Longitudinal enumeration and cluster evaluation of circulating tumor cells improve prognostication for patients with newly diagnosed metastatic breast cancer in a prospective observational trial

Table 2 Cox regression hazard ratios for CTC count ≥ 5 versus < 5, and presence versus absence of CTC clusters

	PFS	P value	OS	P value
	HR (95% CI)	P value	HR (95% CI)	P value
Baseline
Unadjusted
CTC ≥ 5	1.68 (1.17–2.42)	0.005	2.52 (1.58–4.01)	< 0.001
Clusters present	1.54 (1.00–2.40)	0.05	2.23 (1.35–3.69)	0.002
Adjusted^a
CTC ≥ 5	2.30 (1.43–3.71)	0.001	3.92 (2.09–7.36)	< 0.001
Clusters present	2.64 (1.46–4.78)	0.001	4.07 (1.99–8.31)	< 0.001
One month^b
Unadjusted
CTC ≥ 5	2.17 (1.43–3.30)	< 0.001	4.38 (2.63–7.30)	< 0.001
Clusters present	3.23 (1.70–-6.14)	< 0.001	4.52 (2.24–9.15)	< 0.001
Adjusted^c
CTC ≥ 5	2.30 (1.23–4.32)	0.009	4.39 (2.04–9.43)	< 0.001
Clusters present	3.37 (1.51–7.55)	0.003	5.67 (2.30–13.95)	< 0.001
Three months^b
Unadjusted
CTC ≥ 5	2.24 (1.24–4.03)	0.07	3.28 (1.76–6.12)	< 0.001
Clusters present	3.16 (1.60–6.22)	0.001	3.35 (1.68–6.68)	0.001
Adjusted^c
CTC ≥ 5	2.95 (1.44–6.06)	0.003	5.93 (2.62–13.42)	< 0.001
Clusters present	3.04 (1.35–6.84)	0.007	3.55 (1.44–8.77)	0.006
Six months^b
Unadjusted
CTC ≥ 5	4.33 (2.10–8.93)	< 0.001	7.74 (3.52–16.99)	< 0.001
Clusters present	6.48 (2.26–18.56)	0.001	9.92 (3.30–29.78)	< 0.001
Adjusted^c
CTC ≥ 5	6.43 (2.30–17.94)	< 0.001	15.72 (3.79–65.17)	< 0.001
Clusters present	7.17 (2.03–25.36)	0.002	21.65 (5.06–92.63)	< 0.001

Abbreviations: PFS progression-free survival, OS overall survival, HR hazard ratio, CTC circulating tumor cell
^aAdjusted for the variables included in the clinicopathological model (Additional file 3)
^bAssessed by landmark analysis
^cAdjusted for the variables included in the clinicopathological model (Additional file 3) and for baseline CTC count (< 5 vs ≥ 5)

ISSN: 1465-542X