Table 1 Clinicopathological characteristics of the patients

Age

 Median

62.5

66

64

n

%

n

%

n

%

Sex

 Male

20

62.5

6

50

26

59.1

 Female

12

37.5

6

50

18

40.9

Tumor site

 Oropharynx

19

59.4

5

41.7

24

54.5

 Oral cavity

6

18.8

1

8.3

7

15.9

 Larynx

3

9.4

5

41.7

8

18.2

 Hypopharynx

4

12.5

1

8.3

5

11.4

HPV status⁺

 Negative

18

56.3

1

8.3

19

43.2

 Positive

8

25.0

4

33.0

12

27.3

 n/a

6

18.8

7

58.3

13

29.5

Smoking

 Never

3

9.4

1

8.3

4

9.1

 Former

9

28.1

4

33.3

13

29.5

 Current

19

59.4

4

33.3

23

52.3

 n/a

1

3.1

3

25.0

4

9.1

Alcohol consumption

 Never

4

8.8

0

0

4

9.1

 Former

8

26.5

6

50.0

14

31.8

 Current

15

44.1

1

8.3

16

36.4

 n/a

5

20.6

5

41.7

10

22.7

Tumor size

 T1

2

6.3

4

33.3

6

13.6

 T2

14

43.8

4

33.3

18

40.9

 T3

9

28.1

1

8.3

10

22.7

 T4

7

21.9

3

25.0

10

22.7

Lymph node status

 N0

9

28.1

4

33.3

13

29.5

 N1

8

25.0

5

41.7

13

29.5

 N2

9

28.1

2

16.7

11

25.0

 N3

6

18.8

1

8.3

7

15.9

Metastases

 M0

32

100

12

100

44

100

UICC stages^*

 I

4

12.5

3

25.0

7

15.9

 II

4

12.5

2

16.7

6

13.6

 III

9

28.1

4

33.3

13

29.5

 IV

15

46.9

3

25.0

18

40.9

Therapy

 Surgery

4

12.5

3

25.0

7

15.9

 Surgery plus CRT

14

43.8

5

41.7

19

43.2

 Surgery plus RT

6

18.8

1

8.3

7

15.9

 Primary CRT

5

15.6

3

25.0

8

18.2

 Palliative RT

3

9.4

0

0

3

6.8

Time between end of therapy and sample collection

  < 6 months

3

25.0

  > 6 months

3

25.0

 > 2 years

6

50.0