Pioglitazone does not affect the risk of kidney cancer in patients with type 2 diabetes

Anti-Diabetic Therapies and Cancer: From Bench to Bedside

Diabetes mellitus (DM) is a significant risk factor for various cancers, with the impact of anti-diabetic therapies on cancer progression differing across malignancies. Among these therapies, metformin has gained attention for its potential anti-cancer effects, primarily through modulation of the AMP-activated protein kinase/mammalian target of rapamycin (AMPK/mTOR) pathway and the induction of autophagy. Beyond metformin, other conventional anti-diabetic treatments, such as insulin, sulfonylureas (SUs), pioglitazone, and dipeptidyl peptidase-4 (DPP-4) inhibitors, have also been examined for their roles in cancer biology, though findings are often inconclusive. More recently, novel medications, like glucagon-like peptide-1 (GLP-1) receptor agonists, dual GLP-1/glucose-dependent insulinotropic polypeptide (GIP) agonists, and sodium-glucose co-transporter-2 (SGLT-2) inhibitors, have revolutionized DM management by not only improving glycemic control but also delivering substantial cardiovascular and renal benefits. Given their diverse metabolic effects, including anti-obesogenic properties, these novel agents are now under meticulous investigation for their potential influence on tumorigenesis and cancer advancement. This review aims to offer a comprehensive exploration of the evolving landscape of glucose-lowering treatments and their implications in cancer biology. It critically evaluates experimental evidence surrounding the molecular mechanisms by which these medications may modulate oncogenic signaling pathways and reshape the tumor microenvironment (TME). Furthermore, it assesses translational research and clinical trials to gauge the practical relevance of these findings in real-world settings. Finally, it explores the potential of anti-diabetic medications as adjuncts in cancer treatment, particularly in enhancing the efficacy of chemotherapy, minimizing toxicity, and addressing resistance within the framework of immunotherapy.

Pioglitazone and breast cancer risk in female patients with type 2 diabetes mellitus: a retrospective cohort analysis

BACKGROUND

Whether pioglitazone may affect breast cancer risk in female diabetes patients is not conclusive and has not been investigated in the Asian populations.

METHODS

The reimbursement database of Taiwan's National Health Insurance was used to enroll an unmatched cohort and a propensity score-matched cohort of ever users and never users of pioglitazone in female patients with newly diagnosed type 2 diabetes during 1999-2008. The patients were alive on January 1, 2009 and were followed up for breast cancer incidence until December 31, 2011. Cox regression was used to estimate hazard ratios for ever users and tertiles of cumulative duration of pioglitazone therapy versus never users, and for cumulative duration of pioglitazone therapy treated as a continuous variable. Three models were created for the unmatched cohort and the matched cohort, respectively: 1) without adjustment for covariates; 2) after adjustment for covariates that differed with statistical significance (P-value < 0.05) between ever users and never users; and 3) after adjustment for all covariates.

RESULTS

There were 174,233 never users and 6926 ever users in the unmatched cohort; and 6926 never users and 6926 ever users in the matched cohort. After a median follow-up of 2.8 years, the numbers of incident breast cancer were 1044 in never users and 35 in ever users in the unmatched cohort and were 41 and 35, respectively, in the matched cohort. Hazard ratios suggested a null association between pioglitazone and breast cancer in all three models in either the unmatched cohort or the matched cohort. The overall hazard ratio after adjustment for all covariates was 0.758 (95% confidence interval: 0.539-1.065) in the unmatched cohort and was 0.824 (95% confidence interval: 0.524-1.296) in the matched cohort. None of the hazard ratios for the tertiles of cumulative duration of pioglitazone therapy and for the cumulative duration being treated as a continuous variable were statistically significant.

CONCLUSIONS

This study suggests a null association between pioglitazone and breast cancer risk in female patients with type 2 diabetes mellitus. However, because of the small breast cancer cases and the limited follow-up time, further studies are warranted to confirm our findings.

Global and Regional Effects of Bladder Cancer Risk Associated with Pioglitazone Therapy in Patients with Diabetes

It has been debated for several years as to whether the antidiabetic drug pioglitazone increases the risk for bladder cancer. A series of recent large population studies yielded conflicting results. To investigate why the observational studies yielded conflicting results, we conducted stratified analyses to analyze the potential confounders behind these discordant outcomes. A total of 2,764,731 participants from observational (OB) studies and 9,999 from randomized control trials (RCTs) were identified for these analyses. The stratified analysis revealed that the study type, adjustment for age/sex, treatment duration, cumulative dose, agents used in a control group, mean period of follow-up and study population region might contribute to the discordant outcomes. In terms of population regions, pioglitazone increased the risk for bladder cancer could be found in European population, and patients who undergo treatment with pioglitazone for longer durations (>12 months) or are administrated a larger cumulative dose (>28,000 mg) might require more attention, and the long-term effects (≥3.6 years) of pioglitazone needs be monitored more carefully.

Cancer risks of anti-hyperglycemic drugs for type 2 diabetes treatment - a clinical appraisal

AIM

A clinical appraisal of existing scientific literature sought to assess the need for long-term prospective epidemiological studies to investigate an increased cancer risk of anti-hyperglycemic medication in type 2 diabetes.

METHOD

A focus statement was formulated as: "With a higher risk of cancers in patients with type 2 diabetes, all anti-hyperglycemic drugs should undergo long-term, prospective epidemiological studies for cancer risks." Field surveys were sent to practicing physicians and endocrinologists to identify the currently prevalent level of acceptance of this statement. Subsequently, a meeting with a six-member panel of key opinion leaders was held to discuss published evidence in support and against the statement. This publication reviews the publications and discussion points brought forth in this meeting and their effect on statement acceptance by the panel.

RESULTS

Whereas the majority of field survey responders primarily agreed with the statement, panel members were divided in their statement support. This division remained intact after review of the literature.

CONCLUSIONS

While there was evidence that type 2 diabetes is associated with an increased risk of cancer, existing studies seemed insufficient to definitively demonstrate a link between cancer risk and use of specific anti-hyperglycemic therapies.

Deciphering the Roles of Thiazolidinediones and PPAR in Bladder Cancer

The use of thiazolidinedione (TZD) therapy in type II diabetic patients has proven useful in the lowering of blood glucose levels. However, recent investigations have shown that there may be potential health concerns associated, including the risk of developing bladder cancer as well as complications in the cardiovasculature. TZDs are ligands for the nuclear receptor PPARγ, and activation causes lipid uptake and insulin sensitization, both of which are critical processes for diabetic patients whose bodies are unable to utilize insulin effectively. Several studies have shown that PPARγ/TZDs decrease IGF-1 levels and, thus, reduce cancer growth in carcinomas such as the pancreas, colon, liver, and prostate. However, other studies have shed light on the potential of the receptor as a biomarker for uroepithelial carcinomas, particularly due to its stimulatory effect on migration of bladder cancer cells. Furthermore, PPARγ may provide the tumor-promoting microenvironment by de novo synthesis of nutrients that are needed for bladder cancer development. In this review, we closely examine the TZD class of drugs and their effects on PPARγ in patient studies along with additional molecular factors that are positive modulators, such as protein phosphatase 5 (PP5), which may have considerable implications for bladder cancer therapy.

Sitagliptin increases acute pancreatitis risk within 2 years of its initiation: A retrospective cohort analysis of the National Health Insurance database in Taiwan

PURPOSE

To evaluate the risk of acute pancreatitis hospitalization with sitagliptin use in patients with type 2 diabetes mellitus (T2DM).

METHODS

This retrospective cohort analysis included newly diagnosed T2DM with onset age ≥25 years between 1999 and 2010 from the National Health Insurance database. Ever users (n = 89,800) and never users (n = 449,000) of sitagliptin were followed until end of 2011. A time-dependent approach was used to calculate event incidence and estimate hazard ratios adjusted for propensity score.

RESULTS

During follow-up, 261 ever users and 5,840 never users were hospitalized for acute pancreatitis (respective incidence, 224.0 and 168.4 per 100,000 person-years), with adjusted hazard ratio of 1.59 (95% CI 1.40-1.81). The respective hazard ratio for the first, second, and third tertile of time since starting sitagliptin <9.5, 9.5-21.0, and >21.0 months was 8.10 (6.80-9.65), 1.70 (1.38-2.11), and 0.41 (0.30-0.56); 3.26 (2.67-3.98), 1.86 (1.52-2.27), and 0.76 (0.59-0.98) for cumulative duration <3.7, 3.7-10.3, and >10.3 months; and 3.21 (2.65-3.90), 1.89 (1.54-2.32), and 0.73 (0.57-0.95) for cumulative dose <9,000, 9,000-28,000, and >28,000 mg.

CONCLUSIONS

Sitagliptin is associated with a higher risk of acute pancreatitis within the first 2 years of its initiation. The risk diminishes thereafter, probably due to the depletion of susceptible patients.

Pioglitazone and the risk of bladder cancer: An Indian retrospective cohort study

AIM

To determine whether pioglitazone is associated with an increased risk of bladder cancer among Indian type 2 diabetic patients.

METHODS

A retrospective data analysis of 2222 type 2 diabetic patients was conducted. The study subjects were divided into two equal groups: 1111 pioglitazone users and 1111 pioglitazone non-users. The safety of pioglitazone therapy was analyzed in terms of occurrence of bladder and other types of cancers along with its efficacy in terms of glycemic control. Parameters for assessing safety were duration of disease, duration of usage and total dose of pioglitazone consumed across age groups, glycemic control, obesity and family history of any cancer. Bladder cancer prevalence was analyzed on the basis of urinary cytology, urine routine and microscopy, hematuria, urinary nuclear matrix protein 22 analysis and ultrasonography.

RESULTS

Of the 2222 cases analysed, there was no evidence of bladder cancer in any of the studied groups, (p=not significant) which was also evident among 1111 patients on Pioglitazone therapy with a cumulative dose consumption of 2737 mg to 1,31,400 mg. On subgroup analysis, there was no evidence of bladder cancer amongst patients with age >60 years, duration of diabetes > 10 years and uncontrolled diabetics (HbA1c >8%) with cumulative pioglitazone consumption of >28,000 mg. A significant number of patients achieved good glycemic control (HbA1c <7.5%) with pioglitazone therapy.

CONCLUSION

Pioglitazone therapy was not associated with occurrence of bladder cancer among Indian type 2 diabetic patients and demonstrated good glycemic control.

Metformin and endometrial cancer risk in Chinese women with type 2 diabetes mellitus in Taiwan

OBJECTIVE

To evaluate metformin effects on endometrial cancer risk in Chinese female patients with type 2 diabetes mellitus (T2DM) in Taiwan.

METHODS

This is a retrospective cohort analysis using the National Health Insurance database of Taiwan. Female patients with newly diagnosed T2DM and without endometrial cancer in 1998-2002 were followed to end of 2009 (n=478,921). Among them, 285,916 were never-users and 193,005 were ever-users of metformin. A time-dependent approach was used to calculate endometrial cancer incidence and estimate hazard ratios by Cox regression for ever-users, never-users, and subgroups of metformin exposure (tertiles of cumulative duration and cumulative dose). Sensitivity analyses were conducted in various subgroups.

RESULTS

During follow-up, 728 metformin ever-users and 2157 never-users developed endometrial cancer, representing an incidence of 60.00 and 121.69 per 100,000 person-years, respectively. The overall hazard ratio (95% confidence intervals) for ever- versus never-users after adjustment for propensity score (PS) was 0.675 (0.614-0.742). The PS-adjusted hazard ratios for the first, second, and third tertiles of cumulative duration of metformin therapy were 1.089 (0.966-1.228), 0.707 (0.616-0.812) and 0.313 (0.262-0.374), respectively (P-trend<0.0001); and 1.062 (0.942-1.197), 0.620 (0.538-0.715) and 0.376 (0.317-0.447), respectively (P-trend<0.0001), for cumulative dose of metformin. The dose-response relationship was demonstrated in various models and an overall reduced risk was consistently supported by sensitivity analyses.

CONCLUSIONS

The use of metformin in women with T2DM was associated with an overall significantly lower risk of endometrial cancer with dose-response relationship.