Table 1.
Characteristics of included studies
| Author, year | Country | Inclusion period | Median follow-up (months) | Total number of patients (n) | Patients with HER2-low/HER-0 (n) | HR status | Clinical T stage | Clinical N stage | Stage | NOS scale |
|---|---|---|---|---|---|---|---|---|---|---|
| De Moura Leite et al. 2021 [28] | Brazil | 2007–2018 | 59 | 855 | 285/570 | HR + and HR − | T1–T4 | N0–N3 | 1–3 | 8 |
| Denkert et al. 2021 [19] | Europe | 2012–2019 | 47 | 2310 | 1098/1212 | HR + and HR − | T1–T4 | N0–N3 | 1–3 | 8 |
| Kang et al. 2022 [29] | Korea | 2014–2018 | – | 1572 | 754/818 | HR + and HR − | T1–T4 | N0–N3 | 1–3 | 7 |
| Jing‑Jing Li et al. 2023 [30] | China | 2017–2017 | 59 | 283 | 239/44 | HR + and HR − | T1–T4 | N0–N3 | 2–3 | 9 |
| Qiao et al. 2023 [31] | China | 2017–2021 | 20 | 132 | 70/62 | HR + and HR − | – | – | – | 7 |
| Shao et al. 2022 [32] | China | 2017–2019 | – | 314 | 226/88 | HR + and HR − | T1–T4 | N0–N3 | 2–3 | 7 |
| Xu et al. 2023 [33] | China | 2018–2021 | 24 | 429 | 267/162 | HR + and HR − | T1–T4 | N0–N3 | 2–3 | 9 |
| Garufi et al. 2023 [34] | Italy | – | 53 | 566 | 340/226 | HR + | – | – | – | 8 |
| Pöschke et al. 2023 [35] | Germany | 1998–2020 | 240 (20y) | 1373 | 930/443 | HR + and HR − | T1–T4 | N0 − N + | 1–3 | 7 |
| Yang et al. 2023 [36] | China | 2015–2017 | – | 177 | 117/60 | HR + and HR − | T1–T4 | – | – | 8 |
| Dai et al. 2023 [37] | China | 2015–2016 | 71 | 55 | 24/21 | HR + and HR − | – | – | 1–3 | 8 |
| Guochun Zhang et al. 2022 [38] | China | 2016–2017 | – | 87 | 63/24 | HR + and HR − | T1–T4 | N0–N3 | 1–3 | 7 |
| Karakas et al. 2023 [39] | USA | 2020–2021 | 49 | 130 | 75/55 | HR + and HR − | – | – | 1–4 | 9 |
| Ma et al. 2023 [40] | China | 2015–2021 | 55 | 546 | 292/254 | HR − | T1–T4 | N0–N3 | 1–3 | 7 |
| Miglietta et al. 2022 [41] | Italy | 2002–2018 | – | 261 | 105/156 | HR + and HR − | – | – | – | 7 |
| Alves et al. 2022 [42] | Portugal | 2015–2020 | 36 | 72 | 41/31 | HR + and HR − | T1–T4 | N0–N3 | 2–3 | 9 |
| Ilie et al. 2023 [18] | France | 2007–2018 | 54 (4.5y) | 511 | 236/275 | HR + and HR − | T0–T4 | N0–N3 | 1–3 | 8 |
| Zhu et al. 2023 [43] | China | 2009–2020 | 24 | 1473 | 1023/450 | HR + and HR − | – | – | – | 7 |
| Wang et al. 2023 [44] | China | 2018–2022 | 18 | 148 | 93/55 | HR + and HR − | – | – | – | 6 |
| Toss et al. 2022 [45] | Italy | 2008–2020 | 55 | 142 | 82/57 | HR − | T1–T4 | N0 − N + | – | 9 |
| Shi et al. 2023 [46] | China | 2014–2022 | – | 430 | 249/181 | HR + and HR − | T1–T4 | N0 − N + | – | 8 |
| Nonneville et al. 2022 [47] | France | 2005–2021 | 73 | 1111 | 456/655 | HR + and HR − | T0–T4 | N0 − ≥ N1 | 1–3 | 8 |
| Huiyue Li et al. 2023 [48] | USA | 2010–2018 | 65 | 45,331 | 28,172/17159 | HR + and HR − | T1–T4 | N0–N3 | – | 7 |
| Domergue et al. 2022 [49] | France | 2005–2020 | 73 | 437 | 121/316 | HR − | T0–T4 | N0 − ≥ N1 | 1–3 | 9 |
| Di Cosimo et al. 2022 [50] | Italy | 2009–2020 | 60 | 444 | 335/109 | HR + and HR − | – | N0–N3 | 1–3 | 7 |
| Shichao Zhang et al. 2023 [51] | China | 2011–2022 | 40 | 3070 | 2340/730 | HR + | – | – | – | 7 |
| Yi et al. 2023 [52] | China | 2017–2020 | 32 | 86 | 62/24 | HR + and HR − | T1–T4 | N0–N3 | 1–3 | 9 |
| Shiyuan Zhang et al. 2023 [53] | China | 2011–2019 | 67 | 653 | 279/374 | HR + and HR − | T1–T4 | N0–N3 | 1–3 | 8 |
| Reinert et al. 2021 [54] | Brazil | NA | 56 | 331 | 167/164 | HR + and HR − | – | – | – | 7 |
| Yijun Li et al. 2023 [55] | China | 2010–2020 | 1027 | 678/349 | HR + and HR − | T1–T4 | N0–N3 | 1–3 | 9 | |
| Jin et al. 2023 [56] | China | 2013–2019 | 43 | 693 | 561/132 | HR + and HR − | T1–T3 | N0–N3 | – | 9 |
| Douganiotis et al. 2022 [57] | Grece | 2007–2021 | 34 | 113 | 80/33 | HR + | – | – | – | 8 |
| Djurmez et al. 2023 [58] | Serbia | 2020–2021 | – | 75 | 62/13 | HR + and HR − | – | – | – | 8 |
| Tarantino et al. 2024 [59] | USA | 2016–2022 | 35 (2.94y) | 991 | 491/500 | HR + and HR − | – | N0–N3 | – | 9 |
| Tang et al. 2022 [60] | China | 2012–2019 | – | 905 | 685/220 | HR + and HR − | T1–T4 | N0–N3 | – | 7 |
| Zhou et al. 2023 [61] | China | 2016–2021 | 29.3 | 325 | 234/91 | HR + and HR − | T1–T4 | N0–N3 | 1–3 | 8 |
| Shao et al. 2024 [62] | China | 2017–2020 | – | 410 | 293/117 | HR + and HR − | T1–T4 | N0–N3 | 2–3 | 8 |
| Tuluhong et al. 2023 [63] | China | 2008–2019 | 72.7 | 246 | 157/89 | HR + and HR − | T1–T4 | N0–N3 | 1–3 | 7 |
HR hormone receptor; n number; y years; NOS Newcastle–Ottawa scale