| First author, year | Country | Sample size | Age range and/or mean (SD) | Cancer type | Study design |
| Gao et al., 2022 [47] | China | N = 72 tDCS group, n = 36 (29 M, 7 F) CG, n = 36 (31 M, 5 F) | tDCS group: 52.5 ± 8.6 CG: 53.1 ± 8.2 | Oral cancer | RS |
| Gaynor et al., 2020 [45] | USA | N = 16 (F) | 40–65 years | Breast cancer | PS |
| Knotkova et al., 2014 [42] | USA | N = 1 (F) | 55 years | Breast cancer | SC |
| Nguyen et al., 2016 [39] | France | N = 1 (M) | 80 years | Bladder cancer | SC |
| Stamenkovic et al., 2020 [46] | Serbia | N = 55 tDCS group, n = 27; (16 M, 11 F) Sham group, n = 28; (23 M, 5 F) | tDCS group: 61.44 ± 7.98 Sham group: 61.89 ± 5.79 | Lung cancer | RCT |
| Hu et al., 2016 [34] | USA | N = 98 tDCS group, n = 5 (4 M, 1 F) CG, n = 93 (retrospective data) | 62.6 ± 5 | Head and neck cancer | PS |
| Kamal et al., 2022 [43] | Egypt | N = 60 (F) tDCS group, n = 30 Sham group, n = 30 | tDCS group: 48.4 ± 6.6 Sham group: 50.4 ± 5.7 | Breast cancer | RCT |
| Ibrahim et al., 2018 [44] | Egypt | N = 40 tDCS group, n = 20 (n.a.) Sham group, n = 20 (n.a.) | tDCS group: 58.9 ± 5.6 Sham group: 56.85 ± 9.16 | HCC | RCT |
| Mirski et al., 2015 [40] | Poland | N = 1 (F) | 45 years | Meningioma | SC |
| Silva et al., 2007 [41] | Brazil | N = 1 (F) | 65 years | Pancreatic cancer | SC |
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