Impact of preexisting type 2 diabetes mellitus and antidiabetic drugs on all-cause and cause-specific mortality among Medicaid-insured women diagnosed with breast cancer

Antidiabetic Drugs in Breast Cancer Patients

Diabetes is one of the leading chronic conditions worldwide, and breast cancer is the most prevalent cancer in women worldwide. The linkage between diabetes and its ability to increase the risk of breast cancer should always be analyzed in patients. This review focuses on the impact of antihyperglycemic therapy in breast cancer patients. Patients with diabetes have a higher risk of developing cancer than the general population. Moreover, diabetes patients have a higher incidence and mortality of breast cancer. In this review, we describe the influence of antidiabetic drugs from insulin and metformin to the current and emerging therapies, incretins and SGLT-2 inhibitors, on breast cancer prognosis. We also emphasize the role of obesity and the metastasis process in breast cancer patients who are treated with antidiabetic drugs.

Influence of type 2 diabetes mellitus on mortality in women with breast cancer: A matched case-control study

AIMS

The study assessed the association between the presence of type2 diabetes mellitus (T2DM) and mortality in women with breast cancer (BC).

METHODS

A matched pair case-control study was conducted at the State Cancer Center, which is located in Xalapa, Veracruz, Mexico. It was matched by age (±3 years) within a cohort of 1442 patients with BC. Descriptive statistics were performed. Analysis through paired odds ratio (OR and multivariate analyses were used to calculate the association between BC mortality and the variables studied.

RESULTS

166 cases and 166 controls with confirmed diagnosis of BC were studied, with a mean age of 52.9 ± 11.9 years. The T2DM was associated with an increased mortality of women with BC (OR = 1.75 95 %CI 1.06-2.89). Similarly, metastasis (OR = 14.17 95 %CI 6.19-32.342), advanced clinical stage (OR = 3.04 95 %CI 1.45 - 6.38), and the molecular subtypes Her2 (OR = 2.0 95 %CI 1.02-3.92), and triple negative (OR = 3.54 95 %CI 1.72-7.32). There was no difference in mean glucose between cases and controls (208.9 ± 132 vs 194.4 ± 90.4 mg/dL, respectively).

CONCLUSION

T2DM was found to be a relevant risk factor for BC mortality in this Mexican population. Thus, it is important to consider the presence and evolution of DM in the prevention programs, diagnostic algorithms and treatments established for BC.

Systemic Evaluation of the Effect of Diabetes Mellitus on Breast Cancer in a Mouse Model

Breast cancer complicated with diabetes mellitus (DM) is a common disease. To evaluate the effect of preexisting DM on breast cancer progression without drug interference, we used a streptozotocin (STZ)-induced type 2 diabetes mellitus BALB/c mouse model. We found that 4T1 breast cancer complicated with DM decreased the mouse survival time compared with 4T1-bearing mice. The diversity of gut microbiome was affected by DM. The infiltration of mucosal-associated invariant T cell (MAIT), CD8+ T cell, and CD4+ T cell in the tumor was significantly decreased in the DM-4T1 group compared with the 4T1 group. The transcriptome data of tumor tissues indicated that the expressions of inflammatory C–C chemokine- and metabolism-related genes were greatly changed. The abnormal expression of these genes may be related with the decreased T-cell infiltration in DM-4T1. In conclusion, the gut microbiome and tumor microenvironment of diabetic breast cancer patients have unique features. The effect of diabetes on breast cancer should be considered in the treatment for diabetic breast cancer patients.

Metformin and Breast Cancer: Where Are We Now?

Breast cancer is the most prevalent cancer and the leading cause of cancer-related death among women worldwide. Type 2 diabetes–associated metabolic traits such as hyperglycemia, hyperinsulinemia, inflammation, oxidative stress, and obesity are well-known risk factors for breast cancer. The insulin sensitizer metformin, one of the most prescribed oral antidiabetic drugs, has been suggested to function as an antitumoral agent, based on epidemiological and retrospective clinical data as well as preclinical studies showing an antiproliferative effect in cultured breast cancer cells and animal models. These benefits provided a strong rationale to study the effects of metformin in routine clinical care of breast cancer patients. However, the initial enthusiasm was tempered after disappointing results in randomized controlled trials, particularly in the metastatic setting. Here, we revisit the current state of the art of metformin mechanisms of action, critically review past and current metformin-based clinical trials, and briefly discuss future perspectives on how to incorporate metformin into the oncologist’s armamentarium for the prevention and treatment of breast cancer.

Potential intrinsic subtype dependence on the association between metformin use and survival in surgically resected breast cancer: a Korean national population-based study

PURPOSE

Numerous studies have suggested that metformin treatment can increase breast cancer survival; however, it is unclear whether its effects interact with intrinsic subtype or diabetic status. Therefore, we conducted a large nationwide study to assess this in women with surgically resected invasive breast cancer.

METHODS

Patients with newly diagnosed breast cancer between 2007 and 2016 were identified using the national health insurance claims database of South Korea. Metformin or other drug exposures was defined as medication for ≥ 90 days. Breast cancer subtypes were classified into four groups based on hormonal therapy and anti-HER2 treatments.

RESULTS

A total of 117,333 patients were included (median follow-up duration, 90 months). Type 2 diabetes mellitus (T2DM) affected significantly overall survival (OS, 7 years, 89.7% vs. 92.4%, p < 0.001). A significant interaction was found between the use of metformin and insulin in patients with T2DM (p = 0.018). Thus, the subsequent analysis was limited to these patients and propensity score matching was performed. We found significantly increased OS in patients treated with metformin (7-year OS, 88.3% vs. 85.6%, p < 0.001). Interestingly, a significant effect was observed in the hormonal therapy (HT)+/HER2-targeted therapy (Tx)- group (p < 0.001), whereas no specific association was observed in the HT-/HER2 Tx- group (p = 0.220).

CONCLUSIONS

Metformin administration may be associated with reduced mortality in patients with surgically resected breast cancer, particularly in the HT+/HER2 Tx- group. Clinical trials investigating metformin as a combination agent in breast cancer should stratify patients by curative resection, intrinsic subtype, the presence of T2DM, and the use of insulin.

Diabetic mortality risk among cancer patients in the United State SEER population, 1975-2016

BACKGROUND

The focus on diabetic mortality in cancer patients remains superficial. The objective of our study is to identify cancer patients with the highest risk of diabetic mortality compared with other cancer patients and the general US population.

METHODS

The representative data of cancer patients dying from diabetes between 1975 and 2016 was retrieved from the Surveillance, Epidemiology, and End Results program. Standardized mortality ratios (SMRs) and excess risks for multiple cancer sites were calculated. Cox regression analysis was performed to identify potential risk factors of death from diabetes.

RESULTS

Among 9,043,788 cancer patients diagnosed between 1975 and 2016, 51,611 patients died from diabetes. the SMR of diabetic death was 2.15 compared with the general population. Malignancies of pancreas, liver, and brain had the highest SMR (>15) compared with the general population. The risk of death from diabetes was increasing in more recent years. The majority of deaths from diabetes occurred in those >45 years of age diagnosed with prostate, breast, colorectum, lung, or bladder cancer. Patients with older age, male sex, black race, higher histologic grade, unmarried status, and not undergoing surgery are at higher risk compared with other cancer survivors.

CONCLUSIONS

Compared to the general population, cancer patients are at elevated risk of death from diabetes throughout the follow-up period. Elderly, black, unmarried males with distant metastases and without receiving surgery are recommended with earlier detection and more efficient diabetic care, especially for those with prostate, breast, colorectum, lung, or bladder cancer.