The protective effect of diabetes mellitus against prostate cancer: role of sex hormones

Metabolic syndrome biomarkers and prostate cancer risk in the UK Biobank

We investigated the association between metabolic syndrome (MetS) and its components and risk of prostate cancer (PCa) in a cohort of men enrolled in the UK Biobank. Our study cohort included 220 622 PCa-free men with baseline measurements of triglycerides (TGs), HDL-cholesterol (HDL), glycated hemoglobin (HbA1c), blood pressure (BP), and waist circumference (WC). Multivariable Cox proportional hazards regression was used to analyze associations with PCa for: individual metabolic components (TG, HDL, HbA1c, BP, WC), combinations of two and three components, and MetS overall (three or more components). We conducted mediation analyses to examine potential hormonal and inflammatory pathways (total testosterone [TT], C-reactive protein [CRP], insulin-like growth factor 1 [IGF-1]) through which MetS components may influence PCa risk. A total of 5409 men in the study developed PCa during a median follow-up of 6.9 years. We found no significant association between MetS and PCa risk (hazard ratio [HR] = 0.99, 95% confidence interval [CI] = 0.92-1.06). No associations were found with PCa risk and individual measurements of TG, HDL, BP, or WC. However, an inverse association was observed with elevated HbA1c (≥42 mmol/mol) (HR = 0.89, 95% CI = 0.79-0.98). Consistent inverse associations were observed between HbA1c and risk of PCa. Mediation analysis revealed TT, CRP, and IGF-1 as potential mediating factors for this association contributing 10.2%, 7.1%, and 7.9% to the total effect, respectively. Overall MetS had no association with PCa risk. However, a consistent inverse association with PCa risk was found for HbA1c. This association may be explained in part through hormonal and inflammatory pathways.

The association of diabetes with risk of prostate cancer defined by clinical and molecular features

BACKGROUND

To prospectively examine the association between diabetes and risk of prostate cancer defined by clinical and molecular features.

METHODS

A total of 49,392 men from the Health Professionals Follow-up Study (HPFS) were followed from 1986 to 2014. Data on self-reported diabetes were collected at baseline and updated biennially. Clinical features of prostate cancer included localised, advanced, lethal, low-grade, intermediate-grade, and high-grade. Molecular features included TMPRSS2: ERG and PTEN subtypes. Cox proportional hazards regression models were used to evaluate the association between diabetes and incidence of subtype-specific prostate cancer.

RESULTS

During 28 years of follow-up, we documented 6733 incident prostate cancer cases. Relative to men free from diabetes, men with diabetes had lower risks of total (HR: 0.82, 95% CI: 0.75-0.90), localised (HR: 0.82, 95% CI: 0.74-0.92), low-and intermediate-grade prostate cancer (HR: 0.77, 95% CI: 0.66-0.90; HR: 0.77, 95% CI: 0.65-0.91, respectively). For molecular subtypes, the HRs for ERG-negative and ERG-positive cases were 0.63 (0.42-0.95) and 0.72 (0.46-1.12); and for PTEN-intact and PTEN-loss cases were 0.69 (0.48-0.98) and 0.52 (0.19-1.41), respectively.

CONCLUSION

Besides providing advanced evidence for the inverse association between diabetes and prostate cancer, this study is the first to report associations between diabetes and ERG/PTEN defined prostate cancers.

Metformin for lung cancer prevention and improved survival: a novel approach

Diabetes mellitus has been associated with increased risk for the development of many types of cancer. Metformin, an oral medication and first-line treatment for type 2 diabetes mellitus, has been suggested to reduce cancer risk and mortality in various types of cancer. This study focuses on assessing metformin association with lung cancer as reported in the literature. Recent studies and reviews investigating metformin effects on lung cancer incidence and patient survival are critically and systematically discussed.

Poorly controlled diabetes increases the risk of metastases and castration-resistant prostate cancer in men undergoing radical prostatectomy: Results from the SEARCH database

BACKGROUND

Although diabetes is inversely related to prostate cancer (PC) risk, to the authors' knowledge the impact of glycemic control on PC progression is unknown. In the current study, the authors tested the association between hemoglobin A1c (HbA1c) and long-term PC outcomes among diabetic men undergoing radical prostatectomy (RP).

METHODS

The authors retrospectively reviewed data regarding men undergoing RP from 2000 to 2017 at 8 Veterans Affairs hospitals. Diabetic patients were identified using International Classification of Diseases, Ninth Revision (ICD-9) codes (250.x) or by an HbA1c value >6.5% at any time before RP. Cox models tested the association between HbA1c and biochemical disease recurrence (BCR), castration-resistant PC (CRPC), metastases, PC-specific mortality, and all-cause mortality. The model for BCR was adjusted for multiple variables. Due to limited events, models for long-term outcomes were adjusted for biopsy grade and prostate-specific antigen only.

RESULTS

A total of 1409 men comprised the study population. Of these, 699 patients (50%) had an HbA1c value <6.5%, 631 (45%) had an HbA1c value of 6.5% to 7.9%, and 79 (6%) had an HbA1c value ≥8.0%. Men with an HbA1c value ≥8.0% were younger (P < .001) and more likely to be black (P = .013). The median follow-up after RP was 6.8 years (interquartile range, 3.7-10.6 years). On multivariable analysis, HbA1c was not found to be associated with BCR. However, a higher HbA1c value was associated with metastasis (hazard ratio [HR], 1.21; 95% CI, 1.02-1.44 [P = .031]) and CRPC (HR, 1.27; 95% CI, 1.03-1.56 [P = .023]). Although not statistically significant, there were trends between higher HbA1c and risk of PC-specific mortality (HR, 1.24; 95% CI, 0.99-1.56 [P = .067]) and all-cause mortality (HR, 1.09; 95% CI, 0.99-1.19 [P = .058]).

CONCLUSIONS

Among diabetic men undergoing RP, a higher HbA1c value was associated with metastases and CRPC. If validated in larger studies with longer follow-up, future research should test whether better glycemic control improves long-term PC outcomes.

Difference in prostate cancer incidence around sixty years: effects of age and metabolic diseases

We examined the risk of prostate cancer in the Korean population stratified on the basis of age group and risk based on metabolic diseases, using National Health Insurance System (NHIS) data. Of the 51,827,813 people from the NHIS data in 2015, 10,879,591 men without prostate cancer who underwent a health examination were analyzed. The risk of prostate cancer was analyzed with stratification by age. Multivariate-adjusted Cox regression analysis was conducted to examine the association between prostate cancer and metabolic diseases by age groups. The risk of prostate cancer increased continuously with age and 59 years may be a point of inflection. The hazard ratio (HR) of prostate cancer development rose sharply as that age point passed. The population with metabolic diseases was more likely to develop prostate cancer than the population without any of these components. In addition, the incidence rate ratio (IRR) decreased from the youngest age group to the age group comprising 55-59 year olds. Beyond this age group, there was a plateau. The relative risk for prostate cancer associated with metabolic diseases also showed divergent associations with age. The risk of prostate cancer increased continuously with age and the peak Youden index was at 59 years. The relative risk for prostate cancer according to metabolic diseases also showed divergent associations beyond 59 years of age. Therefore, setting the age threshold at 59 years would improve the present clinical risk stratification for prostate cancer in Korea.

A cross-sectional study on the associations of insulin resistance with sex hormone, abnormal lipid metabolism in T2DM and IGT patients

Type 2 diabetes mellitus (T2DM) is a long-term metabolic disorder. It is characterized by hyperglycemia, insulin resistance (IR), and relative impairment in insulin secretion. IR plays a major role in the pathogenesis of T2DM. Many previous studies have investigated the relationship between estrogen, androgen, and obesity, but few focused on the relationship between sex hormones, abnormal lipid metabolism, and IR. The goal for the present study was to identify the association of IR with sex hormone, abnormal lipid metabolism in type 2 diabetes, and impaired glucose tolerance (IGT) patients.In total 13,400 participants were analyzed based on the results of the glucose tolerance test. Using a cross-sectional study, we showed the relationship between IR and the level of sex hormones among 3 different glucose tolerance states: normal control people, IGT, and T2DM patients. We also analyzed the relationship between IR and abnormal lipid metabolism.Significantly, luteinizing, progesterone, estradiol, prolactin, and follicle-stimulating hormone levels decreased in T2DM and IGT patients compared with those in normal control people. The association between IR and lipid metabolism disorders in T2DM and IGT patients was also observed.Our clinical findings may offer new insights into understanding the mechanism of metabolic disorders and in new therapeutic methods for the treatment of the prevalence of type 2 diabetes.

The association of diabetes and obesity with prostate cancer aggressiveness among Black Americans and White Americans in a population-based study

PURPOSE

Few studies have investigated the role of race in the association of diabetes and obesity with prostate cancer aggressiveness. Here we evaluate the independent association between diabetes and obesity with prostate cancer aggressiveness in White Americans and Black Americans.

METHODS

Our cross-sectional, case-only study consisted of 1,058 White Americans and 991 Black Americans from the North Carolina-Louisiana Prostate Cancer (PCaP) project. Diabetes status was determined by self-report. Obesity was determined using body mass index and calculated based on anthropometric measurements. High aggressive prostate cancer was defined as Gleason sum ≥8, or prostate-specific antigen >20 ng/ml, or Gleason sum = 7 and clinical stage cT3-cT4. The association between diabetes and obesity with high aggressive prostate cancer at diagnosis was evaluated using multivariable logistic regression and adjusted for potential confounders.

RESULTS

Diabetes was not associated with high aggressive prostate cancer in the overall sample (OR 1.04; 95% CI 0.79, 1.37), White Americans (OR 1.00; 95% CI 0.65, 1.57) or Black Americans (OR 1.07; 95% CI 0.75, 1.53). Obesity, independent of diabetes, was positively associated with high aggressive prostate cancer in White Americans (OR 1.98; 95% CI 1.14, 3.43), but not in the overall sample (OR 1.37; 95% CI 0.99, 1.92) or Black Americans (OR 1.09; 95% CI 0.71, 1.67).

CONCLUSIONS

Diabetes was not associated with prostate cancer aggressiveness, overall, or in either race group. Obesity, independent of diabetes, was associated with high aggressive prostate cancer only in White Americans.

Diabetes and mortality in patients with prostate cancer: a meta-analysis

BACKGROUND

There are conflicting results as to the association between pre-existing diabetes and the risk of mortality in patients with prostate cancer. The purpose of this study is to estimate the influence of pre-existing diabetes on prostate cancer-specific mortality and all-cause mortality.

METHODS

We searched PubMed and Embase to identify studies that investigated the association between pre-existing diabetes and risk of death among men with prostate cancer. Pooled risk estimates and 95 % confidence intervals were calculated using fixed-effects models or random-effects models. Heterogeneity tests were conducted between studies. Publication bias was analyzed by using the Egger's test, Begg's test, and the trim and fill method.

RESULTS

Of the 733 articles identified, 17 cohort studies that had 274,677 male patients were included in this meta-analysis. Pre-existing diabetes was associated with a 29 % increase in prostate cancer-specific mortality [relative risk (RR) 1.29, 95 % CI 1.22-1.38, I(2) = 66.68 %], and with a 37 % increase in all-cause mortality (RR 1.37, 95 % CI 1.29-1.45, p < 0.01, I(2) = 90.26 %). Additionally, in a subgroup analysis that was a type specific analysis focusing on type 2 diabetes and was conducted only with three cohort studies, pre-existing type 2 diabetes was associated with all-cause mortality (RR 2.01, 95 % CI 1.37-2.96, I(2) = 95.55 %) and no significant association with prostate cancer-specific mortality was detected (RR 1.17, 95 % CI 0.96-1.42, I(2) = 75.59 %). There was significant heterogeneity between studies and no publication bias was found.

CONCLUSIONS

This meta-analysis suggests diabetes may result in a worse prognosis for men with prostate cancer. Considering heterogeneity between studies, additional studies should be conducted to confirm these findings, and to allow generalization regarding the influence that each type of diabetes has on prostate cancer mortality.

Studying the effect of type 2 diabetes mellitus on prostate-related parameters: A prospective single institutional study

Background

To examine the effects of type 2 diabetes mellitus (DM) on the variables associated with prostatic growth including serum prostate-specific antigen (PSA), serum testosterone, and prostate volume, and to correlate these variables with the duration of diabetes treatment.

Methods

Our study was conducted over 3 months recruiting 501 men aged ≥ 55 years; of whom 207 had type 2 DM. Exclusion criteria were active urinary tract infection, suspicious rectal examination, urologic cancer, end-organ damage, and recent urological manipulations. Serum PSA and serum testosterone were measured. Prostate volume was determined by abdominal ultrasonography using an ellipsoid formula.

Results

The mean patient age was 60.21 ± 5.95 years. The mean PSA, testosterone, and prostate volume for diabetic men were 2.3 ng/mL, 3 ng/mL, and 56 g, respectively. The corresponding values for nondiabetic men were 3.5 ng/mL, 4 ng/mL, and 51 g, respectively (P = 0.001, P = 0.001, P = 0.03, respectively). The mean PSA density was 0.049 ± 0.043 ng/mL/cm³ in diabetics versus 0.080 ± 0.056 ng/mL/cm³ in non-diabetics (P < 0.001).

Conclusion

Type 2 DM is significantly associated with lower serum PSA and testosterone, and larger prostate volume.

Diabetes mellitus and the risk of prostate cancer: an update and cumulative meta-analysis

INTRODUCTION

To provide further insight into the association between type 2 diabetes mellitus (T2DM) and the pathophysiology of prostate cancer, we conducted an updated, detailed meta-analysis of 56 published case-control and cohort studies.

METHODS

MEDLINE and EMBASE were used to identify the literature published in April 2012 related to both diabetes mellitus and prostate cancer. A sensitivity analysis was performed, and potential confounding effects were investigated using a stratified meta-analysis. A cumulative meta-analysis was also carried out to evaluate the cumulative effect estimate over time.

RESULTS

A total of 24 case-control and 32 cohort studies with information on a total of ~8,000,000 subjects and ~140,000 individuals with prostatic cancer showed published estimates of the association between diabetes and prostate cancer malignancy. The pooled effect estimate revealed a relative risk (RR) of 0.88 (95% CI, 0.82-0.93). Interestingly, there was an increased trend for Asians (RR = 1.72, n = 7) but not Americans (RR = 0.82, n = 28) and Europeans (RR = 0.86, n = 21) regarding the association between diabetes mellitus and prostate cancer. The sensitivity analysis, excluding any one study, did not significantly change the pooled RR. The range for the pooled RR when one study was omitted was 0.84-0.89.

DISCUSSION

The findings of our meta-analysis provide strong evidence of an inverse association between diabetes and prostate cancer.

CONCLUSIONS

Further research should focus on limitations in the current literature and re-assess the relationship between diabetes and prostate cancer by analyzing the two different diabetes mellitus types separately.

CARING (CAncer Risk and INsulin analoGues): the association of diabetes mellitus and cancer risk with focus on possible determinants - a systematic review and a meta-analysis

Background:

Patients suffering from diabetes mellitus (DM) may experience an increased risk of cancer; however, it is not certain whether this effect is due to diabetes per se.

Objective:

To examine the association between DM and cancers by a systematic review and meta-analysis according to the PRISMA guidelines.

Data Sources:

The systematic literature search includes Medline at PubMed, Embase, Cinahl, Bibliotek.dk, Cochrane library, Web of Science and SveMed+ with the search terms: “Diabetes mellitus”, “Neoplasms”, and “Risk of cancer”.

Study Eligibility Criteria:

The included studies compared the risk of cancer in diabetic patients versus non-diabetic patients. All types of observational study designs were included.

Results:

Diabetes patients were at a substantially increased risk of liver (RR=2.1), and pancreas (RR=2.2) cancer. Modestly elevated significant risks were also found for ovary (RR=1.2), breast (RR=1.1), cervix (RR=1.3), endometrial (RR=1.4), several digestive tract (RR=1.1-1.5), kidney (RR=1.4), and bladder cancer (RR=1.1). The findings were similar for men and women, and unrelated to study design. Meta-regression analyses showed limited effect modification of body mass index, and possible effect modification of age, gender, with some influence of study characteristics (population source, cancer- and diabetes ascertainment).

Limitations:

Publication bias seemed to be present. Only published data were used in the analyses.

Conclusions:

The systematic review and meta-analysis confirm the previous results of increased cancer risk in diabetes and extend this to additional cancer sites. Physicians in contact with patients with diabetes should be aware that diabetes patients are at an increased risk of cancer.

Type 2 diabetes: a protective factor for prostate cancer? An overview of proposed mechanisms

Diabetes mellitus and prostate cancer are 2 of the most important public health concerns, especially in the elderly population. Although diabetes has been recognized as a potent risk factor for many types of cancers, there is a large amount of evidence that shows that it has a protective role against prostate cancer. The underlying cause of this protective role is not fully understood, however, some mechanisms have been proposed in this area. In the present study we have reviewed these mechanisms and some new mechanisms are also proposed.

Prostate cancer risk in pre-diabetic men: a matched cohort study

BACKGROUND

Diagnosis and duration of type 2 diabetes mellitus (DM) appear to be associated with decreased prostate cancer risk. Limitations of previous studies include methods of subject selection and accurate definition of DM diagnosis. We examined the temporal relationship between DM and prostate cancer risk exploring the period of greatest risk starting from the prediabetic to the post-diabetic period using clinical and administrative data to accurately define the date of DM diagnosis.

METHODS

We identified 5,813 men who developed DM between January 1, 1995 and December 31, 2009 (reference date, date of DM onset or matched date for non-diabetic cohort) and 28,019 non-diabetic men matched by age, smoking history, residence, and reference date. Prostate cancer incidence before and after the reference date was assessed using Cox regression modeling adjusted for matching variables, body mass index, insurance status, and comorbidities. Primary outcomes included hazard ratio (HR) and number needed to be exposed to DM for one additional person to be harmed (NNEH) or benefit (NNEB) with respect to prostate cancer risk.

RESULTS

After full adjustment, the HR for prostate cancer before DM diagnosis was 0.96 (95% CI 0.85-1.08; P=0.4752), and the NNEB was 974 at DM diagnosis. After the reference date, the fully-adjusted HR for prostate cancer in diabetic men was 0.84 (95% CI 0.72-0.97, P=0.0167), and the NNEB 3 years after DM onset was 425. The NNEB continued to decrease over time, reaching 63 at 15 years after DM onset, suggesting an increasing protective effect of DM on prostate cancer risk over time. No significant difference between the diabetic and non-diabetic cohort was found prior to reference date.

CONCLUSION

Prostate cancer risk is not reduced in pre-diabetic men but decreases after DM diagnosis and the protective effect of DM onset on prostate cancer risk increases with DM duration.

Metabolic dysregulation of the insulin-glucose axis and risk of obesity-related cancers in the Framingham heart study-offspring cohort (1971-2008)

BACKGROUND

Obesity-related dysregulation of the insulin-glucose axis is hypothesized in carcinogenesis. We studied impaired fasting glucose (IFG) and other markers of insulin-glucose metabolism in the Framingham Heart Study-Offspring Cohort, which uniquely tracks these markers and cancer >37 years.

METHODS

Participants were recruited between 1971 and 1975 and followed until 2008 (n = 4,615; mean age 66.8 years in 2008). Serum glucose, insulin, and hemoglobin A1c were determined from fasting blood in quart-annual exams. Lifestyle and demographic information was self-reported. HRs and 95% confidence intervals (CI) of cancer risk were computed using time-dependent survival analysis (SASv9.3), while accounting for temporal changes for relevant variables.

RESULTS

We identified 787 obesity-related cancers, including 136 colorectal, 217 breast, and 219 prostate cancers. Absence versus presence of IFG 10 to 20 years and 20+ years before the event or last follow-up was associated with 44% (95% CI, 1.15-1.79) and 57% (95% CI, 1.17-2.11) increased risk of obesity-related cancers, respectively. When time-dependent variables were used, after adjusting for age, sex, smoking, alcohol, and body mass index, IFG was associated with a 27% increased risk of obesity-related cancer (HR = 1.27; CI, 1.1-1.5). Associations were stronger in smokers (HR = 1.41; CI, 1.13-1.76). Increased risk was noted among persons with higher insulin (HR = 1.47; CI, 1.15-1.88) and hemoglobin A1c (HR = 1.54; CI, 1.13-2.10) for the highest (≥ 5.73%) versus lowest (≤ 5.25%) category. A >2-fold increase in colorectal cancer risk was observed for all blood biomarkers of insulin-glucose metabolism, particularly with earlier IFG exposure. Nonsignificant increased risk of breast and prostate cancer was observed for blood biomarkers.

CONCLUSIONS

Earlier IFG exposure (>10 years before) increased obesity-related cancer risk, particularly for colorectal cancer.

IMPACT

Our study explicitly recognizes the importance of prolonged IFG exposure in identifying links between glucose dysregulation and obesity-related cancers.

Serum calcium concentration and prostate cancer risk: a multicenter study

This study sought to further evaluate the possible effects of serum calcium level on prostate cancer (PC) risk, with considering the age, body mass index (BMI), and sex steroid hormones. Using data from a prospective multicenter study, serum calcium concentration, as well as thorough demographic and medical characteristics, were determined in 194 cases with newly diagnosed, clinicopathologically confirmed PC and 317 controls, without any malignant disease, admitted to the same network of hospitals. Serum total and ionized calcium levels were categorized into tertiles. Multivariate logistic regression model was used to estimate odds ratios (OR) and corresponding 95% confidence intervals (CI) after adjustment for major potential confounders, including age, BMI, smoking, alcohol, education, occupation, marital status, family history of PC, and sex hormones level. The mean serum calcium level (±SD) in case and control groups was 9.22 (±0.46) mg/dl and 9.48 (±0.51) mg/dl, respectively (P < 0.001). After adjustment for mentioned confounders, a significant trend of decreasing risk was found for serum total calcium concentration (OR = 0.27, 95% CI = 0.12-0.59, comparing the highest with the lowest tertile) and ionized calcium (OR = 0.25, 95% CI = 0.10-0.58). An increase of 1 mg/dl in serum calcium level was associated with a significant decrease in PC risk (OR = 0.52; 95% CI = 0.34-0.76). Our findings reveal the inverse association between serum total and ionized concentrations and PC risk, which supports the hypothesis that calcium may protect against PC. Furthermore, no evidence was found regarding age, BMI, and sex steroid hormones to modify the association between serum calcium and PC risk.

Why are diabetics at reduced risk for prostate cancer? A review of the epidemiologic evidence

A large body of epidemiologic evidence provides strong support for the notion that type-2 diabetics are at decreased risk for prostate cancer. In this review article, we summarize the epidemiologic literature that explores the role of diabetes mellitus and related biomarkers in prostate cancer risk and detection, in order to create a better understanding of the potential mechanisms that underlie this inverse association. The bulk of the data supporting this association comes from the USA, as evidence for this association is less consistent in many other regions of the world. The relationship between diabetes and prostate cancer is suspected to be causal due to evidence of decreasing prostate cancer risk with increasing diabetes duration and lack of evidence for any confounding of this association. Hypothesized mechanisms for decreased prostate cancer risk among diabetics include (1) decreased levels of hormones and other cancer-related growth factors among diabetics, (2) the impact of diabetes on detection-related factors, such as prostate size, circulating prostate-specific antigen (PSA), and health-care seeking behaviors, (3) protective effects of diabetes medications, and (4) a protective effect of diabetes-induced vascular damage in the prostate. The evidence for screening-related factors is compelling, as diabetics appear to have reduced PSA and lower levels of health-care seeking behavior compared with nondiabetics. Furthermore, the inverse association between diabetes and prostate cancer is much less apparent in populations that do not perform biopsies based on PSA levels and in studies restricted to biopsied individuals. The inverse association appears to be stronger for low-grade disease, as compared with high-grade (Gleason >7), which is consistent with the observation that among patients receiving biopsy or prostate cancer treatment, diabetics are more likely to have high-grade disease as compared to nondiabetics, potentially resulting in worse outcomes for diabetics. Epidemiological research has reveals a great deal regarding the relationship between diabetes and prostate cancer risk, but additional research is needed to further clarify the mechanisms underlying this inverse association.

The impact of diabetes mellitus on survival in men with clinically localized prostate cancer treated with permanent interstitial brachytherapy

PURPOSE

Patients with cancer of any origin with preexisting diabetes mellitus (DM) are at increased risk for all-cause mortality compared with those without DM. However, the influence of DM on biochemical progression-free survival (bPFS), cause-specific survival (CSS), and overall survival (OS) has not been clearly defined for men with clinically localized prostate cancer treated with brachytherapy.

MATERIALS AND METHODS

From April 1995 to May 2006, 1624 consecutive patients underwent brachytherapy with or without supplemental therapies. A prebrachytherapy diagnosis of diabetes was present in 199 patients (12.3%). Median follow-up was 7.8 years. Cause of death was determined for each deceased patient. Patients with metastatic prostate cancer or castrate-resistant disease without obvious metastases who died of any cause were classified as dead of prostate cancer. All other deaths were attributed to the immediate cause of death.

RESULTS

In patients without (n=1425) and with (n=199) DM, CSS was 97.2% versus 100% (P=0.168), bPFS was 95.6% versus 95.7% (P=0.960), and OS was 77.3% versus 56.0% at 12 years (P=0.003). In Cox regression analysis, OS in nondiabetic patients was most closely related to patient age, coronary artery disease, tobacco consumption, and androgen deprivation. In patients with diabetes, OS was related to patient age and coronary artery disease. In patients without diabetes, CSS was associated with Gleason score and clinical stage. No patient with diabetes died of prostate cancer. Patients with DM were more likely to die of cardiovascular disease (17.8% vs. 12.4%, P=0.007).

CONCLUSIONS

DM does not impact CSS or bPFS after brachytherapy. OS is significantly lower in patients with diabetes due to more deaths from cardiovascular disease.

Diabetes predicts metastasis after radical prostatectomy in obese men: results from the SEARCH database

OBJECTIVE

To examine the association between diabetes and metastasis risk after radical prostatectomy (RP) and to determine if race or obesity modifies this relationship.

PATIENTS AND METHODS

Patients comprised 2058 US veterans with prostate cancer (PCa) enrolled in the Shared Equal-Access Regional Cancer Hospital (SEARCH) database and treated with RP between 1988 and 2010. The association of diabetes with metastasis risk or secondary treatment rates was examined using Cox proportional hazards, adjusting for preoperative and, separately, clinical and postoperative findings. The effect modification by race (black vs white) and obesity (body mass index [BMI] ≥30 vs <30 kg/m(2) ) was tested via interaction terms.

RESULTS

Men with diabetes had higher BMIs and were more likely to be non-white (all P ≤ 0.001). On multivariable analysis, diabetes was not associated with metastasis risk (P ≥ 0.45), but, among men with diabetes, longer diabetes duration was associated with higher metastasis risk (P ≤ 0.035). When stratified by obesity, diabetes was linked with higher metastasis risk in obese but not in non-obese men (P-interaction ≤ 0.037), but there was no significant interaction with race (P-interaction ≥ 0.56). Diabetes also predicted more aggressive secondary treatment among obese men but less aggressive treatment among non-obese men (hazard ratio 1.39 vs 0.63, P-interaction = 0.006). Where applicable, results were similar for both pre- and postoperative models.

CONCLUSIONS

Diabetes was not associated with metastasis risk overall. Stratification by obesity yielded significant differences, with diabetes linked to a fourfold higher metastasis risk in obese men, despite predicting more aggressive secondary treatment. Longer diabetes duration was also associated with increased metastasis risk.

Diabetes mellitus and risk of prostate cancer: an updated meta-analysis based on 12 case-control and 25 cohort studies

The association between diabetes and risk of prostate cancer has been investigated widely. However, study results remain inconsistent and contradictory. Using a meta-analytic approach, the present study explore the relationship incorporating more recent studies and provide more powerful evidence without the limitations of any individual study. Relevant studies were identified by searching Pubmed and the Cochrane Central Register of Controlled Trials through May 18, 2012. The strength of the relationship between diabetes mellitus and risk of prostate cancer was assessed using relative risk (RR). Either a fixed effects or random effects model was used to calculate the pooled RRs. Stratification analyses and sensitivity analyses were conducted, and publication bias was assessed by Egger's test and Begg's test. Twelve case-control studies involving 9,767 cases and 19,790 controls, and 25 cohort studies involving 118,825 cases were included. The person-years of follow-up ranged from 29,963 to 6,264,890 among included cohort studies. Diabetes was not significantly associated with incidence of prostate cancer in our analysis of case-control studies only (RR = 0.846, 95 % CI [0.710, 1.009]) or that of cohort studies only (RR = 0.925, 95 % CI [0.811, 1.054]). However, through subgroup analyses, statistically significant associations between diabetes and prostate cancer were found when considering population-based studies only (RR = 0.719, 95 % CI [0.637, 0.812]), cohort studies conducted in the United States (RR = 0.789, 95 % CI [0.727, 0.857]), and studies with follow-up of more than 5 years. Compared to risk of prostate cancer among people without diabetes, diabetic patients using insulin treatment experienced reduced incidence of prostate cancer in both case-control and cohort studies. The results suggest that diabetes mellitus is associated with decreased incidence of prostate cancer, specifically in the population of the United States. In addition, the time since onset of diabetes was positively associated with decreasing incidence of prostate cancer. The present conclusions should be considered carefully, however, and confirmed with further studies.

Obesity, type 2 diabetes, and cancer: the insulin and IGF connection

Epidemiological studies suggest a positive association between obesity and type 2 diabetes mellitus (T2D) with the risk of cancer and cancer-related mortality. Insulin resistance, hyperinsulinemia, increased levels of IGF, elevated levels of steroid and peptide hormones, and inflammatory markers appear to play a role in the connection between these different diseases. Medications, such as metformin and exogenous insulin, used to treat T2D may affect the risk of cancer and cancer-related mortality. Newer therapies targeting the insulin and IGF1 systems are being developed for use in cancer therapy.

Diabetes mellitus is associated with short prostate-specific antigen doubling time after radical prostatectomy

OBJECTIVE

To investigate whether diabetes mellitus (DM) was associated with postoperative outcomes, including prostate-specific antigen doubling time, among men who underwent radical prostatectomy (RP) for clinically localized prostate cancer (PCa).

METHODS

Data of 661 patients who underwent radical prostatectomy for node-negative prostate cancer and were followed up for ≥3 years postoperatively at our institution were analyzed. Associations between diabetes mellitus at surgery and outcomes following radical prostatectomy, such as biochemical recurrence-free survival and prostate-specific antigen doubling time, were examined. Aggressive recurrence was defined as biochemical recurrence with prostate-specific antigen doubling time <9 months.

RESULTS

Of the 661 total subjects, DM (n = 67, 10.1 %) and non-DM group (n = 594, 89.9 %) showed no significant differences in various clinicopathologic parameters including age and PSA. DM group had lower postoperative biochemical recurrence-free survival than non-DM group, with observed difference approaching statistical significance (log-rank, p = 0.077). On multivariate analysis, DM at surgery was significantly associated with aggressive recurrence following RP (p = 0.048). Pathologic Gleason score (p = 0.008) and seminal vesicle invasion (p = 0.010) were also significantly associated with aggressive recurrence on multivariate analysis.

CONCLUSION

Our results show that pre-existing DM in men with PCa is associated with more aggressive recurrence, suggesting that DM may affect disease progression following RP. Further investigation would be needed to elucidate exact biologic interaction between DM and PCa and also assess causal relationships that potentially could be modified to improve long-term outcome in patients with the two diseases.

Diabetes and cancer I: risk, survival, and implications for screening

Type 2 diabetes mellitus (DM) and cancer are common diseases that are frequently diagnosed in the same individual. An association between the two conditions has long been postulated. Here, we review the epidemiological evidence for increased risk of cancer, decreased cancer survival, and decreased rates of cancer screening in diabetic patients. The risk for several cancers, including cancers of the pancreas, liver, colorectum, breast, urinary tract, and endometrium, is increased in patients with DM. In a pooled risk analysis weighting published meta-analytic relative risk (RR) for individual cancer by differences in their incidence rates, we found a population RR of 0.97 (95 % CI, 0.75-1.25) in men and 1.29 (95 % CI, 1.16-1.44) in women. All meta-analyses showed an increased relative risk for cancer in diabetic men, except studies of prostate cancer, in which a protective effect was observed. The relationship between diabetes and cancer appears to be complex, and at present, a clear temporal relationship between the two conditions cannot be defined. DM also impacts negatively on cancer-related survival outcomes and cancer screening rates. The overwhelming evidence for lower cancer screening rates, increased incidence of certain cancers, and poorer prognosis after cancer diagnosis in diabetic patients dictates a need for improved cancer care in diabetic individuals through improved screening measures, development of risk assessment tools, and consideration of cancer prevention strategies in diabetic patients. Part two of this review focuses on the biological and pharmacological mechanisms that may account for the association between DM and cancer.

The influence of antidiabetic medications on the development and progression of prostate cancer

BACKGROUND

The development of prostate tumors has been linked to co-morbid diabetes mellitus (DM) in several studies, potentially through the stimulation of insulin-like growth factor receptor (IGFR). This study evaluates the effect of anti-diabetic medication use on the development of high grade tumors and time to tumor progression compared to non-diabetics.

METHODS

This retrospective, nested case control study identified patients with prostate cancer (PCa) from the Kentucky Medicaid Database. Cases were diagnosed with PCa and DM and using at least one of the following antidiabetic medications; sulfonylureas, insulin, metformin or TZDs. Cases were further stratified on their insulin exposure resulting from therapy. Controls were those with PCa without DM or any anti-diabetic medications.

RESULTS

The use of metformin or TZDs trended toward decreased odds of high-grade tumors and decreased risk of progression, while sulfonylureas and high-dose insulin tended toward an increased odds of high-grade tumors and increase the risk of progression compared to non-diabetics.

CONCLUSIONS

Future studies should be conducted to further evaluate the effects of anti-diabetic medications on tumor grade and time to prostate cancer progression.

Impact of diabetes mellitus on the detection of prostate cancer via contemporary multi (≥ 12)-core prostate biopsy

BACKGROUND

Currently, controversy continues regarding the association between diabetes mellitus (DM) and prostate cancer (PCa). We investigated the impact of DM in PCa detection among men who underwent contemporary multi-core prostate biopsy.

METHODS

In this retrospective study, we reviewed records of 3,925 men who underwent multi (≥ 12)-core prostate biopsy at our institution. Biopsy outcomes were analyzed with respect to various variables, including DM, patient age, body mass index (BMI), prostate-specific antigen (PSA), digital rectal exam (DRE) finding, ultrasound finding, and prostate volume.

RESULTS

Among 3,925 subjects, 607 (15.5%) reported having DM at biopsy. Overall PCa was detected from biopsy in 1,387 (35.3%) patients, and high grade (biopsy Gleason score ≥ 7) PCa in 781 (19.9%). In multivariate analysis incorporating variables of patient age, BMI, PSA, DRE finding, ultrasound finding, and prostate volume, DM was observed to be significantly associated with higher odds of overall PCa detection via contemporary prostate biopsy (OR = 1.46, P = 0.019). When analyzed by tumor grade, DM was significantly associated with higher rate of high grade PCa detection from biopsy in multivariate analysis (OR = 1.54, P = 0.036) whereas DM and detection of low grade (biopsy Gleason score ≤ 6) PCa demonstrated no significant association (OR = 1.11, P = 0.558).

CONCLUSIONS

Our results showed DM was independently associated with the detection of high grade PCa via contemporary multi-core prostate biopsy. Further investigations would be needed to elucidate exact biologic basis of relationship between the two diseases.

Diabetes mellitus, race and the odds of high grade prostate cancer in men treated with radiation therapy

PURPOSE

Black men present more frequently with high grade prostate cancer and are more likely to have diabetes mellitus. We evaluated whether there is an independent association between diabetes mellitus and the risk of high grade prostate cancer in men diagnosed with prostate cancer and treated with radiation therapy.

MATERIALS AND METHODS

A polychotomous logistic regression analysis was performed to evaluate whether a diagnosis of diabetes mellitus was associated with the odds of Gleason score 7 or 8-10 prostate cancer in a cohort of 16,286 men, adjusting for black race, advancing age, prostate specific antigen and digital rectal examination findings.

RESULTS

Black men (adjusted OR 1.84, 95% CI 1.08-3.13, p = 0.024) and nonblack men (adjusted OR 1.59, 95% CI 1.33-1.89, p <0.001) with diabetes were more likely to have Gleason score 8-10 vs 6 or less prostate cancer than nondiabetic men. However, this was not true for Gleason score 7 vs 6 or less prostate cancer. Black race was significantly associated with Gleason score 7 vs 6 or less prostate cancer in men without and with diabetes (adjusted OR 1.38, 95% CI 1.17-1.63, p <0.001 and 1.61, 95% CI 1.17-2.21, p = 0.003, respectively). Black race was also associated with Gleason score 8-10 vs 6 or less prostate cancer in men without and with diabetes (adjusted OR 1.36, 95% CI 1.01-1.83, p = 0.04 and 1.58, 95% CI 0.98-2.53, p = 0.06, respectively).

CONCLUSIONS

In a cohort of men undergoing radiotherapy for prostate cancer the diagnosis of diabetes mellitus was significantly associated with an increased risk of being diagnosed with Gleason score 8-10 prostate cancer independent of black race.

The association of diabetes and positive prostate biopsy in a US veteran population

BACKGROUND

Several studies have shown a protective effect of diabetes mellitus (DM) on incidence of prostate cancer; however, the data are not consistent. Moreover, whether or not DM is associated with a positive result among patients referred for prostate biopsy due to abnormal PSA and/or abnormal digital rectal examination is not clear.

METHODS

A retrospective review of 3162 consecutive men who underwent prostate biopsy between January 2000 and July 2009 at the Atlanta Veterans Affairs Medical Center was performed. Men with positive and negative biopsies were compared for various demographic and clinical factors. The data were analyzed using logistic regression models with results expressed as adjusted odds ratios (ORs) with corresponding 95% confidence intervals (CI).

RESULTS

DM was associated with increased odds of positive biopsy in the overall cohort (OR 1.26, 95% CI: 1.01-1.55; P = 0.04). Subjects with DM had higher odds of more aggressive disease (Gleason ≥ 7) than those without the condition (OR 1.31, 95% CI: 0.98-1.74; P = 0.07). Race had no significant impact on these results.

CONCLUSIONS

In this large series of prostate biopsies, diabetes is associated with higher odds of positive biopsy and higher Gleason grade. More studies investigating the role of DM and its associated comorbidities in prostate carcinogenesis are needed.

Type 2 diabetes and cancer: what is the connection?

Epidemiological studies have demonstrated an association between type 2 diabetes and cancer. Type 2 diabetes is characterized by insulin resistance and hyperinsulinemia. Hyperinsulinemia may lead to cancer through insulin's effect on its cognate receptor and the insulin-like growth factor system. The effects of insulin and insulin-like growth factor I on cancer development and progression have been demonstrated in animal and human studies. Type 2 diabetes has been positively associated with cancers of the breast, colon, and pancreas. An inverse relationship has been observed between type 2 diabetes and prostate cancer, and this may be due to lower testosterone levels in men with type 2 diabetes. Medications used to treat type 2 diabetes may affect cancer cells directly or indirectly by affecting serum insulin levels. Hyperinsulinemia may be an important risk factor for cancer as well as a target for cancer therapy.

Diabetes and risk of prostate cancer: a study using the National Health Insurance

OBJECTIVE

The link between diabetes and prostate cancer is rarely studied in Asians.

RESEARCH DESIGN AND METHODS

The trend of age-standardized prostate cancer incidence in 1995-2006 in the Taiwanese general population was calculated. A random sample of 1,000,000 subjects covered by the National Health Insurance in 2005 was recruited. A total of 494,630 men for all ages and 204,741 men ≥ 40 years old and without prostate cancer at the beginning of 2003 were followed to the end of 2005. Cumulative incidence and risk ratio between diabetic and nondiabetic men were calculated. Logistic regression estimated the adjusted odds ratios for risk factors.

RESULTS

The trend of prostate cancer incidence increased significantly (P < 0.0001). The cumulative incidence markedly increased with age in either the diabetic or nondiabetic men. The respective risk ratio (95% CI) for all ages and age 40-64, 65-74, and ≥ 75 years was 5.83 (5.10-6.66), 2.09 (1.60-2.74), 1.35 (1.07-1.71), and 1.39 (1.12-1.71). In logistic regression for all ages or for age ≥ 40 years, age, diabetes, nephropathy, ischemic heart disease, dyslipidemia, living region, and occupation were significantly associated with increased risk, but medications including insulin and oral antidiabetic agents were not.

CONCLUSIONS

Prostate cancer incidence is increasing in Taiwan. A positive link between diabetes and prostate cancer is observed, which is more remarkable in the youngest age of 40-64 years. The association between prostate cancer and comorbidities commonly seen in diabetic patients suggests a more complicated scenario in the link between prostate cancer and diabetes at different disease stages.

Does diabetes mellitus increase the risk of high-grade prostate cancer in patients undergoing radical prostatectomy?

The objective was to test the hypothesis that in patients with prostate cancer undergoing radical prostatectomy (RP), diabetic patients are at a higher risk of harboring a high-grade tumor than non-diabetic patients. We examined 2060 consecutive men who underwent RP between 2001 and 2009. Of them, 7.1% had type 2 diabetes mellitus (DM). A high-grade tumor was defined as having a Gleason score ≥ 8. Univariable and multivariable logistic regression analyses were used to test the relationship between type 2 DM and high-grade tumor. Mean patient age was 64 years (range: 45-85). Mean total PSA level was 9 ng ml(-1) (range: 1-89.5). A significantly higher percentage of diabetic patients had high-grade tumor on biopsy (16.3 vs 7.6%; P = 0.001) and on RP specimen (21.1 vs 11.7%; P = 0.001) in comparison with non-diabetic patients. In multivariable analyses, DM was an independent predictor of high-grade tumor on biopsy (odds ratio = 2.31, P = 0.001) and on final pathological specimen (odds ratio = 2.22, P = 0.002). In patients undergoing RP, those with type 2 DM had a higher risk of harboring a poorly differentiated tumor on final pathological examination.

Glycemic control and prostate cancer progression: results from the SEARCH database

PURPOSE

Several studies have examined the association between diabetes mellitus (DM) and prostate cancer (PCa) risk and progression, however nearly all of these studies have compared diabetic versus non-diabetic men. We sought to investigate the role of glycemic control, as measured by HbA1c, on PCa aggressiveness and prognosis in men with DM and PCa from the Shared Equal Access Regional Cancer Hospital (SEARCH) database.

METHODS

We identified 247 men in SEARCH with DM and a recorded HbA1c value within the 12 months prior to radical prostatectomy between 1988 and 2009. We divided these men into tertiles by HbA1c level. The associations between HbA1c tertiles and risk of adverse pathology and biochemical recurrence were tested using multivariate logistic regression and Cox proportional hazards models, respectively.

RESULTS

Median HbA1c level was 6.9. On multivariate analysis, HbA1c tertiles were predictive of pathological Gleason score (P-trend = 0.001). Relative to the first tertile, men in the second (OR 4.68, P = 0.003) and third tertile (OR 6.60, P < 0.001) were more likely to have Gleason score > or = 4 + 3. HbA1c tertiles were not associated with margin status, node status, extracapsular extension or seminal vesicle invasion (all P-trend > 0.2). In the multivariate Cox proportional hazards model, increasing HbA1c tertiles were not significantly related to risk of biochemical recurrence (P-trend = 0.56).

CONCLUSION

Men with higher HbA1c levels presented with more biologically aggressive prostate tumors at radical prostatectomy. Although risk of recurrence was unrelated to HbA1c levels, further studies are needed to better explore the importance of glycemic control on long-term outcomes in diabetic men with PCa.

A changing world for DCvax: a PSMA loaded autologous dendritic cell vaccine for prostate cancer

BACKGROUND

Northwest Therapeutics' DCvax-prostate consists of autologous dendritic cells (DCs) loaded with prostate-specific membrane antigen (PSMA) peptides, administered intravenously. Phase I-II testing, a decade ago, showed clinical benefit and immunological response in some patients. More recently DCvax brain, a product using a similar DC platform showed encouraging Phase I-II results and sipleucel-T, a prostatic acid phosphatase (PAP)-directed DC immunotherapy had positive Phase III results.

OBJECTIVE

Features of the clinical setting into which a new immunotherapy could be introduced are discussed, to refine a perspective on DCvax-prostate in the context of evolving prostate cancer therapeutics. PSMA-directed therapeutics and immune anticancer technologies are reviewed, and the clinical and immunological correlative testing of DCvax-prostate is discussed.

METHODS

Clinical and preclinical data from peer-reviewed literature, meetings proceedings and manufacturer-provided information are considered.

CONCLUSION

DCvax-prostate had encouraging early-phase trial results, but development and testing had stalled. As a more detailed understanding of patient-selection for capacity for anticancer immune response, the quantitation of immunological correlates, and the changing marketplace develop, it is appealing to consider a well tolerated, PSMA-directed autologous dendritic cell therapeutic product. Further clinical trial development of DCvax-prostate is warranted, and required if it is to find a relevant clinical application.