Association between type 2 diabetes, curative treatment and survival in men with intermediate- and high-risk localized prostate cancer

Prostate Cancer-specific Survival After Radical Prostatectomy Is Improved Among Metformin Users but Not Among Other Antidiabetic Drug Users

Background

Metformin has been linked to improved survival among diabetic prostate cancer (PCa) patients, while hyperinsulinemia and insulin usage has been related to worse prognosis.

Objective

To evaluate the association of metformin and other antidiabetic drugs with PCa death and androgen deprivation therapy (ADT).

Design, setting, and participants

The study cohort included 14 424 men who underwent radical prostatectomy in Finland during 1995–2013. Cases were identified, and clinical data were collected from patient files and national registries using personal identification numbers.

Intervention

Information on the use of each antidiabetic drug during 1995–2014 was collected from prescription registry of the Social Insurance Institution of Finland.

Outcome measurements and statistical analysis

The risks of PCa death and initiation of ADT were analyzed by antidiabetic drug use with the Cox regression method. Each antidiabetic drug group was analyzed separately to model simultaneous usage. Pre- and postdiagnostic uses were analyzed separately.

Results and limitations

Prediagnostic use of antidiabetic drugs in general had no association with the risk of PCa death. Prediagnostic use of metformin was related to a reduced risk of ADT initiation (hazard ratio [HR] 0.75, 95% confidence interval [CI] 0.59–0.96), while high-dose insulin users had an increased risk. Overall, antidiabetic drug use after PCa diagnosis was associated with an elevated risk of PCa death. Only postdiagnostic metformin use was associated with reduced risks of PCa death (HR 0.47, 95% CI 0.30–0.76) and ADT initiation compared with nonusers. Study limitations are missing information on glycemic control, smoking, living or exercise habits, prostate-specific antigen, and Gleason score.

Conclusions

Among surgically treated PCa patients, use of metformin was associated with improved disease-specific survival, while insulin and insulin secretagogues were associated with poor survival. Metformin might be a favorable diabetes treatment among men with PCa.

Patient summary

In this Finnish nationwide study, we found that the risks of prostate cancer death and cancer progression are lowered among metformin users, but not among other antidiabetic drug users. Metformin might be a favorable treatment choice for diabetes in men with prostate cancer.

The Value of Real-World Data in Understanding Prostate Cancer Risk and Improving Clinical Care: Examples from Swedish Registries

Simple Summary

Real-world data (RWD), i.e., data reflecting normal clinical practice collected outside the constraints of randomised controlled trials, provide important insights into our understanding of prostate cancer and its management. Clinical cancer registries are an important source of RWD. Depending on their scope and the potential linkage to other data sources, registry-based data can be utilised to address a variety of questions including risk factors, healthcare utilisation, treatment effectiveness, adverse effects, disparities in healthcare access, quality of care and healthcare economics. This review describes the various registry-based RWD sources for prostate cancer research in Sweden (namely the National Prostate Cancer Register, the Prostate Cancer data Base Sweden (PCBaSe) and the Patient-overview Prostate Cancer) and documents their utility for better understanding prostate cancer aetiology and improving clinical care.

Abstract

Real-world data (RWD), that is, data from sources other than controlled clinical trials, play an increasingly important role in medical research. The development of quality clinical registers, increasing access to administrative data sources, growing computing power and data linkage capacities have contributed to greater availability of RWD. Evidence derived from RWD increases our understanding of prostate cancer (PCa) aetiology, natural history and effective management. While randomised controlled trials offer the best level of evidence for establishing the efficacy of medical interventions and making causal inferences, studies using RWD offer complementary evidence about the effectiveness, long-term outcomes and safety of interventions in real-world settings. RWD provide the only means of addressing questions about risk factors and exposures that cannot be “controlled”, or when assessing rare outcomes. This review provides examples of the value of RWD for generating evidence about PCa, focusing on studies using data from a quality clinical register, namely the National Prostate Cancer Register (NPCR) Sweden, with longitudinal data on advanced PCa in Patient-overview Prostate Cancer (PPC) and data linkages to other sources in Prostate Cancer data Base Sweden (PCBaSe).

Heterogeneity in risk of prostate cancer: A Swedish population-based cohort study of competing risks and Type 2 diabetes mellitus

Most previous studies of prostate cancer have not taken into account that men in the studied populations are also at risk of competing event, and that these men may have different susceptibility to prostate cancer risk. The aim of our study was to investigate heterogeneity in risk of prostate cancer, using a recently developed latent class regression method for competing risks. We further aimed to elucidate the association between Type 2 diabetes mellitus (T2DM) and prostate cancer risk, and to compare the results with conventional methods for survival analysis. We analysed the risk of prostate cancer in 126,482 men from the comparison cohort of the Prostate Cancer Data base Sweden (PCBaSe) 3.0. During a mean follow-up of 6 years 6,036 men were diagnosed with prostate cancer and 22,393 men died. We detected heterogeneity in risk of prostate cancer with two distinct latent classes in the study population. The smaller class included 9% of the study population in which men had a higher risk of prostate cancer and the risk was stronger associated with class membership than any of the covariates included in the study. Moreover, we found no association between T2DM and risk of prostate cancer after removal of the effect of informative censoring due to competing risks. The recently developed latent class for competing risks method could be used to provide new insights in precision medicine with the target to classify individuals regarding different susceptibility to a particular disease, reaction to a risk factor or response to treatment.