Association of antidiabetic medication and statins with breast cancer incidence in women with type 2 diabetes

The association between acute myocardial infarction and subsequent diagnosis of breast cancer: a nationwide, population-based cohort study

Coronary artery disease (CAD) such as acute myocardial infarction (MI) share several common risk factors with cancers, and each disease may influence the prognosis of the other. Recently, acute MI was demonstrated to accelerate the outgrowth of preexisting breast cancer cells but the risk of breast cancer after MI remains unclear. This study aimed to investigate the association between acute MI and a subsequent diagnosis of breast cancer. Female patients with and without a history of acute MI were identified from nationwide databases in Taiwan. Patients with a diagnosis of cancer, MI or CAD prior to the study period were excluded. After reducing confounding through inverse probability of treatment weighting, we compared the incidence of newly diagnosed breast cancer between patients with a history of acute MI and those without. As a result, a total of 66,445 female patients were obtained, including 15,263 patients with a history of acute MI and 51,182 patients without. The incidences of breast cancer during follow-up were 1.93 (95% confidence interval [CI] 1.78-2.09) and 1.80 (95% CI 1.67-1.93) per 1,000 person-years for patients with and without a history of acute MI, respectively. The hazard ratio (HR) was 1.05 (95% CI 0.78-1.41, P = 0.756). In subgroup analysis, breast cancer risk was significantly associated with acute MI in patients using antidiabetic drugs (HR 1.27; 95% CI 1.02-1.58) and in low to moderate urbanization levels (HR 1.28; 95% CI 1.06-1.53). In conclusion, the risk of newly diagnosed breast cancer was not increased in patients with acute MI when compared to general population without MI or CAD.

Statin use as a moderator on the association between metformin and breast cancer risk in women with type 2 diabetes mellitus

INTRODUCTION

Metformin and statins are considered as potential agents for prevention of breast cancer, however, existing evidence does not uniformly substantiate this claim, and the data is scarce concerning their interaction in relation to breast cancer risk. This study aims to investigate whether the effect of metformin on breast cancer incidence varied by statin use among women with type 2 diabetes mellitus (T2DM).

METHODS

This study included women with T2DM, without a history of cancers, and followed up for more than one year from the Zwolle Outpatient Diabetes project Integrating Available Care (ZODIAC) for the period 1998-2014. The dataset was structured using a person-time approach, where the cumulative medication usage was annually updated for each person. The extended Cox proportional hazards models were employed, reporting adjusted hazard ratios (HR) with 95% confidence intervals (CI).

RESULTS

During a median follow-up of 5 years, 515 of 29,498 women received a breast cancer diagnosis. Each additional year of metformin or statins use corresponded to a decrease in breast cancer incidence, while the magnitude attenuated over time. Noteworthily, statin use modified the effect of metformin on breast cancer incidence. For instance, after 5 years of follow-up, one-year increase of metformin use among women who used statins for 3 years was linked to a substantially reduced breast cancer risk (HR, 95% CI: 0.88, 0.84-0.93), however, there was no significant decrease in risk for those non-statins users (HR, 95% CI: 0.96, 0.89-1.04).

CONCLUSIONS

Extending metformin or statin usage by one year conferred breast cancer protection in women with T2DM. Enhanced protective effect of metformin was observed among those who also use statins. These results suggest the potential of combined metformin and statin therapy as promising breast cancer prevention strategies.

Metformin: A Dual-Role Player in Cancer Treatment and Prevention

Cancer continues to pose a significant global health challenge, as evidenced by the increasing incidence rates and high mortality rates, despite the advancements made in chemotherapy. The emergence of chemoresistance further complicates the effectiveness of treatment. However, there is growing interest in the potential of metformin, a commonly prescribed drug for type 2 diabetes mellitus (T2DM), as an adjuvant chemotherapy agent in cancer treatment. Although the precise mechanism of action of metformin in cancer therapy is not fully understood, it has been found to have pleiotropic effects, including the modulation of metabolic pathways, reduction in inflammation, and the regulation of cellular proliferation. This comprehensive review examines the anticancer properties of metformin, drawing insights from various studies conducted in vitro and in vivo, as well as from clinical trials and observational research. This review discusses the mechanisms of action involving both insulin-dependent and independent pathways, shedding light on the potential of metformin as a therapeutic agent for different types of cancer. Despite promising findings, there are challenges that need to be addressed, such as conflicting outcomes in clinical trials, considerations regarding dosing, and the development of resistance. These challenges highlight the importance of further research to fully harness the therapeutic potential of metformin in cancer treatment. The aims of this review are to provide a contemporary understanding of the role of metformin in cancer therapy and identify areas for future exploration in the pursuit of effective anticancer strategies.

Metformin and Breast Cancer: Current Findings and Future Perspectives from Preclinical and Clinical Studies

Over the last several decades, a growing body of research has investigated the potential to repurpose the anti-diabetic drug metformin for breast cancer prevention and/or treatment. Observational studies in the early 2000s demonstrated that patients with diabetes taking metformin had decreased cancer risk, providing the first evidence supporting the potential role of metformin as an anti-cancer agent. Despite substantial efforts, two decades later, the exact mechanisms and clinical efficacy of metformin for breast cancer remain ambiguous. Here, we have summarized key findings from studies examining the effect of metformin on breast cancer across the translational spectrum including in vitro, in vivo, and human studies. Importantly, we discuss critical factors that may help explain the significant heterogeneity in study outcomes, highlighting how metformin dose, underlying metabolic health, menopausal status, tumor subtype, membrane transporter expression, diet, and other factors may play a role in modulating metformin's anti-cancer effects. We hope that these insights will help with interpreting data from completed studies, improve the design of future studies, and aid in the identification of patient subsets with breast cancer or at high risk for the disease who are most likely to benefit from metformin treatment.

Prognostic value of metformin in cancers: An updated meta-analysis based on 80 cohort studies

BACKGROUND

Experiments have shown that metformin can inhibit cancer cell growth, but clinical observations have been inconsistent, so we pooled the currently available data to evaluate the impact of metformin on cancer survival and progression.

METHODS

PubMed, web of science, Embase, and Cochrane databases were searched. Pooled hazard ratios (HRs) were identified using a random-effects model to estimate the strength of the association between metformin and survival and progression in cancer patients.

RESULTS

We incorporated 80 articles published from all databases which satisfied the inclusion criterion. It showed that metformin was associated with better overall survival (hazard ratio [HR] = 0. 81; 95% confidence interval [CI]: [0.77-0.85]) and cancer-specific survival (HR = 0.79; 95% CI: [0.73-0.86]), and metformin was associated with progression-free survival (HR = 0.76; 95% CI: [0.66-0.87]). In patients with diabetes mellitus, the HR of overall survival was 0.79(95% CI: [0.75-0.83]), progression-free survival was 0.72(95% CI: [0.60-0.85]), and the cancer-specific survival was 0.76(95% CI: [0.68-0.86]). It was proposed that metformin can improve the prognosis of cancer patients with diabetes mellitus.

CONCLUSION

Based on cohort studies, metformin therapy has potential survival benefits for patients with malignancy, especially with the greatest benefits seen in breast cancer on overall survival, progression-free survival, and cancer-specific survival. And metformin also showed potential benefits in cancer-specific survival in colorectal and prostate cancer.

Effect of statins use on risk and prognosis of breast cancer: a meta-analysis

The findings regarding the association between statins use and breast cancer are inconsistent. Given the widely and long-term use of statins as first choice drug for dyslipidemia, we conducted this meta-analysis for better understanding the associations between statins use and the risk and prognosis of breast cancer. Articles regarding effect of statins use on risk, prognosis of breast cancer and published before January 2021 were searched in the following databases: Web of Science, PubMed, EMBASE, Medline and Google Scholar. Odds ratios (ORs)/relative risks (RRs) or hazard ratios (HRs) and their 95% confidence intervals (CIs) were computed to generate a pooled effect size and 95% CI. The meta-analysis showed no significant association between statins use and risk of breast cancer (OR/RR = 1.02; 95% CI, 0.97-1.08; I2 = 76.1%; P < 0.001). The meta-analysis showed that statins use was associated with lower breast cancer recurrence, all-cause mortality and disease-specific mortality (breast cancer recurrence: HR = 0.75; 95% CI, 0.67-0.84; I2 = 31.7%; P = 0.154; all-cause mortality: HR = 0.82; 95% CI, 0.77-0.89; I2 = 67.5%; P < 0.001; and disease-specific mortality: HR = 0.82; 95% CI, 0.72-0.93; I2 = 83.6%; P < 0.001). Overall, in this report we demonstrated that the use of statins can improve the prognosis of breast cancer patients including lower risks of breast cancer recurrence, all-cause and cancer-specific mortality, though statins therapy may not have an impact on reducing the risk of breast cancer.

Metformin and risk of cancer among patients with type 2 diabetes mellitus: A systematic review and meta-analysis

AIM

We carried out this meta-analysis on all published studies to estimate the overall cancer risk of the use of metformin in T2DM patients.

METHODS

We searched the PubMed, Embase and CNKI databases for all articles within a range of published years from 2007 to 2019 on the association between the use of metformin and cancer risk in T2DM patients. The odds ratio (OR) corresponding to the 95% confidence interval (95% CI) was used to assess the association using a random-effect meta-analysis.

RESULTS

Finally, 67 studies met the inclusion criteria for this study, with 10,695,875 T2DM patients and 145,108 cancer cases. Overall, For T2DM patients of ever vs. never metformin users, there was statistical evidence of significantly decreased cancer risk was found to be associated with ever metformin users (OR=0.70, 95% CI=0.65-0.76). Considering T2DM may be a specific and independent risk factor for various forms of cancer, due to its particular metabolic characteristics of glucose intolerance and hyperinsulinemia, we performed a comparison to estimate the effects of metformin on cancer risk with other anti-diabetes medications (ADMs), our results found significantly decreased cancer risk to be associated with the use of metformin (OR=0.80, 95% CI=0.73-0.87).

CONCLUSION

Our meta-analysis indicated that metformin may be a independent protective factor for cancer risk in T2DM patients.

Statins: HMG-CoA Reductase Inhibitors as Potential Anticancer Agents against Malignant Neoplasms in Women

Statins, also known as HMG-CoA inhibitors, are a class of bioactive small molecules that efficiently reduce the levels of cholesterol, and therefore are commonly used to manage and prevent various cardiovascular diseases. With respect to their original medical indications, statins are currently in the group of the most prescribed drugs worldwide. Of note is that statins are perceived actually rather as agents that have pleiotropic activities; in addition to their inhibitory activity on the production of endogenous cholesterol. Statins may also affect cell proliferation, angiogenesis and/or migration (metastasis) of different cancer cells, and play a positive role in the chemoprevention of cancer, thus being the excellent candidates to be repurposed in oncology. Particularly intriguing in this context seems to be the promising role of statins on both the incidence and course of common malignant neoplasms in women. In this article, we review and discuss the effect of the use of statins in the treatment of three types of cancer, i.e., breast, endometrial and ovarian cancer, with the highest mortality among gynecological cancers.

Independent and joint cross-sectional associations of statin and metformin use with mammographic breast density

BACKGROUND

Well-tolerated and commonly used medications are increasingly assessed for reducing breast cancer risk. These include metformin and statins, both linked to reduced hormone availability and cell proliferation or growth and sometimes prescribed concurrently. We investigated independent and joint associations of these medications with mammographic breast density (MBD), a useful biomarker for the effect of chemopreventive agents on breast cancer risk.

METHODS

Using data from a cross-sectional study of 770 women (78% Hispanic, aged 40-61 years, in a mammography cohort with high cardiometabolic burden), we examined the association of self-reported "ever" use of statins and metformin with MBD measured via clinical Breast Imaging Reporting and Data System (BI-RADS) density classifications (relative risk regression) and continuous semi-automated percent and size of dense area (Cumulus) (linear regression), adjusted for age, body mass index, education, race, menopausal status, age at first birth, and insulin use.

RESULTS

We observed high statin (27%), metformin (13%), and combination (9%) use, and most participants were overweight/obese (83%) and parous (87%). Statin use was associated with a lower likelihood of high density BI-RADS (RR = 0.60, 95% CI = 0.45 to 0.80), percent dense area (PD) (β = - 6.56, 95% CI = - 9.05 to - 4.06), and dense area (DA) (β = - 9.05, 95% CI = - 14.89 to - 3.22). Metformin use was associated with lower PD and higher non-dense area (NDA), but associations were attenuated by co-medication with statins. Compared to non-use of either medication, statin use alone or with metformin were associated with lower PD and DA (e.g., β = - 6.86, 95% CI: - 9.67, - 4.05 and β = - 7.07, 95% CI: - 10.97, - 3.17, respectively, for PD) and higher NDA (β = 25.05, 95% CI: 14.06, 36.03; β = 29.76, 95% CI: 14.55, 44.96, respectively).

CONCLUSIONS

Statin use was consistently associated with lower MBD, measured both through clinical radiologist assessment and continuous relative and absolute measures, including dense area. Metformin use was associated with lower PD and higher NDA, but this may be driven by co-medication with statins. These results support that statins may lower MBD but need confirmation with prospective and clinical data to distinguish the results of medication use from that of disease.