Table 1 Patient and treatment characteristics

Age

median 61.6 years (range 36.9–91.4)

Gender

72% male (n = 134)

28% female (n = 53)

Histology

100% squamous cell carcinoma

Oropharyngeal subsite

52% tonsil (n = 97)

40% base of tongue (n = 75)

5% vallecula (n = 9)

2% soft palate (n = 4)

1% posterior wall (n = 2)

T stage (UICC 7th edition)

12% T1 (n = 22)

31% T2 (n = 59)

19% T3 (n = 36)

33% T4 (n = 61)

5% not available/recurrent disease (n = 9)

N stage (UICC 7th edition)

16% N0 (n = 30)

12% N1 (n = 22)

4% N2a (n = 7)

32% N2b (n = 60)

29% N2c (n = 55)

4% N3 (n = 7)

3% not available/recurrent disease (n = 6)

UICC Stage (7th edition)

8% Stage II (n = 15)

19% Stage III (n = 35)

67% Stage IVA (n = 122)

4% Stage IVB (n = 7)

2% Recurrent disease (n = 3)

ECOG performance score

80% ECOG 0 (n = 149)

15% ECOG 1 (n = 28)

5% ECOG 2 (n = 9)

Tumor volume (combined nodal and primary volume); n = events (any recurrence)

median 40 cm³ (range 3–216 cm³); overall 52 events

subgroup 1–15 cm³: 14% (n = 26); 3 events

subgroup 15–70 cm³: 60% (n = 112); 28 events

subgroup 70–130 cm³: 23% (n = 43); 17 events

subgroup >130 cm³: 3% (n = 6); 4 events

Smoking status

active = 62% (n = 116)

stopped =25% (n = 46)

never smoked = 13% (n = 25)

NLR

median 3.33 (range 0.91–33.71)

IMRT dose prescription

median 69.6 Gy (66–72 Gy)

single dose 2–2.11 Gy

Concomitant systemic therapy

42% cisplatin weekly (n = 78)

47% reduced number of cisplatin cycles (n = 87)

7% cetuximab (n = 14)

4% no systemic therapy (n = 7)

Induction chemotherapy

8% of patients (n = 15)

Follow-up

median 61.2 months (range 1.7–169)