Table 1.
Patient and sample characteristics of the retrospective metastatic ILC cohort
| N (%) | |
|---|---|
| Age at primary diagnosis | |
| Median (min–max) | 55 (33–81) |
| <50 | 23 (28.8) |
| ≥50 | 57 (71.3) |
| De novo metastatic | |
| No | 66 (82.5) |
| Yes | 14 (17.5) |
| Histological primary tumor size | |
| <2 cm | 20 (25.0) |
| ≥2 cm | 58 (72.5) |
| Unknown | 2 (2.5) |
| Histological nodal status | |
| Negative | 27 (33.8) |
| Positive | 52 (65.0) |
| Unknown | 1 (1.3) |
| Histological grade primary | |
| 1 | 15 (18.8) |
| 2 | 49 (61.3) |
| 3 | 15 (18.8) |
| Unknown | 1 (1.3) |
| PgR status primary | |
| Negative | 11 (13.8) |
| Positive | 66 (82.5) |
| Unknown | 3 (3.8) |
| HER2 status primary | |
| Negative | 67 (83.8) |
| Positive | 6 (7.5) |
| Unknown | 7 (8.8) |
| Ki67 primary | |
| <20% | 38 (47.5) |
| ≥20% | 25 (31.3) |
| Unknown | 17 (21.3) |
| ER status metastasis | |
| Negative | 6 (7.5) |
| Positive | 66 (82.5) |
| Unknown | 8 (10.0) |
| Main histological subtype primary | |
| Alveolar | 1 (1.3) |
| Classic | 45 (56.3) |
| Mixed non-classic (incl. pleomorphic) | 17 (21.3) |
| Solid | 3 (3.8) |
| Trabecular | 13 (16.3) |
| Unknown | 1 (1.3) |
| (Neo)Adjuvant chemotherapy | |
| Yes | 64 (80.0) |
| No | 16 (20.0) |
| Organ metastatic samplea | |
| Bone | 20 (23.5) |
| GI tract | 7 (8.2) |
| Local relapse | 3 (3.5) |
| Liver | 8 (9.4) |
| Lung | 8 (9.4) |
| Lymph nodes | 6 (7.1) |
| Peritoneum | 7 (8.2) |
| Reproductive organs | 13 (15.3) |
| Skin | 13 (15.3) |
| Timing metastatic sample | |
| At first diagnosis metastatic diseaseb | 62 (77.5) |
| After first diagnosis metastatic disease | 18 (22.5) |
| Endocrine treatment before metastatic biopsy | |
| SERM only | 32 (40.0) |
| AI only | 18 (22.5) |
| SERM and AI | 24 (30.0) |
| No endocrine treatment | 6 (7.5) |
| Duration endocrine treatment before metastatic biopsy | |
| <2 years | 21 (26.3) |
| 2 to 4 years | 14 (17.5) |
| >4 years | 45 (56.3) |
AI aromatase inhibitor, ET endocrine therapy, SERM selective estrogen receptor modulator
aThe total number is >80 since several metastatic samples were analyzed for some patients
bThis includes metastatic samples collected up to 3 months after first diagnosis of metastatic disease