Objective: Some studies have shown that metformin inhibits the proliferation of breast cancer (BC) cells via multiple ways. One of these mechanisms is through the indirect control of the IGF-route mediated via the activation of the AMPK-LKB1 pathway in the liver, which leads to a decrease in blood glucose and insulin levels. The objective of this study was to investigate the effects of metformin as adjuvant to chemotherapy on IGF levels in female patients with progressive and non-progressive metastatic BC.
Patients and methods: In this trial, 107 women receiving chemotherapy for metastatic breast cancer (MBC) were divided into two groups: the metformin group received 500 mg of metformin twice daily, whereas the control group did not receive any metformin. All patients received chemotherapy according to the South Egypt Cancer Institute's (SECI) established regimen. The level of IGF-1 was determined in the blood at the initiation of therapy (baseline) and at six months post treatment.
Results: No substantial differences were noted regarding IGF-1 levels in both groups at baseline (IGF-1 average level was 40.74 ± 36.16 vs. 32.06 ± 20.00 in the metformin and the placebo group, respectively, p = 0.462). While after six months, the mean IGF-1 level was 37.62 ± 31.35 vs. 39.12 ± 2 5.93 in the metformin and placebo groups, respectively, (p = 0.170).
Conclusions: Metformin as an adjuvant to chemotherapy in MBC patients had no significant effect on reducing IGF-l levels which promotes the inhibition of the proliferation of BC cells in MBC patients.