Table 2.
Study cohort clinical features
| Overall (n = 322) | ER+HER2− (n = 219, 68%) | HER2+ (n = 38, 12%) | TNBC (n = 65, 20%) | P value | |
|---|---|---|---|---|---|
| Median age at primary diagnosis (range) | 46 (23–74) | 46 (24–73) | 43.5 (34–74) | 47 (23–74) | |
| Median age at metastatic diagnosis (range) | 51 (24–78) | 52 (30–78) | 45.5 (35–67) | 50 (24–76) | |
| Median age at consent (range) | 52 (24–81) | 54 (30–78) | 48 (36–81) | 52 (24–77) | |
| Median DFI1 (range) | 40 (1–312) | 54.5 (1–312) | 25 (4–136) | 23 (1–252) | |
| De novo patients | 71 (22%) | 50 (22%) | 14 (36%) | 7 (11%) | |
| Treatment history | |||||
| Previous chemotherapy | |||||
| Yes | 309 (96%) | 208 (95%) | 37 (97%) | 64 (98%) | |
| No | 8 (2%) | 7 (3%) | 1 (3%) | 0 | |
| Unknown | 5 (2%) | 4 (2%) | 0 | 1 (2%) | |
| Previous Endocrine therapy | Chi squared: < 0.0001 | ||||
| Yes | 222 (69%) | 205 (94%) | 11 (29%) | 6 (9%) | |
| No | 95 (29%) | 10 (5%) | 27 (71%) | 58 (89%) | |
| Unknown | 5 (2%) | 4 (1%) | 0 | 1 (2%) | |
| Lines of treatment in metastatic setting | Chi squared: 0.003 | ||||
| 1 | 28 (9%) | 12 (5%) | 1 (3%) | 16 (25%) | |
| 2 | 70 (22%) | 47 (21%) | 4 (11%) | 19 (29%) | |
| 3 | 72 (22%) | 45 (21%) | 13 (34%) | 14 (22%) | |
| > 3 | 133 (41%) | 103 (47%) | 20 (53%) | 10 (15%) | |
| Unknown | 20 (6%) | 12 (5%) | 0 | 6 (9%) | |
| Sequenced patients | |||||
| Sequenced | 234 (72%) | 162 (75%) | 25 (66%) | 47 (72%) | |
| Not sequenced due to sample failure | 18 (6%) | 12 (6%) | 1 (3%) | 5 (8%) | |
| Not sequenced due to other2 | 70 (22%) | 45 (19%) | 12 (31%) | 13 (20%) | |
| Patients with actionable mutations3 | 171 (74%) | 131 (80%) | 11 (44%) | 29 (61%) | Chi squared: 0.0001 |
| Level 1: | 114 (49%) | 93 (57%) | 6 (24%) | 15 (32%) | |
| Level 2 | 57 (25%) | 38 (24%) | 5 (20%) | 14 (30%) | |
| No actionable alterations | 63 (26%) | 31 (19%) | 14 (56%) | 18 (38%) | |
DFI disease-free interval (time in months)
1Patients with de novo metastatic disease not included. 2Other reasons for not being sequenced aside from sequencing failure include: sample not received or insufficient DNA quantity for sequencing. 3Percentage calculated from number of sequenced patients. Numbers shown are reflective of the overall total and then the total within each subtype. The HER2+ subtype does not include patients with ERBB2 amplification (100%, n = 25)