), PFS (84.7% vs. 67.9%,P=0.006), LRFS (93.4% vs. 80.4%,P=0.002), and DMFS (90.3% vs. 87.9%,P=0.305), respectively. Three-month post-treatment EBV DNA was significantly associated with tumor residue (P<0.001). A residual risk score model was established, consisting of T and N categories and post-treatment EBV DNA. ROC identified 22.74 as the optimal cut-off risk score for tumor residue. High-risk score was independently associated with poor treatment outcomes.Conclusions: MRI-detected tumor residue was an independent adverse prognostic factor in NPC; and significantly associated with three-month post-treatment EBV DNA. As limited resources in some endemic areas prevent patients from undergoing routine post-treatment imaging, our study identifies a selection risk-model, providing a cost-effective reference for the selection of follow-up strategies and clinical decision-making.
authors.affiliation: Department of Radiation Oncology, Sun Yat-sen University Cancer Center.
authors.forename: Jia-Wei
authors.initials: JW
authors.lastname: Lv
authors.affiliation: Department of Radiation Oncology, Sun Yat-sen University Cancer Center.
authors.forename: Guan-Qun
authors.initials: GQ
authors.lastname: Zhou
authors.affiliation: Department of Oncology, First People's Hospital of Zhaoqing, Guangdong, People's Republic of China.
authors.forename: Jia-Xiang
authors.initials: JX
authors.lastname: Li
authors.affiliation: Department of Radiation Oncology, Sun Yat-sen University Cancer Center.
authors.forename: Ling-Long
authors.initials: LL
authors.lastname: Tang
authors.affiliation: Department of Radiation Oncology, Sun Yat-sen University Cancer Center; Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, United States.
authors.forename: Yan-Ping
authors.initials: YP
authors.lastname: Mao
authors.affiliation: Department of Medical Statistics and Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou, People's Republic of China.
authors.forename: Ai-Hua
authors.initials: AH
authors.lastname: Lin
authors.affiliation: Department of Radiation Oncology, Sun Yat-sen University Cancer Center.
authors.forename: Jun
authors.initials: J
authors.lastname: Ma
authors.affiliation: Department of Radiation Oncology, Sun Yat-sen University Cancer Center.
authors.forename: Ying
authors.initials: Y
authors.lastname: Sun
keywords: Intensity-modulated radiation therapy; Magnetic resonance imaging; Nasopharyngeal carcinoma; Plasma EBV DNA; Tumor residue