Table 2 Tumor characteristics for the three patient groups

Tumor Location

 Tonsil

23 (54.8%)

8 (34.8%)

18 (56.3%)

0.23

 Base of Tongue

18 (42.9%)

12 (52.2%)

11 (34.4%)

 Other

1 (2.4%)

3 (13.0%)

3 (9.4%)

Tumor Laterality

 Right

21 (50.0%)

9 (39.1%)

17 (53.1%)

0.67

 Left

18 (42.9%)

11 (47.8%)

14 (43.8%)

 Bilateral

3 (7.1%)

3 (13.0%)

1 (3.1%)

Perineural Invasion

 Yes

3 (8.8%)

7 (31.8%)

4 (14.3%)

0.089

 No

31 (91.2%)

15 (68.2%)

24 (85.7%)

Vascular Invasion

 Yes

10 (27.0%)

8 (25%)

3 (11.1%)

0.095

 No

27 (73.0%)

14 (75%)

24 (88.9%)

Lymphatic Invasion

 Yes

16 (43.2%)

15 (68.2%)

10 (34.5%)

0.054

 No

21 (56.8%)

7 (31.8%)

19 (65.5%)

Extracapsular Extension

 Positive

35 (87.5%)

21 (91.3%)

26 (81.3%)

0.56

 Negative

5 (12.5%)

2 (8.7%)

6 (18.7%)

Soft Tissue Metastases

 Yes

20 (64.5%)

14 (66.7%)

17 (65.4%)

1.00

 No

11 (35.5%)

7 (33.3%)

9 (34.6%)

Tumor Size (cm)

 Median (range)

2.0 (0.2 – 6.0)

4.0 (1.2 – 12.0)

2.25 (0.5 – 6.6)

0.0014

Tumor Depth (cm)

 Median (range)

0.75 (0.05 – 5.0)

1.2 (0.45 – 4.5)

0.65 (0.12 – 1.9)

0.014

Pathologic T stage

 T1

23 (54.8%)

2 (8.7%)

13 (40.6%)

<0.0001

 T2

14 (33.3%)

5 (21.7%)

17 (53.1%)

 T3

3 (7.1%)

6 (26.1%)

2 (6.3%)

 T4a

2 (4.8%)

10 (43.5%)

0 (0%)

Largest Lymph Node (cm)

 Median (range)

3.0 (1.3 – 6.0)

3.7 (0.7 – 6.0)

3.3 (0.6 – 7.5)

0.67

Total Number of Metastatic Lymph Nodes

 Median (range)

2 (1 – 15)

4 (1 – 25)

2 (1 – 40)

0.19

Pathologic N stage

 N1

9 (21.4%)

2 (8.7%)

7 (21.9%)

0.072

 N2a

9 (21.4%)

4 (17.4%)

2 (6.3%)

 N2b

20 (47.6%)

11 (47.8%)

16 (50.0%)

 N2c

4 (9.5%)

6 (26.1%)

3 (9.4%)

 N3

0 (0%)

0 (0%)

4 (12.5%)

Pathologic stage

 III

9 (21.4%)

1 (4.3%)

7 (21.9%)

0.016

 IVA

33 (79.6%)

22 (95.7%)

21 (65.6%)

 IVB

0 (0%)

0 (0%)

4 (12.5%)