Table 5.

Factors associated with disease-free interval (DFI) in canine invasive mammary carcinomas (n = 150)

Criteria	DFI: Univariate analysis			DFI: Multivariate analysis
	(log-rank test) N = 150			(Cox regression model) N = 150
	HR	95 % CI	p-value	HR	95 % CI	p-value
Body size			0.005			0.07
> 10 kgs	1.00	-		1.00
≤ 10 kgs	1.99	1.23–3.21		1.66	0.95–2.90
Age			0.007			0.02
<11 yrs	1.00	-		1.00	-
≥11 yrs	1.88	1.19–2.98		1.91	1.13–3.24
Multifocality			0.01			0.76
Unifocal	1.00	-		1.00	-
Multicentric	2.56	1.22–5.38		0.86	0.32–2.29
Histological grade			0.06			0.46
Grade I	1.00	-	-	1.00	-
Grade II	1.90	0.89–4.04	0.10	1.76	0.67–4.62	0.25
Grade III	2.43	1.17–5.06	0.02	1.83	0.69–4.86	0.22
Lymphovascular invasion			<0.001			0.04
No LVI	1.00	-		1.00	-
LVI	2.86	1.81–4.51		1.91	1.02–3.58
Surgical margins			0.005			0.15
Complete excision	1.00	-		1.00	-
Incomplete excision	1.94	1.22–3.07		1.57	0.85–2.88
Muscle infiltration			0.005			0.99
No	1.00	-		1.00	-
Yes	2.00	1.23–3.28		1.00	0.54–1.86
Peritumoral Inflammation			0.04			0.07
No	1.00	-		1.00	-
Yes	1.57	1.00–2.47		1.69	0.95–2.99
Central necrosis			0.03			0.04
No	1.00	-		1.00	-
Yes	0.56	0.34–0.93		0.52	0.28–0.97
Immunophenotype			0.02			0.18
Luminal	1.00	-		1.00	-
Triple negative	1.80	1.08–3.00		1.54	0.82–2.86
CK5/6			0.01			0.09
< 10 %	1.00	-		1.00	-
≥ 10 %	0.55	0.35–0.87		0.61	0.34–1.08
IGF1R			0.04			0.23
weak (0–1+)	1.00	-	-	1.00	-	-
moderate (2+)	1.22	0.68–2.19	0.51	1.15	0.58–2.28	0.70
strong (3+)	2.09	1.14–3.83	0.02	1.74	0.86–3.55	0.13

Univariate (log rank test) and multivariate survival analyses (Cox proportional hazard regression)

HR Hazard Ratio, 95 % CI 95 % Confidence Interval, CK5/6 Cytokeratin 5/6, IGF1R Insulin-like Growth Factor type 1 Receptor, LVI Lymphovascular Invasion