TABLE 1.
Clinical characteristics of 33 metastatic breast cancer patients at pretreatment
| Description | Clinical and pathological features |
|---|---|
| Number of patients | 33 |
| Median age, y (range) | 54 (35–73) |
| Pathology (n = 33) | |
| Invasive ductal carcinoma | 32 (97) |
| Others | 1 (3) |
| Receptor status (n = 33) | |
| ER+PR+ HER2− | 30 (91) |
| ER+PR− HER2− | 3 (9) |
| Tumor response (n = 33) | |
| Complete response | 1 (4) |
| Partial response | 9 (27) |
| Stable disease | 15 (45) |
| Progressive disease | 8 (24) |
| Menopausal status (n = 33) | |
| Premenopausal | 12 (36) |
| Postmenopausal | 21 (64) |
| CDK4/6i (n = 33) | |
| Palbociclib + endocrine therapy | 30 (91) |
| Abemaciclib + endocrine therapy | 3 (9) |
| Visceral metastases (n = 33) | |
| Yes | 17 (52) |
| No | 16 (48) |
| RECIST criteria (n = 33) | |
| Measurable | 13 (39) |
| Nonmeasurable | 20 (61) |
| Prior lines of endocrine therapy (n = 33) a | |
| 0 line | 5 (15) |
| 1 line | 13 (39) |
| 2 lines | 5 (15) |
| 3+ lines | 10 (31) |
| Prior lines of metastatic therapy (n = 33) | |
| 0 line | 12 (36) |
| 1 line | 10 (30) |
| 2 lines | 4 (12) |
| 3+ lines | 7 (22) |
| ctDNA median follow‐up, mo (range) | |
| All patients (n = 33) | 12 (1–24) |
| Progressive disease (n = 20) | 6 (1–24) |
| Responders (n = 13) | 18 (6–24) |
Data are shown as n (%) unless otherwise noted.
Abbreviations: CDK4/6i, cyclin‐dependent kinase 4/6 inhibitor; ctDNA, circulating tumor DNA; ER, estrogen receptor; HER2, human epidermal growth factor receptor 2; PR, progesterone receptor.
a
Prior lines of endocrine therapy include adjuvant and metastatic regimens prior to CDK4/6i treatment.