Table 3. Patient characteristics according to margin methylation status.

	Margin hypermethylation
	+	−	P-valuea
Age, years
Mean±s.d.	61.6±11.1	58.3±9.7
Median (maximum, minimum)	64 (40, 77)	61 (32, 68)	0.72
Sex
Male	8 (72.7)	12 (92.3)
Female	3 (27.3)	1 (7.7)	0.3
Site, n (%)
Oral cavity	6 (54.5)	4 (30.8)
Oropharynx	5 (45.5)	4 (30.8)
Hypopharynx	0 (0)	4 (30.8)
Larynx	0 (0)	1 (7.7)	0.15
Tumour stage, n (%)
I–II	4 (36.4)	3 (23.1)
III–IV	7 (63.4)	10 (76.9)	0.67
Histopathological gravity signsb, n (%)
No	9 (81.8)	12 (92.3)
Yes	2 (18.2)	1 (7.7)	0.58
Adjuvant therapyc, n (%)
No	4 (36.4)	7 (53.8)
Yes	7 (63.4)	6 (46.2)	0.17
Disease-specific event, n (%)
No	5 (45.5)	13 (100)
Yes	6 (54.5)	0 (0)	0.01
Locoregional recurrence, n (%)
No	8 (72.7)	13 (100)
Yes	3 (27.3)	0 (0)	0.03d
Disease-specific death, n (%)
No	7 (63.4)	13 (100)
Yes	4 (36.4)	0 (0)	0.01d

^aFisher's exact test.

^bHistopathological gravity signs: perineural invasion, angiolymphatic invasion or both.

^cConcurrent chemoradiotherapy or radiotherapy alone.

^dLog-rank test.