Table 3. Associations between HPV status and risk of recurrence, event and/or death.

Treatment group
	All (n=195)		Surgery alone (n=14)		Surgery with adjuvant radiotherapy (n=110)		Definitive radiotherapy alone (n=24)		Definitive radiotherapy and chemotherapy (n=47)
	HR (95% CI)	P-value	HR (95% CI)	P-value	HR (95% CI)	P-value	HR (95% CI)	P-value	HR (95% CI)	P-value
Loco-regional recurrence
Univariate
HPV
Negative	1.0		1.0		1.0		1.0		1.0
Positive	0.34 (0.17, 0.61)	0.0002	0.71 (0.04, 5.57)	0.8	0.38 (0.14, 0.91)	0.03	0.18 (0.03, 0.75)	0.02	0.36 (0.10, 1.03)	0.06
Adjusted
HPV
Negative	1.0				1.0		1.0		1.0
Positive	0.27 (0.13, 0.52)a	<0.0001	Not estimatedb		0.30 (0.10, 0.82)c	0.02	0.12 (0.01, 0.61)d	0.009	0.25 (0.06, 0.79)c	0.02
Event-free survival
Univariate
HPV
Negative	1.0		1.0		1.0		1.0		1.0
Positive	0.31 (0.19, 0.49)	<0.0001	0.50 (0.07, 2.10)	0.4	0.28 (0.13, 0.53)	<0.0001	0.19 (0.04, 0.60)	0.004	0.46 (0.19, 1.03)	0.06
Adjusted
HPV
Negative	1.0				1.0		1.0		1.0
Positive	0.23 (0.14, 0.39)a	<0.0001	Not estimatedb		0.19 (0.08, 0.40)c	<0.0001	0.14 (0.02, 0.54)d	0.003	0.36 (0.14, 0.85)c	0.02
Overall survival
Univariate
HPV
Negative	1.0		1.0		1.0		1.0		1.0
Positive	0.29 (0.17, 0.48)	<0.0001	0.98 (0.14, 4.57)	1.0	0.18 (0.07, 0.40)	<0.0001	0.24 (0.05, 0.82)	0.02	0.43 (0.17, 0.99)	0.05
Adjusted
HPV
Negative	1.0				1.0		1.0		1.0
Positive	0.24 (0.13, 0.42)a	<0.0001	Not estimatedb		0.11 (0.04, 0.28)c	<0.0001	0.11 (0.01, 0.52)d	0.004	0.37 (0.13, 0.90)c	0.03

Abbreviations: HPV=human papillomavirus; HR=hazard ratio; CI=confidence interval; RT=radiation therapy; CT=chemotherapy.

^aAdjusted for age, gender, tumour grade, tumour stage, primary site and treatment.

^bMultivariable analyses not carried out owing to small numbers.

^cAdjusted for age, gender, tumour grade, tumour stage and primary site.

^dAdjusted for age, tumour grade and tumour stage; gender and primary site not adjusted owing to categories with low numbers of events.