Table 3 Patient-, tumor-and treatment-related factors compared to local and locoregional recurrences

Local recurrence

p-value

Hazard ratio

(95% confidence interval)

Locoregional recurrence

p-value

Hazard ratio

(95% confidence interval)

 Gender

0.389

0.050

  female vs. male

0.38 (0.04–3.69)

0.16 (0.02–1.31)

 Age at diagnosis

0.839

0.828

  ≥70y vs. <70y

1.27 (0.13–12.24)

0.79 (0.09–6.68)

Tumor-related

 Primary tumor site

0.368

0.664

  non-parotid vs. parotid

0.37 (0.04–3.54)

0.72 (0.16–3.23)

 Histologic Subtype

0.541

0.953

  non-adenoidcystic vs.

2.00

0.956

  adenoid cystic

(0.21–19.21)

(0.21–4.29)

 T classification

0.773

0.196

  T3/4 vs. T1/2

1.39 (0.15–13.43)

3.75 (0.44–31.85)

 Primary tumor size, cm

0.703

0.711

  >3 cm vs. ≤ 3 cm

0.63 (0.06–6.95)

1.35 (0.27–6.72)

 N classification

0.075

0.227

  N1/2 vs. N0

53.2 (0.02–180,704.08)

2.68 (0.51–14.09)

 Number of metastatic lymph nodes

0.285

0.224

  >1 vs. ≤ 1

3.42 (0.31–37.85)

2.68 (0.52–13.88)

 Histological tumor grade

0.747

0.537

  High vs. low/intermediate

1.20 (0.39–3.75)

1.30 (0.56–2.99)

 Extranodal extension

0.228

0.581

  yes vs. no

0.03 (0.00–656.48)

0.55 (0.06–4.78)

 Perineural Spread

0.222

0.403

  yes vs. no

0.27 (0.03–2.60)

0.41 (0.05–3.51)

Lymphovascular invasion

0.163

0.587

yes vs. no

4.72 (0.43–52.22)

1.64 (0.27–9.82)

 Vascular invasion

0.380

0.680

  yes vs. no

2.80 (0.25–31.05)

1.58 (0.18–14.23)

 Bone invasion

0.222

0.603

  yes vs. no

3.72 (0.39–36.03)

1.75 (0.21–14.60)

Treatment-related

 Resection margin

0.119

0.179

  R1/2 vs. R0

5.04 (0.52–48.53)

2.81 (0.62–12.72)

 Resection margin

0.002

0.031

  R2 vs R0/1

11.26 (1.58–80.45)

5.15 (0.98–26.93)

 Second primary tumor resection

0.293

0.543

  yes vs. no

0.034 (0.00–910.95)

0.52 (0.06–4.37)

 Neck Dissection

0.598

0.852

  yes vs. no

0.55 (0.06–5.28)

1.22 (0.15–10.18)

 Number of dissected nodes

0.675

0.708

  ≥10 vs. < 10

0.60 (0.05–6.64)

1.50 (0.18–12.88)

 Lymph node density (%)

0.110

0.246

  >4 vs. ≤4

56.27 (0.01–637,456.03)

2.71 (0.48–15.42)

 Radiation dose

0.333

0.698

  ≥64Gy vs. <64Gy

0.34 (0.04–3.31)

0.66 (0.08–5.50)

 Planning target Volume

0.318

0.108

  primary tumor region &

28.57 (0.00–1,127,372.02)

34.53 (0.03–47,010.85)

  regional lymph drainage vs.

  primary tumor region

 Radiation technique

0.099

0.226

  IMRT vs. 3D

0.02 (0.00–82.02)

0.290 (0.03–2.45)