Statins and Metformin Improved Survival in Patients With Triple-Negative Breast Cancer

The use of statins and metformin was independently associated with improved survival in patients with early-stage triple-negative breast cancer (TNBC), according to data to be presented at the European Society of Medical Oncology Congress 2025 in Berlin, Germany.

TNBC accounts for roughly 15% of all BC diagnoses in the United States. This aggressive subtype is defined by the absence of estrogen, progesterone, and HER2 expression, leaving patients with limited treatment options. Because these receptors are missing, standard approaches such as chemotherapy, hormone therapy, endocrine therapy, and immunotherapy tend to be far less effective. Preclinical studies show that statins and metformin may exert antitumor effects and improve clinical outcomes.¹

In a retrospective study, researchers found that these agents improved overall survival (OS) and disease-free survival (DFS). The study included 339 female patients with TNBC (median age 47 years; range 40-55), of whom 55.8% had stage 2 disease, 23.9% had stage 3, and 20.4% had stage 1 at diagnosis.²

The researchers collected measurements including age, tumor stage, treatment modalities, and statin and metformin use. Laboratory measures, including hemoglobin, iron, ferritin, and serum lipid profiles, were collected at diagnosis and again 1 year later.²

Researchers then used Kaplan-Meier and multivariable Cox regression analyses to assess how statin and metformin use influenced disease-free and overall survival, accounting for factors such as age, histologic grade, and disease stage. In the study, 18.9% (n = 64) of patients received statins, and 14.5% (n = 49) received metformin.²

The data showed a statistically significant association between statin and metformin and improved DFS and OS (P < .05). Using multivariable analysis, researchers determined statin use was associated with improved DFS (HR: 0.43, 95%CI: (0.20-0.90) P = .026) and OS (HR: 0.41, 95%CI: (0.19-0.85) P = .018); however, metformin outcomes were superior. Metformin use was associated with better DFS (HR: 0.31, 95% CI: (0.11-0.86) P = .025) and OS (HR: 0.40, 95% CI: (0.16-1.02) P = .055, approaching statistical significance).²

The findings support the use of statins and metformin for improved survival in patients with early-stage TNBC, uncovering the potential for drug repurposing. As cancer therapies continue to grow more costly with the development of novel drugs and increasingly complex, aggressive diseases, identifying opportunities to repurpose affordable and accessible treatments has become essential for patients.²

REFERENCES

1. Gerlach A. Sacituzumab govitecan-hziy plus pembrolizumab improves PFS in patients with metastatic triple-negative breast cancer. Pharmacy Times. April 24, 2025. Accessed October 15, 2025. https://www.pharmacytimes.com/view/sacituzumab-govitecan-hziy-plus-pembrolizumab-improves-pfs-in-patients-with-metastatic-triple-negative-breast-cancer

2. Satin S, Sahin T, Guven D, et al. The effect of statin and metformin on survival in early-stage triple-negative breast cancer. Presented at: European Society of Clinical Oncology 2025 Congress. October 17, 2025 to October 15, 2025. Abstract 309P.