Table 3 Studies evaluating survival outcomes of ER-low positive BCs as compared to ER-negative BCs (only studies reporting ER expression in terms of % of ER-positive tumor cells and directly comparing the survival outcomes of ER low positive BC patients with either ER-negative or ER-positive subgroups are here reported; studies reporting ER expression as Allred score or H-score were not included).
ER subgroups | Patients in each subgroup | Relapse outcome definition | Relapse outcome % | Relapse outcome hazard ratio (95% CI) | Relapse outcome p-value | Timepoint of OS evaluation | % OS at timepoint | OS hazard ratio (95% CI) | OS p-value | |
|---|---|---|---|---|---|---|---|---|---|---|
Iwamoto et al. (2012) 4 | ER < 1% | 183a | NR | NR | NR | NR | 8 year- OS | 75% | NR | Ref |
ER1–9% | 25 | NR | NR | NR | NR | 8 year- OS | 80% | NR | p = 0.21 | |
Raghav et al. (2013) 16 | ER < 1% | 897 | 3 year-RFS | 64% | Ref | Ref | 3 year-OS | 79% | Ref | Ref |
ER1–5% | 241 | 3 year-RFS | 67% | 1.11 (0.88–1.41) | p = 0.37 | 3 year-OS | 81% | 1.10 (0.84–1.44) | p = 0.47 | |
ER6–10% | 119 | 3 year-RFS | 77% | 0.92 (0.65–1.30) | p = 0.64 | 3 year-OS | 88% | 0.88 (0.6–1.31) | p = 0.54 | |
Balduzzi et al. (2014) 17 | ER < 1% | 1300 | 5 year-DFS | 74% | 1.40 (0.92–2.12) | p = 0.115 | 5 year-OS | 86% | 1.50 (0.82–2.77) | p = 0.192 |
ER1–10% | 124 | 5 year-DFS | 79% | Ref b | Ref b | 5 year-OS | 90% | Ref b | Ref b | |
Yi et al. (2014) 24 | ER < 1% | 1625a | RFS (no timepoint) | NR | 1.2 (0.9–1.7) | p = 0.2 | OS (no timepoint) | NR | 1.5 (1.1–2) | p = 0.02 |
ER1–9% | 250 | RFS (no timepoint) | NR | Ref b | Ref b | OS (no timepoint) | NR | Ref b | Ref b | |
Fujii et al. (2017) 7 | ER < 1% | 932 | TTR (no timepoint) | NR | 1.64 (1.34–1.99)c | p < 0.001c | OS (no timepoint) | NR | 2.07 (1.67–2.58)c | p < 0.001c |
ER1–9% | 171 | TTR (no timepoint) | NR | 1.92 (1.40–2.62)c | p < 0.001c | OS (no timepoint) | NR | 2.35 (1.66–3.32)c | p < 0.001c |
