Effect of metformin use on the risk and prognosis of colorectal cancer in diabetes mellitus: a meta-analysis

Associations of diabetes and mortality among colorectal cancer patients from the Southern Community Cohort Study

BACKGROUND

We investigated associations between diabetes and mortality among participants with incident colorectal cancer (CRC) from the Southern Community Cohort Study.

METHODS

Participants (73% non-Hispanic Black; 60% income < $15,000) were recruited between 2002-2009. Diabetes was self-reported at enrollment and follow-up surveys at approximately 5-year intervals. Incident CRC and mortality were identified via state registries and the National Death Index. Proportional hazards models calculated associations between diabetes with overall, CRC-specific mortality among 1059 participants with incident CRC.

RESULTS

Diabetes prior to diagnosis is associated with elevated overall (hazard ratio [95% confidence interval]: (1.46[1.22-1.75]), and CRC-specific mortality (1.36[1.06-1.74])) after adjustment for tumor stage. For non-Hispanic Black and non-Hispanic White participants, consistent associations were observed for overall (1.35[1.10-1.66] vs. 1.89[1.31-2.72], respectively, p-interaction = 0.11) and CRC-specific mortality (1.30[0.99-1.71] vs. 1.77[1.06-2.95], respectively, p-interaction = 0.28). For individuals with incomes <$15,000/year, associations with overall (1.44[1.15-1.79]) and CRC-specific mortality (1.28[0.94-1.73]) were similar to the full sample. Associations with overall (1.71[1.37-2.13]) and CRC-specific mortality (1.65[1.22-2.22]) were highest for diabetes ≥ 10 years at diagnosis.

CONCLUSIONS

Pre-diagnosis diabetes is associated with higher mortality among participants with incident CRC from a predominantly non-Hispanic Black cohort with lower socioeconomic status. The higher prevalence of diabetes in this population may contribute to racial disparities in CRC mortality.

Metformin's role in lowering colorectal cancer risk among individuals with diabetes from the Southern Community Cohort Study

BACKGROUND

Metformin, utilized to manage hyperglycemia, has been linked to a reduced risk of colorectal cancer (CRC) among individuals with diabetes. However, evidence is lacking for non-Hispanic Black individuals and those with lower socioeconomic status (SES), who face elevated risk for both diabetes and CRC. In this study, we investigated the association between metformin use and incident CRC risk within the Southern Community Cohort Study (SCCS), a racially- and SES-diverse prospective cohort.

METHODS

Participants reported their diabetes diagnosis and medications, including metformin, upon enrollment (2002-2009) and during follow-up surveys approximately every five years. Incident cases of CRC were identified through state cancer registries and the National Death Index. Proportional hazards models were employed to explore the relationship between metformin use and CRC risk, adjusted for cancer risk factors.

RESULTS

A total of 25,992 participants with diabetes were included in the analysis, among whom 10,095 were taking metformin. Of these participants, 76% identified as non-Hispanic Black, and 60% reported household incomes <$15,000/year. Metformin use was associated with a significantly lower CRC risk (HR [95% CI]: 0.71 [0.55-0.93]), with consistent results for both colon (0.80 [0.59-1.07]) and rectal cancers (0.49 [0.28-0.86]). The protective association appeared to be stronger among non-Hispanic White individuals (0.51 [0.31-0.85]) compared to non-Hispanic Black participants (0.80 [0.59-1.08], p-interaction =.13). Additionally, a protective association was observed among obese individuals (BMI ≥30 kg/m2, 0.59 [0.43-0.82] but not among non-obese participants (0.99 [0.65-1.51], p-interaction =.05) CONCLUSION: Our findings indicate that metformin use is associated with a reduced risk of CRC in individuals with diabetes, including among those from predominantly low SES backgrounds. These results support previous epidemiological findings, and demonstrate that the protective association for metformin in relation to incident CRC likely generalizes to populations with higher underlying risk.

Metabolic Alteration Bridging the Prediabetic State and Colorectal Cancer

Prediabetes and colorectal cancer (CRC) represent compelling health burdens responsible for high mortality and morbidity rates, sharing several modifiable risk factors. It has been hypothesized that metabolic abnormalities linking prediabetes and CRC are hyperglycemia, hyperinsulinemia, and adipokines imbalance. The chronic stimulation related to these metabolic signatures can favor CRC onset and development, as well as negatively influence CRC prognosis. To date, the growing burden of prediabetes and CRC has generated a global interest in defining their epidemiological and molecular relationships. Therefore, a deeper knowledge of the metabolic impairment determinants is compelling to identify the pathological mechanisms promoting the onset of prediabetes and CRC. In this scenario, this review aims to provide a comprehensive overview on the metabolic alterations of prediabetes and CRC as well as an overview of recent preventive and therapeutic approaches for both diseases, focusing on the role of the metabolic state as a pivotal contributor to consider for the development of future preventive and therapeutic strategies.

Use of weight loss medications in relation with prostate, colorectal and male breast cancers among older men: SEER-Medicare 2007-2015

BACKGROUND

The association of weight loss medications with prostate (PCa), colorectal (CRC) or male breast cancers, including assessment of these cancers combined (HRCs, hormone-associated cancers) remain poorly understood. Testosterone replacement therapy (TTh) is reported to be inversely associated with obesity, PCa and CRC, but it is unclear whether TTh modifies the association of weight loss medications with HRCs.

METHODS

In 49,038 men (≥ 65 years) of SEER-Medicare, we identified 15,471 men diagnosed with PCa, 4836 with CRC, and 141 with male breast cancers. Pre-diagnostic prescription of weight loss medications and TTh was ascertained for this analysis. Weighted multivariable-adjusted conditional logistic and Cox proportional hazards (mortality) models were conducted.

RESULTS

We found an inverse association between use of weight loss medications and incident PCa (OR 0.59, 95% CI 0.57-0.62), CRC (OR 0.86, 95% CI 0.80-0.92), and HRCs (OR 0.65, 95% CI 0.62-0.68). Similar associations were observed for advanced stage at diagnosis of PCa and CRC. Effects of weight loss medications on PCa and HRC remained significant irrespective of the use of TTh but were only suggestive with CRC with positive TTh use. No associations were observed with male breast cancer and HRCs mortality.

CONCLUSION

Pre-diagnostic use of weight loss medications reduced the incidence of PCa, CRC, and HRCs. These associations persisted in the same direction irrespective of the history of TTh use. Future studies are needed to confirm these findings and to identify underlying biological mechanisms of weight loss medications and TTh on the risk of cancer.

Marked paper: Type 2 diabetes mellitus indicates increased postoperative complications and poor prognosis in colorectal cancer patients receiving curative surgery

Purpose

This study aimed to evaluate the impact of type 2 diabetes mellitus (T2DM) on the short-term outcomes and long-term survival of patients with colorectal cancer (CRC) who underwent curative resection.

Methods

This study retrospectively included 136 patients (T2DM group) with resectable CRC and T2DM from Jan 2013 to Dec 2017. Propensity score-matched control group consisting of 136 patients (non-T2DM group) were selected from 1143 CRC patients without T2DM. The short-term outcomes and prognosis were compared between the T2DM and non-T2DM group.

Results

A total of 272 patients (136 patients for each group) were included in this study. Patients in T2DM group had higher body mass index (BMI), higher proportion of hypertension and cerebrovascular diseases (P<0.05). T2DM group had more overall complications (P=0.001), more major complications (P=0.003) and higher risk of reoperation (P=0.007) when compared with non-T2DM patients. T2DM patients had longer hospitalization time than non-T2DM (20.7 ± 10.2 vs. 17.5 ± 6.2, P=0.002). As for the prognosis, T2DM patients had worse 5-year overall survival (OS) (P=0.024) and 5-year disease-free survival (DFS) (P=0.019) in all stage. Moreover, T2DM and TNM stage were the independent predictors of OS and DFS for CRC patients.

Conclusions

T2DM increases overall complications and major complications, and prolongs the hospitalization time after CRC surgery. In addition, T2DM indicates the poor prognosis of CRC patients. A prospective study with large sample size is required to confirm our findings.

Phosphoproteomic analysis of metformin signaling in colorectal cancer cells elucidates mechanism of action and potential therapeutic opportunities

BACKGROUND

The biguanide drug metformin is a safe and widely prescribed drug for type 2 diabetes. Interestingly, hundreds of clinical trials have been set to evaluate the potential role of metformin in the prevention and treatment of cancer including colorectal cancer (CRC). However, the "metformin signaling" remains controversial.

AIMS AND METHODS

To interrogate cell signaling induced by metformin in CRC and explore the druggability of the metformin-rewired phosphorylation network, we performed integrative analysis of phosphoproteomics, bioinformatics, and cell proliferation assays on a panel of 12 molecularly heterogeneous CRC cell lines. Using the high-resolute data-independent analysis mass spectrometry (DIA-MS), we monitored a total of 10,142 proteins and 56,080 phosphosites (P-sites) in CRC cells upon a short- and a long-term metformin treatment.

RESULTS AND CONCLUSIONS

We found that metformin tended to primarily remodel cell signaling in the long-term and only minimally regulated the total proteome expression levels. Strikingly, the phosphorylation signaling response to metformin was highly heterogeneous in the CRC panel, based on a network analysis inferring kinase/phosphatase activities and cell signaling reconstruction. A "MetScore" was determined to assign the metformin relevance of each P-site, revealing new and robust phosphorylation nodes and pathways in metformin signaling. Finally, we leveraged the metformin P-site signature to identify pharmacodynamic interactions and confirmed a number of candidate metformin-interacting drugs, including navitoclax, a BCL-2/BCL-xL inhibitor. Together, we provide a comprehensive phosphoproteomic resource to explore the metformin-induced cell signaling for potential cancer therapeutics. This resource can be accessed at https://yslproteomics.shinyapps.io/Metformin/.

Effects of diabetes type 2 and metformin treatment in Swedish patients with colorectal cancer

The association between type 2 diabetes mellitus (DM) and colorectal cancer (CRC) has been thoroughly investigated and reports have demonstrated that the risk of CRC is increased in DM patients. The association between DM and the survival of patients with CRC is controversial. Evidence suggests that metformin with its anti-inflammatory effects is a protective factor against the development of CRC among DM patients and that metformin therapy is associated with a better prognosis in patients with DM. In our cohort, we did not find any associations between the presence of DM or metformin and cancer specific survival or any relation to plasma levels of a panel of 40 inflammatory factors and irisin. On the other hand, we identified that the insulin-like growth factor binding protein 7 single nucleotide polymorphism rs2041437 was associated with DM in CRC patients. The dominance of the T bearing genotypes in patients with DM was statistically significant (P = 0.038), with an odds ratio of 1.66 (95% confidence interval: 1.03-2.69).

Metformin: A Narrative Review of Its Potential Benefits for Cardiovascular Disease, Cancer and Dementia

The biguanide metformin has been used as first-line therapy in type 2 diabetes mellitus (T2DM) treatment for several decades. In addition to its glucose-lowering properties and its prevention of weight gain, the landmark UK Prospective Diabetes Study (UKPDS) demonstrated cardioprotective properties in obese T2DM patients. Coupled with a favorable side effect profile and low cost, metformin has become the cornerstone in the treatment of T2DM worldwide. In addition, metformin is increasingly being investigated for its potential anticancer and neuroprotective properties both in T2DM patients and non-diabetic individuals. In the meantime, new drugs with powerful cardioprotective properties have been introduced and compete with metformin for its place in the treatment of T2DM. In this review we will discuss actual insights in the various working mechanisms of metformin and the evidence for its beneficial effects on (the prevention of) cardiovascular disease, cancer and dementia. In addition to observational evidence, emphasis is placed on randomized trials and recent meta-analyses to obtain an up-to-date overview of the use of metformin in clinical practice.