Table 1.

Clinical characteristics of study participants

Characteristic	No. patients		Percentage
Total	259		100
Sex
Male	194		74.9
Female	65		25.1
Median age (range); years	49 (19–74)
T category
T 1–2	34		13.1
T 3–4	225		86.9
N category
N 0–1	89		34.4
N 2–3	170		65.6
Stage
III	129		49.8
IVA	130		50.2
Plasma EBV-DNA (copies/mL)
≤ 500	173		66.8
> 500	86		33.2
95% of target volume received dose greater than (D95, Gy)
Average dose of nasopharynx (PTVnx + rn) (range)	70.2 (66.1–74.3)
Average dose of neck node (PTVnd) (range)	69.4 (60.7–75.9)
Sites of residual
Primary focus	121	46.7
Retropharyngeal lymph nodes	54	20.8
Cervical lymph nodes	152	58.7
Median time to boost after RT (range); days	36 (1–74)
Average boost dose for primary focus (range); Gy	8.1 (4–12.5)
Average boost dose for retropharyngeal lymph nodes (range); Gy	8.3 (5–12.5)
Average boost dose for cervical lymph nodes (range); Gy	8.6 (4–18)

EBV-DNA Epstein-Barr virus-deoxyribonucleic acid, PTVnx + rn planning gross target volume of the nasopharyngeal and retropharyngeal lymph node, PTVnd planning gross target volume of the cervical lymph nodes, RT radiotherapy