Within-class differences in cancer risk for sulfonylurea treatments in patients with type 2 diabetes (ZODIAC-55) - a study protocol

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.

Is Gliclazide Associated with a Lower Obesity-Related Cancer Risk Compared to Other Sulfonylureas? A Long-term Prospective Cohort Study

BACKGROUND

Gliclazide has been suspected to be associated with a lower obesity-related cancer risk; however, current evidence is limited by important methodologic shortcomings. This study aimed to evaluate whether gliclazide is preferred over other sulfonylureas regarding obesity-related cancer risk.

METHODS

In this prospective cohort study, an annual benchmarking database in Dutch primary care (Zwolle Outpatient Diabetes project Integrating Available CareZODIAC, 1998-2014) was linked to the Netherlands Cancer Registry and the Dutch Personal Record Database. Of the 71,648 patients with type 2 diabetes, we included 26,207 who used sulfonylureas and had no history of cancer or insulin use at baseline. Obesity-related cancer was defined using the latest definition of the World Cancer Research Fund. Cox regression analyses were used to estimate HRs, with both baseline sulfonylurea and cumulative exposure modeled and corrected for baseline covariates.

RESULTS

During follow-up for 167,692 person-years, there were 1,111 obesity-related cancer events. For males, the adjusted HRs [95% confidence interval (CI)] for baseline sulfonylurea compared with gliclazide were as follows: glibenclamide, 1.10 (0.92-2.69); glimepiride, 1.13 (0.68-1.84); and tolbutamide, 0.93 (0.59-1.48). For females, these were as follows: glibenclamide, 1.49 (0.72-3.13); glimepiride, 0.96 (0.59-1.54); and tolbutamide, 0.84 (0.54-1.28). The adjusted HRs (95% CI) for one more year of cumulative exposure compared with gliclazide were as follows: glibenclamide, 0.90 (0.71-1.14); glimepiride, 0.96 (0.87-1.06); and tolbutamide, 1.00 (0.92-1.09). For females, these were as follows: glibenclamide, 0.93 (0.77-1.13); glimepiride, 0.99 (0.90-1.10); and tolbutamide, 1.04 (0.96-1.13).

CONCLUSIONS

Obesity-related cancer risk was comparable between gliclazide and other sulfonylureas.

IMPACT

Gliclazide is not preferred over other sulfonylureas regarding obesity-related cancer risk.

Monotherapy with Metformin versus Sulfonylureas and Risk of Cancer in Type 2 Diabetic Patients: A Systematic Review and Meta-Analysis

BACKGROUND

Accumulating evidence suggests that patients with type 2 diabetes mellitus and hyperinsulinemia are at an increased risk of developing malignancies. It remains to be fully elucidated whether the use of metformin, an insulin sensitizer, and/or sulfonylureas, insulin secretagogues, affects cancer incidence in subjects with type 2 diabetes mellitus.

OBJECTIVE

A systematic review and meta-analysis was performed to compare the risk of cancer incidence associated with monotherapy with metformin compared with monotherapy with sulfonylureas in type 2 diabetes mellitus patients.

METHODS

Search was performed throughout MEDLINE/PubMed, EMBASE, Google Scholar, Cochrane Central Register of Controlled Trials (CENTRAL), and ClinicalTrials.gov up until December 2018. In this meta-analysis, each raw data (unadjusted) and study-specific (adjusted) relative risks (RRs) was combined and the pooled unadjusted and adjusted RRs with the 95% CI were calculated using the random-effects model with inverse-variance weighting. Heterogeneity among the studies was evaluated using I ² statistics. Publication bias was evaluated using the funnel plot asymmetry test. The Newcastle-Ottawa scale (NOS) was used to assess the study quality.

RESULTS

A total of 8 cohort studies were included in the meta-analysis. Obvious heterogeneity was noted, and monotherapy with metformin was associated with a lower risk of cancer incidence (unadjusted RR = 0.74, 95% CI: 0.55-0.99, I ² = 97.89%, p < 0.00001; adjusted RR = 0.76, 95% CI: 0.54-1.07, I ² = 98.12%, p < 0.00001) compared with monotherapy with sulfonylurea, using the random-effects model with inverse-variance weighting.

CONCLUSIONS

According to this review, the monotherapy with metformin appears to be associated with a lower risk of cancer incidence than monotherapy with sulfonylurea in patients with type 2 diabetes. This analysis is mainly based on cohort studies, and our findings underscore the need for large-scale randomized controlled trials to establish the effect of metformin monotherapy, relative to sulfonylureas monotherapy on cancer.