Table 3.

Clustered survival analysis to assess factors associated with time to local recurrence of tumour^*

Factor	HR (95% CI)
Intervention arm (v. control arm)	0.96 (0.61–1.52)
Sex, male (v. female)	1.01 (0.60–1.70)
Age, per 10-year increase	1.01 (0.75–1.37)
Comorbidities (v. none)
1	0.84 (0.48–1.45)
≥ 2	0.91 (0.39–2.12)
Tumour size, per 1-cm increase	1.10 (1.00–1.20)
TNM stage (v. stage 1)
2	1.30 (0.54–3.12)
3	1.36 (0.57–3.25)
4	1.47 (0.49–4.36)
Histologic grade (v. poorly differentiated)
Moderately differentiated	1.10 (0.47–2.58)
Well differentiated	0.84 (0.30–2.37)
Vascular, lymphatic or neural invasion (v. none)	0.86 (0.48–1.57)
Positive circumferential radial margin† (v. negative margin)	2.02 (0.70–5.83)
Any use of radiation (v. no use)	1.38 (0.82–2.33)
Low anterior resection (v. permanent colostomy)	0.82 (0.56–1.19)

Note: CI = confidence interval, HR = hazard ratio.

^*Model considered clustering of data at hospital level.

^†Positive circumferential radial margin = distance ≤ 1mm.