Table 2.
Metformin use and survival outcomes of breast cancer patients.
| Reference | Study design | Study populationa | BC type | Mean age (years) | Metformin versus non-metformin | Study findings |
|---|---|---|---|---|---|---|
| Currie et al., 2012 [82] | Retrospective | 1182 | All | NA | NA | OS: HR 0.96 (95% CI: 0.67–1.37) |
|
| ||||||
| Bayraktar et al., 2012 [83] | Retrospective | 130 | Triple negative | 52 | 63 versus 67 | RFS: HR: 1.37 (95% CI: 0.78–2.40) OS: HR: 1.22 (95% CI: 0.66–2.28) |
|
| ||||||
| He et al., 2012 [84] | Retrospective | 154 | HER2+ | 55 | 88 versus 66 | OS: HR 0.52 (95% CI: 0.28–0.97) |
|
| ||||||
| Peeters et al., 2013 [85] | Retrospective | 1058 | All | NA | 508 versus 550 | OS: HR 0.74 (95% CI: 0.58–0.96) |
|
| ||||||
| Lega et al., 2013 [86] | Population-based | 2361 | All | 77 | 1094 versus 1267 | OS: HR 0.97 (95% CI: 0.92–1.02) |
|
| ||||||
| Hou et al., 2013 [87] | Retrospective | 1013 | All | NA | 419 versus 594 | NAb |
|
| ||||||
| Oppong et al., 2014 [88] | Retrospective | 145 | All | 61 | 76 versus 65 | RFS: HR 0.86 (95% CI: 0.38–1.90) |
|
| ||||||
| Xiao et al., 2014 [89] | Retrospective | 680 | Luminal | NA | 275 versus 405c | OS luminal A: HR 3.58 (95% CI: 1.51–8.51) OS luminal B (Ki67): HR 3.23 (95% CI: 1.84–5.68) OS luminal B (Her2+): HR 2.034 (95% CI: 1.02–4.06) |
|
| ||||||
| Kim et al., 2015 [90] | Retrospective | 386 | ER/PR status Her2 status |
55/59 | 202 versus 184 | CSS ER+/PR+ Her2+: HR 6.51 (95% CI: 2.06–20.6) DFS ER+/PR+ Her2+: HR 5.37 (95% CI: 1.88–15.3) |
|
| ||||||
| Vissers et al., 2015 [91] | Retrospective | 1057 | All | 71 | 688 versus 369 | OS: HR 0.47 (95% CI: 0.26–0.82) |
BC: breast cancer; NA: not available; OS: overall survival; HR: hazard ratio; RFS: relapse-free survival; ER: estrogens receptors; PR: progesterone receptors; CSS: cancer specific survival; DFS: disease-free survival.
WHI: Women's Health Initiative, comprising four clinical trials and an observational study; aIncluding only breast cancer patients with diabetes; bHR 0.76 (95% CI: 0.6–0.99) for OS of metformin-treated patients compared to nondiabetic patients.
cNon-metformin versus metformin group.