Table 1 Patient characteristics
|  | Total | c-MET+ CTC | EpCAM+ CTC | cfDNA concentration | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
Low (< 3) | High (≥ 3) | P value | Low (< 4) | High (≥ 4) | P value | Low (< 1490) | High (≥ 1490) | P value | ||
Age at diagnosis, n(%) | ||||||||||
Median (range) | 45 (29–65) | 46 (29–65) | 43 (32–59) |  | 46 (29–65) | 43 (33–63) |  | 45 (29–63) | 43 (31–65) |  |
50< | 60 | 48 (61.5) | 12 (80.0) | 0.28 | 48 (64.0) | 12 (66.7) | 1.00 | 33 (66.0) | 27 (62.8) | 0.92 |
50≥ | 33 | 30 (38.5) | 3 (20.0) |  | 27 (36.0) | 6 (33.3) |  | 17 (34.0) | 16 (37.2) |  |
Primary tumor subtype, n(%) | ||||||||||
HR+/HER2− | 63 | 57 (73.1) | 6 (40.0) | 0.02 | 51 (68.0) | 12 (66.7) | 1.00 | 34 (68.0) | 29 (67.4) | 1.00 |
HR+/HER2+ | 30 | 21 (26.9) | 9 (60.0) | Â | 24 (32.0) | 6 (33.3) | Â | 16 (32.0) | 14 (32.6) | Â |
Ki67 status (cut point = 20%), n(%) | ||||||||||
Low | 29 | 25 (50.0) | 4 (33.3) | 0.47 | 26 (46.4) | 3 (50.0) | 1.00 | 15 (53.6) | 14 (41.2) | 0.47 |
High | 33 | 25 (50.0) | 8 (66.7) | Â | 30 (53.6) | 3 (50.0) | Â | 13 (46.4) | 20 (58.8) | Â |
NA | 31 | 28 | 3 | Â | 19 | 12 | Â | 22 | 9 | Â |
Histologic grade, n(%) | ||||||||||
1 | 7 | 6 (8.3) | 1 (8.3) | 0.27 | 4 (5.9) | 3 (18.8) | 0.21 | 4 (9.3) | 3 (7.3) | 0.35 |
2 | 56 | 50 (69.4) | 6 (50.0) | Â | 47 (69.1) | 9 (56.3) | Â | 31 (72.1) | 25 (61.0) | Â |
3 | 21 | 16 (22.2) | 5 (41.7) | Â | 17 (25.0) | 4 (25.0) | Â | 8 (18.6) | 13 (31.7) | Â |
NA | 9 | 6 | 3 | Â | 7 | 2 | Â | 7 | 2 | Â |
Nuclear grade, n(%) | ||||||||||
1 | 4 | 4 (5.6) | 0 (0.0) | 0.35 | 3 (4.5) | 1 (5.9) | 1.00 | 2 (4.7) | 2 (4.9) | 0.09 |
2 | 58 | 51 (70.8) | 7 (58.3) | Â | 46 (68.7) | 12 (70.6) | Â | 34 (79.1) | 24 (58.5) | Â |
3 | 22 | 17 (23.6) | 5 (41.7) | Â | 18 (26.9) | 4 (23.5) | Â | 7 (16.3) | 15 (36.6) | Â |
NA | 9 | 6 | 3 | Â | 8 | 1 | Â | 7 | 2 | Â |
ECOG performance score, n(%) | ||||||||||
0 | 19 | 17 (22.1) | 2 (13.3) | 0.73 | 15 (20.3) | 4 (22.2) | 1.00 | 8 (16.3) | 11 (25.6) | 0.40 |
1 | 73 | 60 (77.9) | 13 (86.7) | Â | 59 (79.7) | 14 (77.8) | Â | 41 (83.7) | 32 (74.4) | Â |
NA | 1 | 22 | 0 | Â | 22 | 0 | Â | 1 | 0 | Â |
Metastatic sites, n(%) | ||||||||||
Visceral | 59 | 49 (62.8) | 10 (66.7) | 0.99 | 48 (64.0) | 11 (61.1) | 0.86 | 30 (60.0) | 29 (67.4) | 0.68 |
Bone only | 13 | 11 (14.1) | 2 (13.3) | Â | 11 (14.7) | 2 (11.1) | Â | 7 (14.0) | 6 (14.0) | Â |
Others | 21 | 18 (23.1) | 3 (20.0) | Â | 16 (21.3) | 5 (27.8) | Â | 13 (26.0) | 8 (18.6) | Â |
Line of palliative therapy, n(%) | ||||||||||
1 | 37 | 30 (38.5) | 7 (46.7) | 0.88 | 27(36.0) | 10 (55.6) | 0.25 | 30 (60.0) | 7 (16.3) |  < 0.001 |
2 | 22 | 19 (24.4) | 3 (20.0) | Â | 20 (26.7) | 2 (11.1) | Â | 7 (14.0) | 15 (34.9) | Â |
≥ 3 | 34 | 29 (37.2) | 5 (33.3) |  | 28 (37.3) | 6 (33.3) |  | 13 (26.0) | 21 (48.8) |  |
Treatment, n(%) | ||||||||||
Cytotoxic chemotherapy | 35 | 32 (41.0) | 3 (20.0) | 0.32 | 28 (35.3) | 7 (38.9) | 0.61 | 17 (34.0) | 18 (41.9) | 0.33 |
Targeted agents | 18 | 14 (17.9) | 4 (26.7) | Â | 16 (21.3) | 2 (11.1) | Â | 7 (14.0) | 11 (25.6) | Â |
Endocrine therapy only | 5 | 5 (6.4) | 0 (0.0) | Â | 5 (6.7) | 0 (0.0) | Â | 3 (6.0) | 2 (4.7) | Â |
Endocrine therapy + CDK4/6i | 31 | 24 (30.8) | 7 (46.7) |  | 23 (30.7) | 8 (44.4) |  | 21 (42.0) | 10 (23.3) |  |
Endocrine therapy + Targeted agents | 4 | 3 (3.8) | 1 (6.7) |  | 3 (4.0) | 1 (5.6) |  | 2 (4.0) | 2 (4.7) |  |
Previous endocrine therapy, n(%) | ||||||||||
Yes | 76 | 65 (83.3) | 11 (73.3) | 0.46 | 61 (82.4) | 15 (83.3) | 1.00 | 43 (87.8) | 33 (76.7) | 0.27 |
No | 17 | 13 (16.7) | 4 (26.7) | Â | 13 (17.6) | 3 (16.7) | Â | 6 (12.2) | 10 (23.3) | Â |
Previous chemotherapy in any setting, n(%) | ||||||||||
Yes | 77 | 63 (80.8) | 14 (93.3) | 0.45 | 61 (81.3) | 16 (88.9) | 0.73 | 39 (78.0) | 38 (88.4) | 0.30 |
No | 16 | 15 (19.2) | 1 (6.7) | Â | 14 (18.7) | 2 (11.1) | Â | 11 (22.0) | 5 (11.6) | Â |