Prognostic value of plasma Epstein–Barr virus DNA level during posttreatment follow-up in the patients with nasopharyngeal carcinoma having undergone intensity-modulated radiotherapy

Table 3 Plasma EBV DNA levels in the 93 patients with detectable EBV DNA during posttreatment follow-up

Emergence of plasma EBV DNA during posttreatment follow-up	Disease free	Tumor recurrence	P ^d
No. of patients	40	53	NA
Before clinical detection^a [n (%)]	NA	29 (54.7)	NA
Transiently detectable^b [n (%)]	39 (97.5)	5 (9.4)	< 0.001
Plasma EBV DNA level^c [copies/mL; median (range)]	805 (30–8840)	3940 (40–2,420,000)	NA
EBV DNA^c > 500 copies/mL [n (%)]	24 (60.0)	42 (79.2)	0.043
EBV DNA^c > 1000 copies/mL [n (%)]	16 (40.0)	37 (69.8)	0.004

NA not applicable
^a Emergence of plasma EBV DNA during posttreatment follow-up before clinical detection of recurrence
^bPlasma EBV DNA was transiently detected followed by a rapid regression to be undetectable
^cThe emergence level of EBV DNA during posttreatment follow-up period
^d P values were calculated using the χ² test

ISSN: 2523-3548