Table 5a. Treatment effect for unplanned subgroups that may have influenced outcome.

Treatment effect within oropharynx and non-oropharynx subgroups ^*

Endpoint	All sites	Oropharynx	Non-Oropharynx
All eligible patients
LRC	0.73 (0.49–1.07)	0.63 (0.33–1.19)	0.84 (0.51–1.37)
DFS	0.88 (0.71–1.09)	0.95 (0.66–1.38)	0.93 (0.71–1.23)
OS	0.89 (0.70–1.12)	0.95 (0.64–1.42)	0.95 (0.71–1.26)
Limited to eligible patients with positive margin and/or ECE
LRC	0.56 (0.34–0.92)	0.49 (0.21–1.11)	0.65 (0.34–1.22)
DFS	0.76 (0.57–1.00)	0.77 (0.49–1.23)	0.83 (0.58–1.19)
OS	0.76 (0.57–1.03)	0.82 (0.50–1.34)	0.84 (0.58–1.21)

^*Univariate hazard ratio and 95% confidence interval

LRC = L-R control