Prognostication of Serial Post-Intensity-Modulated Radiation Therapy Undetectable Plasma EBV DNA for Nasopharyngeal Carcinoma

Oncotarget. 2017 Jan 17;8(3):5292-5308. doi: 10.18632/oncotarget.14137.

Abstract

Plasma Epstein-Barr virus (EBV) DNA titers have been used to monitor treatment response and provide prognostic information on survival for nasopharyngeal carcinoma (NPC). However, the long-term prognostic role of pretreatment and posttreatment titers after radical contemporaneous radiation therapy remains uncertain. We recruited 260 evaluable patients with non-metastatic NPC treated with radical intensity-modulated radiation therapy (IMRT) with or without adjunct chemotherapy. Plasma EBV DNA titers at baseline and then 8 weeks and 6 months after IMRT were measured. Cox regression models were employed to identify interaction between post-IMRT 8th week and 6th month undetectable titers and 3-year survival endpoints. Concordance indices (Ct) from time-dependent receiver-operating characteristics (TDROC) were compared between patients with post-IMRT undetectable and those with detectable titers. After a median follow-up duration of 3.4 years (range 1.4-4.6 years), patients with post-IMRT 8th week and 6th month undetectable plasma EBV DNA titers enjoyed longer 3-year survival endpoints than those who had detectable titers at the same time points. Post-IMRT 8th week, and more significantly, post-IMRT 6th month undetectable plasma EBV DNA were the only significant prognostic factors of 3-year survival endpoints. Ct values for all 3-year survival endpoints for both post-IMRT 8th week and 6th month undetectable plasma EBV DNA were significantly higher in those with stage IVA-IVB diseases compared to stage I-III counterparts. Early post-IMRT undetectable plasma EBV DNA titers were prognostic of 3-year survival endpoints in patients with non-metastatic NPC. Intensified treatment should be further explored for patients with persistently detectable titers after IMRT.

Keywords: intensity-modulated radiation therapy; nasopharyngeal carcinoma; non-metastatic; plasma EBV DNA; prognostic factors.

Publication types

  • Clinical Trial

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Carcinoma / blood
  • Carcinoma / radiotherapy*
  • Carcinoma / virology
  • DNA, Viral / blood
  • Disease-Free Survival
  • Epstein-Barr Virus Infections / blood
  • Epstein-Barr Virus Infections / radiotherapy*
  • Epstein-Barr Virus Infections / virology
  • Female
  • Herpesvirus 4, Human / genetics*
  • Humans
  • Male
  • Middle Aged
  • Nasopharyngeal Carcinoma
  • Nasopharyngeal Neoplasms / blood
  • Nasopharyngeal Neoplasms / radiotherapy*
  • Nasopharyngeal Neoplasms / virology
  • Prognosis
  • ROC Curve
  • Radiotherapy, Intensity-Modulated / methods*
  • Survival Analysis
  • Viral Load
  • Young Adult

Substances

  • DNA, Viral