Table 1 Patients and their clinico-pathological characteristics

All patients

45

100 %

Time between primary surgery and CTC sampling (DFI)

  ≤ 5 years

16

36 %

  > 5 years

21

47 %

 Primary not removed

8

18 %

Age at CTC sampling

  ≤ 50 years

4

9 %

  > 50 years

41

91 %

Menopausal status

 Premenopausal

2

4 %

 Postmenopausal

43

96 %

Histologic grade (Bloom-Richardson)

 I, well differentiated

5

11 %

 II, moderately differentiated

23

51 %

 III, poorly differentiated

4

9 %

 Unknown

13

29 %

Pathological tumor size

 pT1, ≤2 cm

20

44 %

 pT2-4, >2 cm

22

49 %

 Unknown

3

7 %

Lymph nodes involved

 No

14

31 %

 Yes

27

60 %

 Unknown

4

9 %

ERa status^a

 Negative

1

2 %

 Positive

44

98 %

PgR status^a

 Negative

5

11 %

 Positive

36

80 %

 Unknown

4

9 %

HER2/neu status^a

 Negative

37

82 %

 Positive

3

7 %

 Unknown

5

11 %

Histological type

 Lobular

13

29 %

 Ductal

28

62 %

 Ductolobular

3

7 %

 Ductal, signet-cell

1

2 %

Adjuvant chemotherapy

 No

31

69 %

 Yes

14

31 %

Adjuvant hormonal therapy

 No

24

53 %

 Yes

21

47 %

Any adjuvant therapy

 No

22

49 %

 Yes

23

51 %

Site of metastasis

 Visceral

5

11 %

 Non-visceral

26

58 %

 Both

14

31 %

1st line treatment

 Anastrozol

15

33 %

 Letrozol

16

36 %

 Exemestane

14

31 %

Median progression-free survival (PFS in days; range)^b

358 (14–1255)

Median baseline CTC count (range in 7.5 mL blood)

8 (0–32,492)