Metformin with standard neoadjuvant chemotherapy in breast carcinoma

Abstract

Background Breast cancer is the most common cancer among women which increases after the age of 35 till it reaches a peak at 55‐64 years. Metformin is a synthetic oral biguanide that has been shown to cause a 30% reduction in the lifetime risk of all cancers in diabetic patients on Metformin. We aimed at evaluating this antineoplastic effect in terms of pathological response, concurrent with standard neoadjuvant chemotherapy in breast cancer. Methodology 60 non‐diabetic breast cancer patients receiving standard neoadjuvant chemotherapy at the breast cancer outpatient clinic, Ain Shams University hospital, were randomized into two arms (30 in each arm); Arm A Group receiving Metformin (850 mg bid) with standard line of neoadjuvant chemotherapy (FEC/Taxotere +/‐ Herceptin). Arm B Control group receiving the standard line of neoadjuvant chemotherapy alone. Results There's a significant difference between Metformin and control arm in terms of response (complete and partial) versus no response (p = 0.03). Response to Metformin was significantly more pronounced in Luminal B subtype breast cancer (p = 0.03) and in grade II (p = 0.03). There's no significant difference in toxicity between both arms; most common toxicities in both arms were vomiting (53.6%), nausea (30.4%) and neutropenia (30.4%) Conclusion Metformin has a significant antineoplastic effect which was measured in this study in terms of significant increase in pathological response concurrently with neoadjuvant chemotherapy in breast cancer compared to giving neoadjuvant chemotherapy alone.