Post-radiation Plasma Epstein-Barr Virus DNA and Local Clinical Remission After Radical Intensity-modulated Radiation Therapy for Nasopharyngeal Carcinoma.
OBJECTIVE
We studied if post-radiation plasma Epstein-Barr virus (EBV) DNA predicted local clinical remission after radical intensity-modulated radiation therapy (IMRT) for nasopharyngeal carcinoma.


METHODS
Patients with non-metastatic nasopharyngeal carcinoma with baseline and serial plasma EBV DNA were treated with radical IMRT ± adjunct chemotherapy. Eight weeks after IMRT, they had plasma EBV DNA and routine six-site random nasopharyngeal biopsies on the same day. A repeat biopsy was carried out every 2 weeks if residual tumours were noted in previous biopsies until 12 weeks after IMRT when local persistence was defined. Correlation of undetectable plasma EBV DNA with local clinical remission was carried out.


RESULTS
Two hundred and sixty patients with serial plasma EBV DNA completed IMRT, after a median follow-up of 3.1 years. Only one (0.4%) suffered from local persistence. Area under the curve values of receiver operating characteristics of undetectable plasma EBV DNA for negative biopsy at 8 weeks and local persistence were 0.642 and 0.439, respectively. They increased to 0.856 (P = 0.007) and 0.952 (P = 0.119), respectively, when combined with age <65 years and T1/T2 stage.


CONCLUSIONS
Post-treatment plasma EBV DNA was not useful to predict local clinical remission in this study, probably because of excellent local control after IMRT. However, it may serve as a reference for high-risk patients treated with older radiation techniques.
Department of Clinical Oncology, Queen Mary Hospital, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China. Electronic address: vhflee@hku.hk.
V H F
VH
Lee
Department of Clinical Oncology, Queen Mary Hospital, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
D L W
DL
Kwong
Department of Clinical Oncology, Queen Mary Hospital, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
T W
TW
Leung
Department of Systems Engineering and Engineering Management, The City University of Hong Kong, Hong Kong, China.
C W
CW
Choi
Department of Clinical Oncology, Queen Mary Hospital, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
K O
KO
Lam
Department of Clinical Oncology, Queen Mary Hospital, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
C K
CK
Sze
Department of Clinical Oncology, Queen Mary Hospital, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
P
P
Ho
Department of Clinical Oncology, Queen Mary Hospital, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
W L
WL
Chan
Department of Clinical Oncology, Queen Mary Hospital, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
L S
LS
Wong
Department of Clinical Oncology, Queen Mary Hospital, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
D
D
Leung
D000328:Adult; D000368:Aged; D019540:Area Under Curve; D002277:Carcinoma; D017024:Chemotherapy, Adjuvant; D003131:Combined Modality Therapy; D004279:DNA, Viral / Q000097:blood*; D020031:Epstein-Barr Virus Infections / Q000097:blood / Q000150:complications*; D005260:Female; D004854:Herpesvirus 4, Human / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000097:blood / Q000532:radiotherapy / Q000821:virology*; D011379:Prognosis; D012372:ROC Curve; D050397:Radiotherapy, Intensity-Modulated
D004279:DNA, Viral
Intensity-modulated radiation therapy; local clinical remission; nasopharyngeal carcinoma; post-treatment plasma EBV DNA