Table 3. Independent factors from the multivariate Cox regression analyses.

Multivariate Cox regression	HR (95% CI)	P
Overall survival
DTBC (per tertile increase)	1.6 (1.1-2.2)	0.01
Lymph node metastasesa	1.7 (1.3-2.2)	<0.001
Age at diagnosis (per 1 year increment)	1.0 (1.0-1.1)	0.007
Progression-free survival
DTBC (per tertile increase)	2.3 (1.5-3.8)	<0.001
Lymph node metastasesb	1.5 (1.1-2.2)	0.01

a: The hazard ratio for lymph node metastases represents an increase in size from no metastases to macrometastases as seen in Table 2.

Abbreviations: HR, hazard ratio, DTBC, Digital tumor bud count.