Table 1 Clinical characteristics of study participants

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)