The time frame of Epstein-Barr virus latent membrane protein-1 gene to disappear in nasopharyngeal swabs after initiation of primary radiotherapy is an independently significant prognostic factor predicting local control for patients with nasopharyngeal carcinoma.
OBJECTIVE
The presence of Epstein-Barr virus latent membrane protein-1 (LMP-1) gene in nasopharyngeal swabs indicates the presence of nasopharyngeal carcinoma (NPC) mucosal tumor cells. This study was undertaken to investigate whether the time taken for LMP-1 to disappear after initiation of primary radiotherapy (RT) was inversely associated with NPC local control.


METHODS
During July 1999 and October 2002, there were 127 nondisseminated NPC patients receiving serial examinations of nasopharyngeal swabbing with detection of LMP-1 during the RT course. The time for LMP-1 regression was defined as the number of days after initiation of RT for LMP-1 results to turn negative. The primary outcome was local control, which was represented by freedom from local recurrence.


RESULTS
The time for LMP-1 regression showed a statistically significant influence on NPC local control both univariately (p < 0.0001) and multivariately (p = 0.004). In multivariate analysis, the administration of chemotherapy conferred a significantly more favorable local control (p = 0.03). Advanced T status (> or = T2b), overall treatment time of external photon radiotherapy longer than 55 days, and older age showed trends toward being poor prognosticators. The time for LMP-1 regression was very heterogeneous. According to the quartiles of the time for LMP-1 regression, we defined the pattern of LMP-1 regression as late regression if it required 40 days or more. Kaplan-Meier plots indicated that the patients with late regression had a significantly worse local control than those with intermediate or early regression (p = 0.0129).


CONCLUSIONS
Among the potential prognostic factors examined in this study, the time for LMP-1 regression was the most independently significant factor that was inversely associated with NPC local control.
Lin
Shinn-Yn
SY
Department of Radiation Oncology, Chang Gung Memorial Hospital, Linkou, Taiwan, ROC.
Chang
Kai-Ping
KP
Hsieh
Meng-Shu
MS
Ueng
Shir-Hwa
SH
Hao
Sheng-Po
SP
Tseng
Chen-Kan
CK
Pai
Ping-Ching
PC
Chang
Fu-Ti
FT
Tsai
Ming-Hsui
MH
Tsang
Ngan-Ming
NM
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000188:drug therapy / Q000235:genetics* / Q000532:radiotherapy*; D009363:Neoplasm Proteins / Q000235:genetics* / Q000378:metabolism; D013997:Time Factors; D014763:Viral Matrix Proteins / Q000235:genetics* / Q000378:metabolism
C037662:EBV-associated membrane antigen, Epstein-Barr virus; D009363:Neoplasm Proteins; D014763:Viral Matrix Proteins