Table 1.
Baseline characteristics of the study population (N = 95).
| Total cohort N = 95 | |
|---|---|
| Age at inclusion (years) | 65.4 (54.9–74.7) |
| Female gender | 91 (95.8%) |
| Histological type | |
| IDC/NST | 59 (62.1%) |
| ILC | 23 (24.2%) |
| Other or not reported | 13 (13.7%) |
| Molecular subtype | |
| HR+/HER2− | 95 (100.0%) |
| Bone metastases | 63 (66.3%) |
| Lung metastases | 23 (24.2%) |
| Liver metastases | 21 (22.1%) |
| Pleura metastases | 10 (10.5%) |
| Lymph node metastases | 30 (31.6%) |
| Number of metastatic sites | |
| 0–1 sitesa | 45 (47.4%) |
| ≥2 sites | 50 (52.6%) |
| Treatment line at inclusion | |
| ≤2 lines | 76 (80.0%) |
| >2 lines | 19 (20.0%) |
| PIK3CA mutation detected in plasma (N = 93)b | 44 (47.3%) |
| PIK3CA mutation detected in tissue (N = 74)c | 36 (48.6%) |
| Source of tissue (N = 74) | |
| Metastasis | 45 (60.8%) |
| Primary tumour | 29 (39.1%) |
| Interval between tissue and blood sample collection (months) | 7.7 (0.7–40.5) |
Data are medians [25–75th percentile] for continuous data and absolute frequencies (%) for count data.
aIncludes one patient with locally advanced disease.
bNGS failed in two plasma samples.
cNo sufficient tumour material was available for NGS testing in 21 cases.