Transdermal oestradiol and exercise in androgen deprivation therapy (ESTRACISE): protocol

OBJECTIVE

To report the protocol of a study evaluating the efficacy of transdermal oestradiol (E2) gel in reducing the adverse effects of androgen deprivation therapy (ADT), specifically on sexual function, and to assess the utility of E2 in combination with supervised exercise.

STUDY DESIGN AND METHODS

The primary endpoint of this open-label Phase IIA randomized controlled trial is the efficacy of transdermal E2 gel. Secondary endpoints include: (i) the occurrence of ADT-induced adverse effects; (ii) the safety and tolerability of E2; (iii) the impact of E2 with or without exercise on physical, physiological, muscle, and systemic biomarkers; and (iv) quality of life. The trial will recruit high-risk PCa patients (n = 310) undergoing external beam radiation therapy with adjuvant subcutaneous ADT. Participants will be stratified and randomized in a 1:1 ratio to either the E2 + ADT arm or the ADT-only control arm. Additionally, a subset of patients (n = 120) will be randomized into a supervised exercise programme.

RESULTS

The primary outcome is assessed according to the efficacy of E2 in mitigating the deterioration of Expanded Prostate Cancer Index Composite sexual function domain scores. Secondary outcomes are assessed according to the occurrence of ADT-induced adverse effects, safety and tolerability of E2, impact of E2 with or without exercise on physical performance, body composition, bone mineral density, muscle size, systematic biomarkers, and quality of life.

CONCLUSION

The ESTRACISE study's innovative design can offer novel insights about the benefits of E2 gel, and the substudy can reinforce the benefits resistance training and deliver valuable new novel insights into the synergistic benefits of E2 gel and exercise, which are currently unknown.

TRIAL REGISTRATION

The protocol has been registered in euclinicaltrials.eu (2023-504704-28-00) and in clinicaltrials.gov (NCT06271551).

MiR26a reverses enzalutamide resistance in a bone-tumor targeted system with an enhanced effect on bone metastatic CRPC

Resistance to androgen receptor (AR) inhibitors, including enzalutamide (Enz), as well as bone metastasis, are major challenges for castration-resistant prostate cancer (CRPC) treatment. In this study, we identified that miR26a can restore Enz sensitivity and inhibit bone metastatic CRPC. To achieve the highest combination effect of miR26a and Enz, we developed a cancer-targeted nano-system (Bm@PT/Enz-miR26a) using bone marrow mesenchymal stem cell (BMSC) membrane and T140 peptide to co-deliver Enz and miR26a. The in vitro/in vivo results demonstrated that miR26a can reverse Enz resistance and synergistically shrink tumor growth, invasion, and metastasis (especially secondary metastasis) in both subcutaneous and bone metastatic CRPC mouse models. We also found that the EZH2/SFRP1/WNT5A axis may be involved in this role. These findings open new avenues for treating bone metastatic and Enz-resistant CRPC.

Testosterone replacement therapy is not associated with increased prostate cancer incidence, prostate cancer-specific, or cardiovascular disease-specific mortality in Finnish men

BACKGROUND

Concerns have been expressed over the safety of testosterone replacement therapy (TRT) in men with late-onset hypogonadism (LOH). Previous studies have shown controversial results regarding the association of TRT with the risk of cardiovascular events or prostate cancer (PCa) incidence, aggressiveness, and mortality. This study explores the overall risk of PCa and risk by tumor grade and stage, as well as mortality from PCa and cardiovascular disease (CVD), among men treated with TRT compared to men without LOH and TRT use.

MATERIALS AND METHODS

The study included 78,615 men of age 55-67 years at baseline from the Finnish Randomized Study of Screening for Prostate Cancer (FinRSPC). Follow-up started at randomization and ended at death, emigration, or a common closing date January 1st, 2017. Cox proportional hazards regression model with time-dependent variables and adjustment for age, trial arm, use of other medications, and Charlson comorbidity index was used. Comprehensive information on TRT purchases during 1995-2015 was obtained from the Finnish National Prescription Database. PCa cases were identified from the Finnish Cancer Registry and causes of death obtained from Statistics Finland.

RESULTS

Over the course of 18 years of follow-up, 2919 men were on TRT, and 285 PCa cases were diagnosed among them. TRT users did not exhibit a higher incidence or mortality rate of PCa compared to non-users. On the contrary, men using TRT had lower PCa mortality than non-users (HR = 0.52; 95% CI 0.3-0.91). Additionally, TRT users had slightly lower CVD and all-cause mortality compared to non-users (HR = 0.87; 95% CI 0.75-1.01 and HR = 0.93; 95% CI 0.87-1.0, respectively). No time- or dose-dependency of TRT use was evident in any of the analyses.

CONCLUSION

Men using TRT were not associated to increased risk for PCa and did not experience increased PCa- or CVD-specific mortality compared to non-users. Further studies considering blood testosterone levels are warranted.

Statin Use, Cholesterol Level, and Mortality Among Females With Breast Cancer

Importance

Several studies have reported an association between the use of statins and breast cancer (BC) mortality. However, most of these studies did not take into account the underlying cholesterol level.

Objective

To investigate the association between serum cholesterol, statin use, and BC mortality.

Design, Setting, and Participants

This cohort study included females with invasive BC that was newly diagnosed between January 1, 1995, and December 31, 2013, in Finland. The cohort had available hormone receptor data and at least 1 cholesterol measurement. All data were obtained from Finnish national registries. Statistical analyses were performed from January to May 2022.

Exposure

Use of statins; statin dose; and serum cholesterol, low-density lipoprotein, high-density lipoprotein, and triglyceride levels measured separately before and after BC diagnosis.

Main Outcomes and Measures

Breast cancer mortality and overall mortality between date of BC diagnosis and December 31, 2015.

Results

A total of 13 378 female patients with BC (median [IQR] age, 62 [54-69] years) participated in the study. The median (IQR) follow-up was 4.5 (2.4-9.8) years after BC diagnosis, during which 16.4% of patients died and 7.0% died of BC. Prediagnostic statin use was a risk factor for BC death even after adjustment for total cholesterol level (hazard ratio [HR], 1.22; 95% CI, 1.02-1.46; P = .03). Reduced risk for BC death was seen for postdiagnostic statin use (HR, 0.85; 95% CI, 0.73-1.00; P = .05). The risk reduction was robust in participants whose cholesterol level decreased after starting statins (HR, 0.49; 95% CI, 0.32-0.75; P = .001) but was nonsignificant if cholesterol level did not subsequently decrease (HR, 0.69; 95% CI, 0.34-1.40; P = .30). Reduced BC mortality among statin users was also observed in females with estrogen receptor-positive tumors (HR, 0.82; 95% CI, 0.68-0.99; P = .03). Overall mortality was lower among statin users vs nonusers when adjusted for serum cholesterol level (HR, 0.80; 95% CI, 0.72-0.88; P < .001).

Conclusions and Relevance

Results of this cohort study showed that postdiagnostic use of statins was associated with reduced BC mortality compared with nonuse, and the risk was associated with subsequent change in serum cholesterol level. This finding suggests that cholesterol-lowering interventions with statins may be beneficial for patients with BC.

Adverse effects of an aldosterone synthase (CYP11B2) inhibitor, fadrozole (FAD286), on inflamed rat colon

Recently, we described local aldosterone production in the murine large intestine. Upregulated local aldosterone synthesis in different tissues has been linked with inflammatory conditions, which have been attenuated by the aldosterone synthase (CYP11B2) inhibitor, fadrozole (FAD286). Therefore, we investigated the effect of inhibition of intestinal aldosterone synthesis on the development of intestinal inflammation. Sprague-Dawley rats were administered 5% (v/w) dextran sodium sulphate (DSS) for 7 days with or without daily FAD286 (30 mg/kg/d) subcutaneous injections on 3 days before, during and one day after DSS. Tissue aldosterone concentrations were evaluated by ELISA, CYP11B2 by Western blot and RT-qPCR. FAD286 halved adrenal aldosterone production but, intriguingly, increased the colonic aldosterone concentration. The lack of inhibitory effect of FAD286 in the colon might have been affected by the smaller size of colonic vs. adrenal CYP11B2, as seen in Western blot. When combined with DSS, FAD286 aggravated the macroscopic and histological signs of intestinal inflammation, lowered the animals' body weight gain and increased the incidence of gastrointestinal bleeding and the permeability to iohexol in comparison to DSS-animals. To conclude, FAD286 exerted harmful effects during intestinal inflammation. Local intestinal aldosterone did not seem to play any role in the inflammatory pathogenesis occurring in the intestine.

Abstract 3904: Simvastatin intensifies anti-androgen efficacy against treatment-resistant prostate cancer cells

Androgen receptor (AR) signaling inhibitors (ARSIs) bicalutamide (Bic) and enzalutamide (Enza) are used in the treatment of castration resistant prostate cancer (CRPC). Prostate cancer (PCa) cells eventually develop treatment resistance against these drugs causing clinical challenges. The mechanisms behind treatment resistance are complex and only partially known. Androgen signaling is linked to lipid and cholesterol metabolism, and they likely play a role in the development of treatment resistance. Cholesterol producing mevalonate pathway can be inhibited by statins, but it is unknown whether statin treatment could enhance effects of ARSIs. We studied combined effects of simvastatin (Sim) with or without Bic or Enza in VCaP originated PCa cell lines resistant to these ARSIs. Unique treatment resistant cell lines were created with long-term cultures of VCaP cells. The cells were kept under anti-androgen influence until the cells were growing normally despite the ARSIs. We analyzed changes in cell growth, RNA expression, and relevant AR signaling and cholesterol metabolism protein expression. Prostate-specific antigen (PSA) secretion was measured as a marker of AR signaling activity. In Bic or Enza resistant cell lines, combination of 2.5 or 5 μM simvastatin + 10 μM Bic/Enza decreased cell growth more than Sim alone, i.e., ARSIs demonstrated efficacy in combination therapy against ARSI resistant cells. In Bic and Enza resistant cells, combination treatment increased the expression of 60 and 26 and decreased the expression of 33 and 48 genes, respectively, compared with simvastatin alone. Altogether, 16 genes expression changed similarly in both cell lines in response to combination therapy. In both cell lines, over 70% of all gene changes were seen on AR-regulated genes. In Bic resistant cells, Sim decreased PSA levels with or without Bic. On the contrary, in Enza resistant cells PSA levels were increased with combination of Sim and Enza. We showed that combined treatment with ARSI and Sim inhibited cell growth more than Sim alone in ARSI resistant cell lines. This suggests that inhibition of the mevalonate pathway could enhance androgen signaling inhibition and potentially circumvent ARSI resistance mechanisms. This phenomenon is supported by epidemiological studies as patients treated with anti-androgens responded better during simultaneous statin treatment. Gene expression differed in combination treatment compared to Sim alone. Future studies are needed on whether interventions on lipid and cholesterol metabolism could enhance treatment of CRPC. Knowledge about the precise mechanisms behind the treatment responses and resistance might lead to new therapeutic applications.

Citation Format: Aino Siltari, Olga Korhonen, Paavo Raittinen, Merja Bläuer, Heimo Syvälä, Teuvo L. Tammela, Teemu J. Murtola. Simvastatin intensifies anti-androgen efficacy against treatment-resistant prostate cancer cells. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3904.

Incidence of erectile dysfunction treatment after radical prostatectomy by Statin use in Finnish Nationwide Cohort Study

BACKGROUND

Erectile dysfunction (ED) is common after radical prostatectomy (RP) due to cavernous nerve damage. Risk of ED is also affected by vascular function. Statins prevent vascular events but their association with post-prostatectomy ED is unclear. We explored the likelihood of starting ED treatment after RP by statin use at the population level.

METHODS

The study cohort included 14,295 prostate cancer (PCa) patients with no ED treatment prior to diagnosis of PCa treated with RP in Finland during 1995-2013. Information on use of cholesterol-lowering drugs and ED medication during 1995-2014 and penile prosthesis implantation during 1996-2014 were gathered from national registries. Risk of ED treatment initiation after RP was analyzed by pre-diagnostic and post-diagnostic statin and non-statin cholesterol lowering (NSCL) drug use with Cox regression model.

RESULTS

Pre-diagnostic statin use or NSCL drug use overall had no association with risk of ED treatment initiation after RP. Post-diagnostic statin use was associated with a slightly increased risk of initiation of any ED treatment (HR = 1.07; 95% CI = 1.01-1.14). Patients with the longest duration of post-diagnostic statin use had a significantly decreased risk of PDE5 inhibitor initiation compared to non-users (HR = 0.43; 95% CI = 0.20-0.94). Among patients with no cardiovascular comorbidities, pre-diagnostic statin users had a significantly increased risk of initiation of injectable ED drugs (HR = 1.27; 95% CI = 1.04-1.55), however, no association with risk of any other ED treatment was observed.

CONCLUSION

Statin users have a slightly increased risk of ED treatment initiation after RP, which probably reflects the effect of the underlying vascular insufficiency.

How well do polygenic risk scores identify men at high risk for prostate cancer? Systematic review and meta-analysis

OBJECTIVES

Genome-wide association studies have revealed over 200 genetic susceptibility loci for prostate cancer (PCa). By combining them, polygenic risk scores (PRS) can be generated to predict risk of PCa. We summarize the published evidence and conduct meta-analyses of PRS as a predictor of PCa risk in Caucasian men.

PATIENTS AND METHODS

Data were extracted from 59 studies, with 16 studies including 17 separate analyses used in the main meta-analysis with a total of 20,786 cases and 69,106 controls identified through a systematic search of ten databases. Random effects meta-analysis was used to obtain pooled estimates of area under the receiver-operating characteristic curve (AUC). Meta-regression was used to assess the impact of number of single-nucleotide polymorphisms (SNPs) incorporated in PRS on AUC. Heterogeneity is expressed as I² scores. Publication bias was evaluated using funnel plots and Egger tests.

RESULTS

The ability of PRS to identify men with PCa was modest (pooled AUC 0.63, 95% CI 0.62-0.64) with moderate consistency (I² 64%). Combining PRS with clinical variables increased the pooled AUC to 0.74 (0.68-0.81). Meta-regression showed only negligible increase in AUC for adding incremental SNPs. Despite moderate heterogeneity, publication bias was not evident.

CONCLUSION

Typically, PRS accuracy is comparable to PSA or family history with a pooled AUC value 0.63 indicating mediocre performance for PRS alone.

Abstract 121: Differential resistance to hypoxia is linked to increased lipid accumulation in treatment resistant prostate cancer cells

Introduction: Solid tumors typically favor non-oxygen related pathways on utilizing energy for cell metabolism. This helps tumor cells to survive in hypoxic microenvironment which is common in solid tumors such as prostate cancer (PCa). PCa cells characteristically store lipids, especially cholesterol. Furthermore, hypoxia and lipid metabolism are both associated with decreased responses to immune system and resistance to cancer treatments. Aim of this study was to investigate the impact of hypoxia on cell proliferation and lipid metabolism in advanced PCa cells at various stages of treatment resistance.

Material and Methods: PCa cells, VCaPs, were cultured for months to form several unique, treatment resistant advanced PCa cell lines as follows: first, cells were cultured with high (10 nM) testosterone level until they required testosterone for growth to form testosterone sensitive cell line (VCaP-T, demonstrating metastatic hormone sensitive PCa); second, VCaP-T cells were cultured further under low testosterone (0.1 nM) until they gained ability to grow at low androgen level, forming castration resistant cell line (VCaP-CT); third, VCaP-CT cells were further cultured with bicalutamide and/or enzalutamide, androgen signaling inhibitors, until they again gained ability to grow despite the treatment, forming cell lines resistant to these drugs (VCaP-CT-BR, VCap-CT-ER, and VCaP-CT-BR-ER, demonstrating bicalutamide-, enzalutamide-, or mutually resistant cell lines, respectively).All cell lines were exposed to hypoxia (3% O2) with or without simvastatin (1 and 2.5 μM) for 3 days and compared to the cells growing in normoxia. Changes in proliferation was measured using crystal violet staining and amount of intracellular lipids were evaluated using Oil Red O staining.

Results: Hypoxia decreased cell proliferation compared to normoxia by 20-25% in VCaP-T, VCaP-CT, and VCaP-CT-BR cells, but had no impact in enzalutamide-resistant cells VCaP-CT-ER or VCaP-CT-BR-ER. Simvastatin treatment decreased cell proliferation in all cell lines equally in hypoxia and normoxia.Compared to androgen-sensitive VCaP-T cells, all treatment resistant cell lines displayed greater intracellular lipid accumulation. Further analyses will address whether hypoxia and/or simvastatin treatment impacts amount of intracellular lipids and whether inhibition of lipid accumulation leads to less tolerance to hypoxia.

Conclusion: Enzalutamide resistant cell lines displayed greater hypoxia tolerance compared to androgen sensitive or treatment naïve castration resistant cells. This indicates these cells are adopted to hypoxic microenvironment. All treatment resistant cell lines had greater intracellular lipid accumulation compared to testosterone-sensitive cells, suggesting importance of lipid metabolism in treatment resistance and hypoxia tolerance.

Citation Format: Aino Siltari, Merja Bläuer, Heimo Syvälä, Teuvo L. Tammela, Teemu J. Murtola. Differential resistance to hypoxia is linked to increased lipid accumulation in treatment resistant prostate cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 121.

Abstract CT171: Can supervised exercise impact on metabolic markers and physical activity during androgen-deprivation therapy in prostate cancer patients? - randomized controlled pilot trial

Introduction: Androgen-deprivation therapy (ADT) is standard in treatment of advanced prostate cancer (PCa). Common adverse effects include fatigue, weight gain, sarcopenia, and decreased libido leading to lowered quality of life (QoL). Supervised exercise improves overall QoL among PCa patients. Less is known, however, how it may affect metabolic adverse effects of ADT.The aim of the study was to explore the effect of exercise intervention on glucose and cholesterol levels, body composition, and to find out whether supervised exercise leads to greater physical activity in long-term compared to self-administered exercise in men with ADT.

Materials and methods: Altogether, 45 men were recruited. One man withdrew the consent at baseline and 5 dropped out during the study. Thus, 39 men completed the study. Subjects were randomly assigned into either supervised exercise for 3 months (n=27) or control group of self-administered exercise (n=17). In the supervised group, participants attended 1.5-hour group exercise session twice per week. Training program included both aerobic and muscle strength exercises. The 3-month intervention was followed by 3-month follow-up of self-administered exercise. Control group received the same introduction to exercise and training instruction as the supervised group but exercised independently for the entire study period. Fasting cholesterol, plasma glucose, and body composition were evaluated at the baseline, 3 months after randomization, and at the end of the study, 6 months after randomization. Physical activity during the study period was measured using activity bracelets (Polar A370). Study protocol was approved by Pirkanmaa hospital ethics committee (R18021) and registered to Clinicaltrials.gov (NCT04050397).

Results: Median total cholesterol increased during 6-month follow-up in both groups, but less in the supervised group compared to the control group (0.1 vs 0.4 mmol/l, respectively, p=0.02). LDL remained stable in supervised group but increased slightly in the control group (0 vs. 0.4 mmol/l, respectively, p=0.01). Fasting plasma glucose lowered slightly in both groups (-0.2 vs -0.4 mmol/l). Total active time per day was slightly higher in the supervised group compared to the control group after 3-month intervention (median 364 vs 293 min/day, respectively). This difference persisted after intervention stopped (median 331 vs 267 min/day, respectively). Median change in body fat percentage at 6 months was 0 in the supervised arm and -0.9 in the control arm. None of the participants dropped out due to exercise-related side-effects.

Conclusion: This pilot study showed that it is safe to perform strength exercise in men with ADT. Supervised exercise is likely more effective in mitigating metabolic adverse effect of ADT and inducing long-term changes in physical activity than self-administered exercise. Larger studies with longer follow-up are needed to investigate whether this leads to survival advantage.

Citation Format: Lauri Rantaniemi, Aino Siltari, Eeva Harju, Teemu J. Murtola. Can supervised exercise impact on metabolic markers and physical activity during androgen-deprivation therapy in prostate cancer patients? - randomized controlled pilot trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT171.

Randomised double-blind phase 3 clinical study testing impact of atorvastatin on prostate cancer progression after initiation of androgen deprivation therapy: study protocol

INTRODUCTION

Blood cholesterol is likely a risk factor for prostate cancer prognosis and use of statins is associated with lowered risk of prostate cancer recurrence and progression. Furthermore, use of statins has been associated with prolonged time before development of castration resistance (CR) during androgen deprivation therapy (ADT) for prostate cancer. However, the efficacy of statins on delaying castration-resistance has not been tested in a randomised placebo-controlled setting.This study aims to test statins' efficacy compared to placebo in delaying development of CR during ADT treatment for primary metastatic or recurrent prostate cancer. Secondary aim is to explore effect of statin intervention on prostate cancer mortality and lipid metabolism during ADT.

METHODS AND ANALYSIS

In this randomised placebo-controlled trial, a total of 400 men with de novo metastatic prostate cancer or recurrent disease after primary treatment and starting ADT will be recruited and randomised 1:1 to use daily 80 mg of atorvastatin or placebo. All researchers, study nurses and patients will be blinded throughout the trial. Patients are followed until disease recurrence or death. Primary outcome is time to formation of CR after initiation of ADT. Serum lipid levels (total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL) and trigyserides) are analysed to test whether changes in serum cholesterol parameters during ADT predict length of treatment response. Furthermore, the trial will compare quality of life, cardiovascular morbidity, changes in blood glucose and circulating cell-free DNA, and urine lipidome during trial.

ETHICS AND DISSEMINATION

This study is approved by the Regional ethics committees of the Pirkanmaa Hospital District, Science centre, Tampere, Finland (R18065M) and Tarto University Hospital, Tarto, Estonia (319/T-6). All participants read and sign informed consent form before study entry. After publication of results for the primary endpoints, anonymised summary metadata and statistical code will be made openly available. The data will not include any information that could make it possible to identify a given participant.

TRIAL REGISTRATION NUMBER

Clinicaltrial.gov: NCT04026230, Eudra-CT: 2016-004774-17, protocol code: ESTO2, protocol date 10 September 2020 and version 6.

Evidence for local aldosterone synthesis in the large intestine of the mouse

Aldosterone, the main physiological mineralocorticoid, regulates sodium and potassium balance in the distal convoluted tubule of the kidney. Aldosterone is synthesized from cholesterol in the adrenal cortex in a sequence of enzymatic steps. Recently however, several tissues or cells e.g. brain, heart, blood vessels, kidneys and adipocytes have been shown to possess capability to produce aldosterone locally, and there is some evidence that this occurs also in the intestine. Colon expresses mineralocorticoid receptors and is capable of synthesizing corticosterone, the second last intermediate on the route to aldosterone from cholesterol. Based on such reports and on our preliminary finding, we hypothesized that aldosterone could be synthesized locally in the intestine and therefore we measured the concentration of aldosterone as well as the protein and gene expression of aldosterone synthase (CYP11B2), an enzyme responsible on aldosterone synthesis, from the distal section of the gastrointestinal tract of 10-week-old Balb/c male mice. It is known that sodium deficiency regulates aldosterone synthesis in adrenal glands, therefore we fed the mice with low (0.01%), normal (0.2%) and high-sodium (1.6%) diets for 14 days. Here we report that, aldosterone was detected in colon and cecum samples. Measurable amounts of CYP11B2 protein were detected by Western blot and Elisa analysis from both intestinal tissues. We detected CYP11B2 gene expression from the large intestine along with immunohistochemical findings of CYP11B2 in colonic wall. Sodium depletion increased the aldosterone concentration in plasma compared to control and high-sodium groups as well as in the intestine compared to mice fed with the high-sodium diet. To summarize, this study further supports the presence of aldosterone and the enzyme needed to produce this mineralocorticoid in the murine large intestine.

Statins for Prostate Cancer: When and How Much?

Statins have plausible biological effects against prostate cancer cells and are associated with improved disease-specific mortality. In current randomized placebo-controlled trial, low-dose atorvastatin caused no difference in relapses after radical prostatectomy in Asian men. Future trials should study higher statin doses at later disease stages with survival as the endpoint.See related article by Jeong et al., p. 5004.

Pharmacoepidemiological Evaluation in Prostate Cancer-Common Pitfalls and How to Avoid Them

Simple Summary

Pharmacoepidemiologic research provides opportunities to evaluate how commonly used drug groups, such as cholesterol-lowering drugs, may affect the prostate cancer risk or mortality. However, such studies need to be carefully designed in order to avoid biases caused by systematic differences between medication users and non-users. Similarly, data must be carefully analyzed and interpreted while acknowledging possible biases that can lead to erroneous conclusions. Here, we review common pitfalls in such studies and describe ways to avoid them in an effort to aid future research.

Abstract

Pharmacoepidemiologic research provides opportunities to evaluate how commonly used drug groups, such as cholesterol-lowering or antidiabetic drugs, may affect the prostate cancer risk or mortality. This type of research is valuable in estimating real-life drug effects. Nonetheless, pharmacoepidemiological studies are prone to multiple sources of bias that mainly arise from systematic differences between medication users and non-users. If these are not appreciated and properly controlled for, there is a risk of obtaining biased results and reaching erroneous conclusions. Therefore, in order to improve the quality of future research, we describe common biases in pharmacoepidemiological studies, particularly in the context of prostate cancer research. We also list common ways to mitigate these biases and to estimate causality between medication use and cancer outcomes.

Preservation of Endopelvic Fascia: Effects on Postoperative Incontinence and Sexual Function - A Randomized Clinical Trial

BACKGROUND

Urinary incontinence and sexual dysfunction are common after robot-assisted radical prostatectomy (RALP). New surgical techniques to improve these functions after the operation are under evaluation for example, preservation of endopelvic fascia during RALP. However, the benefits of this technique have not been critically scrutinized in a randomized setting.

AIM

In this study, we compared endopelvic fascia preserving operation with the standard surgical procedure in a randomized trial at the Tampere University Hospital, Finland.

METHODS

A total of 158 men with localized prostate cancer and scheduled for RALP were randomized 1:1 into endopelvic fascia-preserving RALP or a control group that is, standard operation. All operations were performed by a single surgeon.

OUTCOMES

Urinary and sexual function were evaluated by the Expanded Prostate Cancer Index Composite-26 questionnaire at baseline and 3, 6, and 12 months after the surgery.

RESULTS

There was no difference in urinary incontinence or sexual function between the groups at any time point (urinary incontinence domain at 12 months after RALP for fascia preserving and control group 73.6 ± 3 vs 78.9 ± 2.5 and sexual domain 43 ± 3.2 vs 40.3 ± 3, respectively). Clinical and pathologic tumor characteristics, duration of surgery, blood loss, rate of complications, and time to hospital discharge were similar between the study arms. Compliance of filling out the Expanded Prostate Cancer Index Composite-26 questionnaire varied from 91% to 98%, with no difference between study arms.

CLINICAL IMPLICATIONS

Based on our results, endopelvic fascia preservation alone during RALP is not recommended over the standard surgical method.

STRENGTHS & LIMITATIONS

This is a randomized clinical study with sufficient statistical power. As a limitation, only a minority of participants underwent magnetic resonance imaging before the operation, thus we could not evaluate the role of urethral length or shape of the prostate. Urinary and sexual function results are based on questionnaires filled out by the patients, however, participants completed the surveys independently unassisted by health care personnel.

CONCLUSION

Endopelvic fascia-preserving RALP does not improve urinary continence or sexual function as compared with the standard surgical technique. Future studies aiming to improve functional outcomes after RALP should focus on evaluating other technique modifications. Siltari A, Riikonen J, Murtola TJ. Preservation of Endopelvic Fascia: Effects on Postoperative Incontinence and Sexual Function - A Randomized Clinical Trial. J Sex Med 2021;18:327-338.

Preservation of Endopelvic Fascia: Effects on Postoperative Incontinence and Sexual Function - A Randomized Clinical Trial

BACKGROUND

Urinary incontinence and sexual dysfunction are common after robot-assisted radical prostatectomy (RALP). New surgical techniques to improve these functions after the operation are under evaluation for example, preservation of endopelvic fascia during RALP. However, the benefits of this technique have not been critically scrutinized in a randomized setting.

AIM

In this study, we compared endopelvic fascia preserving operation with the standard surgical procedure in a randomized trial at the Tampere University Hospital, Finland.

METHODS

A total of 158 men with localized prostate cancer and scheduled for RALP were randomized 1:1 into endopelvic fascia-preserving RALP or a control group that is, standard operation. All operations were performed by a single surgeon.

OUTCOMES

Urinary and sexual function were evaluated by the Expanded Prostate Cancer Index Composite-26 questionnaire at baseline and 3, 6, and 12 months after the surgery.

RESULTS

There was no difference in urinary incontinence or sexual function between the groups at any time point (urinary incontinence domain at 12 months after RALP for fascia preserving and control group 73.6 ± 3 vs 78.9 ± 2.5 and sexual domain 43 ± 3.2 vs 40.3 ± 3, respectively). Clinical and pathologic tumor characteristics, duration of surgery, blood loss, rate of complications, and time to hospital discharge were similar between the study arms. Compliance of filling out the Expanded Prostate Cancer Index Composite-26 questionnaire varied from 91% to 98%, with no difference between study arms.

CLINICAL IMPLICATIONS

Based on our results, endopelvic fascia preservation alone during RALP is not recommended over the standard surgical method.

STRENGTHS & LIMITATIONS

This is a randomized clinical study with sufficient statistical power. As a limitation, only a minority of participants underwent magnetic resonance imaging before the operation, thus we could not evaluate the role of urethral length or shape of the prostate. Urinary and sexual function results are based on questionnaires filled out by the patients, however, participants completed the surveys independently unassisted by health care personnel.

CONCLUSION

Endopelvic fascia-preserving RALP does not improve urinary continence or sexual function as compared with the standard surgical technique. Future studies aiming to improve functional outcomes after RALP should focus on evaluating other technique modifications. Siltari A, Riikonen J, Murtola TJ. Preservation of Endopelvic Fascia: Effects on Postoperative Incontinence and Sexual Function - A Randomized Clinical Trial. J Sex Med 2021;18:327-338.

Urine colour as an indicator for anastomotic leakage after robot-assisted radical prostatectomy

Objectives: To determine whether macroscopic haematuria predicts urethrovesical anastomotic leakage after robot-assisted laparoscopic radical prostatectomy (RALP) as well as a cystogram.Patients and methods: Participants were recruited before cystogram and catheter removal 5-14 days after RALP surgery. Urine colour in the collection bag was classified according to a three-step scale (clear, light red and dark red) and leakages in cystogram were graded with a four-step scale (Grade 0-3). Diagnostic accuracy parameters were calculated for urine colour. A multivariate logistic regression model was used to evaluate other leakage risk factors.Results: Of 214 patients, 201 (94%) had clear, six (3%) had light red and seven (3%) had dark red coloured urine. In the cystogram, 20 (9%) patients had leakage; 14 had Grade 1, five Grade 2 and one Grade 3 leakage. Overall, specificity and sensitivity of urine colour in predicting anastomotic leakage were 0.97 (95% CI = 0.95-100) and 0.38 (95% CI = 0.17-0.59), respectively. Negative and positive predictive values were 94% and 62%, respectively. Other significant risk factors for anastomotic leakage were previous transurethral resection or radiation therapy to the prostate, non-waterproof anastomosis at surgery, postoperative pelvic haematoma, long catheterization and surgeon's inexperience. In patients with no other risk factors, test sensitivity improved to 0.80 (95% CI = 0.45-1.15) and negative and positive predictive values to 99% and 44%, respectively.Conclusion: This prospective single-arm trial indicates that in patients with clear urine and no other risk factors for anastomotic leakage, a cystogram examination before urethral catheter removal can be safely omitted.

Effects of Preoperative Atorvastatin Treatment On Erectile Function After Radical Prostatectomy: Results From a Subgroup of ESTO1, a Randomized, Double-Blind, Placebo-Controlled Study

INTRODUCTION

Erectile dysfunction is common after radical prostatectomy because of damage to the cavernous nerves. Thus, it is important to identify new ways to avoid this problem. For example, statins have shown positive effects on erectile function and may have anti-inflammatory effects that improve recovery after surgery.

AIM

The aim of this exploratory analysis of a subgroup from ESTO1, a randomized, double-blind, placebo-controlled study, was to evaluate the preoperative use of atorvastatin on erectile function after radical prostatectomy.

METHOD

Patients were randomized to either 80 mg atorvastatin or placebo daily before undergoing radical prostatectomy from study inclusion to the day of surgery. Altogether 118 men with prostate cancer and scheduled for radical prostatectomy were asked to fill out the 5-item version of the International Index of Erectile Function (IIEF-5) questionnaire before surgery and at 3, 6, 9, and 12 months after surgery.

MAIN OUTCOME MEASUREMENTS

The study was exploratory, with the main outcome being the overall difference between IIEF-5 scores in the 2 groups at 12 months. Several hypotheses generating sub-analyses were conducted.

RESULTS

Overall, 85% filled out the IIEF-5 questionnaire before their operation and 85%, 81%, 78%, and 78% completed it at 3, 6, 9, and 12 months follow-up, respectively. 52% of men had information available at all time points. There were no statistically significant differences between the groups at baseline in either erectile function, comorbidities, or tumor characteristics. The median duration of use of atorvastatin and placebo before surgery was 27 and 25 days, respectively. Preoperative atorvastatin treatment had no statistically significant effect on erectile function after prostatectomy as compared with placebo, although IIEF-5 scores were higher at all time points in the statin arm. Furthermore, atorvastatin treatment compared with placebo improved IIEF-5 scores at 12 months after surgery when the cavernous nerves were at least partially intact bilaterally (P < .04, n = 65); however, after full bilateral or unilateral nerve-sparing, the difference was not statistically significant.

CLINICAL IMPLICATION

Short-term statin treatment did not improve recovery of erectile function after prostatectomy; however, further studies are needed before final conclusions.

STRENGTHS & LIMITATIONS

This was a randomized placebo-controlled study. Original ESTO1 study was designed to detect a difference in prostate cancer biomarkers.

CONCLUSION

Short-term atorvastatin treatment before radical prostatectomy had no statistically significant effect on the recovery of erectile functions in a non-selected cohort of patients undergoing radical prostatectomy. Further studies will be needed to clarify the role of long-term atorvastatin use before and after prostatectomy. Siltari A, Riikonen J, Fode M, et al. Effects of Preoperative Atorvastatin Treatment On Erectile Function After Radical Prostatectomy: Results From a Subgroup of ESTO1, a Randomized, Double-Blind, Placebo-Controlled Study. J Sex Med 2019;16:1597-1605.

Age-related changes in the local intestinal renin-angiotensin system in normotensive and spontaneously hypertensive rats

Local renin-angiotensin systems (RAS) are found in many tissues. The main physiological effects of RAS are driven by the balance between two pathways: the angiotensin-converting enzyme I - angiotensin II receptor type 1 (ACE1-AT1R) axis and the angiotensin-converting enzyme 2 - Mas-receptor (ACE2-MAS) axis. The local intestinal RAS functions both as a paracrine regulator and as a regulator of inflammation. The expression of local RAS is known to change with age in many tissues, but age-related changes in the intestinal RAS have not been studied comprehensively. The present study characterized age-related changes in two main pathways of local RAS in the jejunum and colon of young and adult rats, in normotensive and hypertensive strains. The main finding was that 33-week-old rats exhibit an increased ratio of ACE1/ACE2 activities and protein quantity ratios compared to young rats. As the relationship of ACE1 and ACE2 mediated pathways drives the total physiological effects of RAS, the results indicate that the function of intestinal RAS changes with age. It is possible that age-related increase in ACE1-AT1R axis introduces more pro-inflammatory and fibrogenic conditions in the intestine.

Antihypertensive drugs and prostate cancer risk in a Finnish population-based cohort

BACKGROUND

The etiology of prostate cancer (PCa) involves environmental and genetic factors. Understanding the role of medication use on PCa risk may clarify the pathophysiological changes and mechanisms in development of cancer.

METHODS

This study investigated PCa risk in relation to overall use of anti-hypertensive drugs and those with specific mechanisms of action. The study cohort (78,615 men) was linked to the prescription database to obtain information on medication use during 20-year follow-up. Information was obtained on PCa diagnoses, causes of deaths, and for a sub-set on B.M.I. and use of non-prescription drugs. Time-dependent drug use variables hazard ratios (HR) with 95% confidence intervals (CI) were calculated using Cox regression analyses.

RESULTS

Use of antihypertensive drugs slightly increased PCa risk (HR = 1.16, 95% CI = 1.11-1.22). The risk increase was clearest for metastatic PCa (HR = 1.36, 95% CI = 1.14-1.62). ACE inhibitors, beta-blockers, and diuretics were all separately associated with a small excess risk (HR = 1.10, 95% CI = 1.01-1.19, HR = 1.14, 95% CI = 1.06-1.21, and HR = 1.16, 95% CI = 1.07-1.27, respectively). None of the other groups showed a clear association with PCa risk.

CONCLUSIONS

The use of antihypertensive drugs was associated with increased prostate cancer risk. Similar risk association for multiple drug groups suggests that the findings may not reflect a direct medication effect, but may be due to underlying hypertension.

Effect of Aging on the Absorption of Small Peptides in Spontaneously Hypertensive Rats

In the present study, we aimed to evaluate the effect of aging on the absorption of small peptides in spontaneously hypertensive rats (SHRs). Three kinds of dipeptides, glycyl-sarcosine (Gly-Sar), Trp-His, and captopril (a dipeptidomimetic drug), a Gly-Sar-Sar tripeptide, a Gly-Sar-Sar-Sar tetrapeptide, and a Gly-Sar-Sar-Sar-Sar pentapeptide were administered at doses of 10 mg/kg each to 8- and 40-week-old SHRs. The peptides were all detected in their intact forms in the blood. There was a significantly promoted absorption of di/tripeptides in aged SHRs compared with young SHRs. In contrast, the absorption of tetra/pentapeptides was not affected by aging. PepT1 expression in the mid-jejunum was significantly increased in 40-week-old SHRs compared with 8-week-old SHRs, whereas aging did not alter the expression of claudin-1, a tight junction related protein. Thus, the present results suggest that SHR aging may enhance the absorption of di/tripeptides through the enhanced PepT1 transport route, although oligopeptides may be absorbed in an age-independent manner.

Vascular Calcification, Vitamin K and Warfarin Therapy - Possible or Plausible Connection?

Atherosclerosis is a pathological process underpinning many cardiovascular diseases; it is the main cause of global mortality. Atherosclerosis is characterized by an invasion of inflammatory cells, accumulation of lipids and the formation of fatty streaks (plaques) which subsequently allow accumulation of calcium and other minerals leading to a disturbance in the vascular endothelium and its regulatory role in arterial function. Vascular calcification is a different process, stringently regulated mainly by local factors, in which osteoblast-like cells accumulate in the muscular layer of arteries ultimately taking on the physiological appearance of bone. The elevated stiffness of the arteries leads to severe vascular complications in brain, heart and kidneys. Recently, evidence from animal experiments as well as clinical and epidemiological results suggests that long-term treatment with warfarin, but not with the novel direct anticoagulants, can increase the risk or even induce vascular calcification in some individuals. Gamma-carboxylation is an enzymatic process not only needed for activation of vitamin K but also other proteins which participate in bone formation and vascular calcification. Thus, reduced expression of the vitamin K-dependent proteins which physiologically inhibit calcification of cellular matrix could be postulated to lead to vascular calcification. Published clinical data, describing at present a few thousand patients, need to be supplemented with controlled studies to confirm this interesting hypothesis.

Long-term feeding with bioactive tripeptides in aged hypertensive and normotensive rats: special focus on blood pressure and bradykinin-induced vascular reactivity

Bradykinin is the main player of the kallikrein-kinin system. Bradykinin-induced vasodilatation is age-dependent; this is believed to be associated with the level of expression of the two bradykinin receptors (BR1 and BR2) in the vasculature. The aim of this study was to clarify bradykinin-induced vascular reactivity of spontaneously hypertensive rats (SHR) and age-matched Wistar-Kyoto rats (WKY) after 6 weeks' consumption of a drink containing bioactive tripeptides (Ile-Pro-Pro, Val-Pro-Pro and Leu-Pro-Pro). Two age groups were used: young (10 weeks at the end of experiment) and old (24 weeks). Blood pressure was monitored weekly by the tail-cuff method. After six weeks, vascular reactivity was assessed in vitro in mesenteric artery rings focusing on bradykinin induced activity. Blood pressure was lowered in old SHR after 6 weeks' tripeptide consumption compared to water drinking controls (P < 0.05). Blood pressure was lowered by peptide consumption also in old WKY (P < 0.05) but tripeptide consumption exerted no effect on the blood pressure of young animals. Old SHR suffered from endothelial and smooth muscle dysfunction which was not improved by these tripeptides. Interestingly, bradykinin caused vasoconstriction even in young SHR; this was blocked by a non-selective cyclooxygenase (COX) inhibitor but not by a B1 and B2 receptor antagonist. The expressions of mRNA of COX-1 and COX-2 in aorta were slightly upregulated in old SHR. ACE-1 activity in aorta and protein level in kidney, but not ACE-1 mRNA expression was upregulated in old animals (P < 0.05). To conclude, long-term feeding with a drink containing tripeptides lowers or prevents the age-associated increase in blood pressure in hypertensive and normotensive animals. ACE-1 activity, protein level but not mRNA expression are elevated in old animals. We also demonstrated that the vascular inflammation and dysfunction present in aged hypertensive animals cause bradykinin to induce vasoconstriction; this is not prevented by tripeptide feeding but involves the prostaglandin pathway.

Bradykinin -induced vasodilatation: Role of age, ACE1-inhibitory peptide, mas- and bradykinin receptors

Bradykinin exerts its vascular actions via two types of receptors, the non-constitutively expressed bradykinin receptor type 1 (BR1) and the constitutive type 2 receptor (BR2). Bradykinin-induced vasorelaxation is age-dependent, a phenomenon related to the varying amounts of BR1 and BR2 in the vasculature. Isoleucine-proline-proline (Ile-Pro-Pro), a bioactive tripeptide, lowers elevated blood pressure and improves impaired endothelium-dependent vasorelaxation in hypertensive rats. It inhibits angiotensin converting enzyme 1 (ACE1). Other mechanisms of action have also been postulated. The aims of the study were to clarify the underlying mechanisms of the age-dependency of bradykinin-induced vasodilatation such as the roles of the two bradykinin receptors, the mas-receptor and synergism with Ile-Pro-Pro. The vascular response studies were conducted using mesenteric artery and aorta rings from normotensive 6 wk. (young) and 22 wk. (old) Wistar rats. Cumulative dosing of acetylcholine, bradykinin and angiotensin(1-7) (Ang(1-7))were tested in phenylephrine-induced vasoconstriction with or without 10min pre-incubation with antagonists against BR1-, BR2- or mas-receptors, Ang(1-7) or ACE1-inhibitors captopril and Ile-Pro-Pro. The bradykinin-induced vasorelaxation in vitro was age-dependent and it was improved by pre-incubation with Ile-Pro-Pro, especially in old rats with endothelial dysfunction. The mas-receptor antagonist, D-Pro₇-Ang(1-7) abolished bradykinin-induced relaxation totally. Interestingly, BR1 and BR2 antagonists only slightly reduced bradykinin-induced vasorelaxation, as an evidence for the involvement of other mechanisms in addition to receptor activation. In conclusion, bradykinin-induced vasorelaxation was age-dependent and Ile-Pro-Pro improved it. Mas receptor antagonist abolished relaxation while bradykinin receptor antagonist only slightly reduced it, suggesting that bradykinin-induced vasorelaxation is regulated also by other mechanisms than the classical BR1/BR2 pathway.

Does the cis/trans configuration of peptide bonds in bioactive tripeptides play a role in ACE-1 enzyme inhibition?

Background

The milk casein-derived bioactive tripeptides isoleucine-proline-proline (IPP) and valine-proline-proline (VPP) have been shown to prevent development of hypertension in animal models and to lower blood pressure in moderately hypertensive subjects in most but not all clinical trials. Inhibition of angiotensin-converting enzyme 1 (ACE-1) has been suggested as the explanation for these antihypertensive and beneficial vascular effects. Previously, human umbilical vein endothelial cells (HUVEC) have not been used to test ACE-1 inhibiting properties of casein derived tripeptides in vasculature.

Purpose

We focused on the cis/trans configurations of the peptide bonds in proline-containing tripeptides in order to discover whether the different structural properties of these peptides influence their activity in ACE-1 inhibition. We hypothesized that the configuration of proline-containing peptides plays a significant role in enzyme inhibition.

Methods

AutoDock 4.2 docking software was used to predict suitable peptide bond configurations of the tripeptides. Besides modeling studies, we completed ACE-1 activity measurements in vitro using HUVEC cultures.

Results

In HUVEC cells, both IPP and VPP inhibited ACE-1. Based on molecular docking studies, we propose that in ACE-1 inhibition IPP and VPP share a similar cis configuration between the first aliphatic (isoleucine or valine) and the second (proline) amino acid residues and more different configurations between two proline residues. In vivo experiments are needed to validate the significance of the present findings.