Calcium and vitamin D supplementation during androgen deprivation therapy for prostate cancer: a critical review

Cancer treatment-induced bone loss

Cancer treatment-induced bone loss (CTBL) is associated with anti-tumor treatments, including endocrine therapies, chemotherapeutic treatments, radiotherapy, glucocorticoids, and tyrosine kinase inhibitors. Osteoporosis, characterized by the loss of bone mass, can increase the risk of fractures, leading to mortality and long-term disability, even after cancer remission. Cancer and osteoporosis have marked clinical and pathogenetic similarities. Both have a multifactorial etiology, affect the geriatric population, and markedly influence quality of life. Lifestyle management, including calcium and vitamin D supplementation, is recommended but the supporting evidence is limited. Oral and injectable bisphosphonates are effective for osteoporosis and malignant bone disease. Bisphosphonates increase bone mineral density (BMD) in patients with CTBL. Denosumab is also used in the management of CTBL; in clinical trials, it improved BMD and reduced the risk of fracture. Currently, there are no bone anabolic therapies for patients with cancer. Appropriate therapies are necessary to maintain optimal bone health, particularly in patients at heightened risk.

Development of a Multidisciplinary Care Pathway for Fracture Prevention in Men with Prostate Cancer at Initiation of Androgen Deprivation Therapy

Fracture risk is increased in men with prostate cancer (PCa) receiving Androgen Deprivation Therapy (ADT). However, routine assessment of fracture risk is often not systematically applied. We aimed to establish a comprehensive care pathway for fracture prevention in men with PCa starting ADT. Therefore, a multidisciplinary working group designed and implemented a care pathway using the 'Knowledge to Action' framework, based on current Dutch guidelines for PCa, osteoporosis and fracture prevention, and an extensive literature review of other guidelines. The pathway was developed according to a five-step clinical approach including case finding, fracture risk assessment based on risk factors, bone mineral density test, vertebral fracture assessment, differential diagnosis, treatment, and annual follow-up. Our fracture prevention care pathway for patients with PCa at the time of ADT initiation was designed to promote a patient-centered, multidisciplinary approach to facilitate the implementation of early fracture prevention measures.

Balancing Hormone Therapy: Mitigating Adverse Effects of Androgen-Deprivation Therapy and Exploring Alternatives in Prostate Cancer Management

Androgen-deprivation therapy (ADT) is well established as the standard of care in metastatic prostate cancer (PCa) management; however, ADT has significant adverse effects (AEs) that must be addressed. This review aims to highlight opportunities to mitigate AEs of ADT and explore alternatives in PCa management. Specifically, we discuss behavioral and pharmacologic strategies for mitigating ADT AEs as well as ADT-sparing approaches for hormone-sensitive and castration-resistant PCa. Equipped with effective mitigation strategies and possible alternatives, clinicians and researchers can optimize health-related quality of life for patients currently receiving ADT for PCa and consider treatments that spare patients from AEs of ADT.

Flavones: The Apoptosis in Prostate Cancer of Three Flavones Selected as Therapeutic Candidate Models

Cancer is a widespread but dangerous disease that can strike anyone and is the second 1leading cause of death worldwide. Prostate cancer, in particular, is a prevalent cancer that occurs in men, and much research is being done on its treatment. Although chemical drugs are effective, they have various side effects, and accordingly, anticancer drugs using natural products are emerging. To date, many natural candidates have been discovered, and new drugs are being developed as drugs to treat prostate cancer. Representative candidate compounds that have been studied to be effective in prostate cancer include apigenin, acacetin and tangeretin of the flavone family among flavonoids. In this review, we look at the effects of these three flavones on prostate cancer cells via apoptosis in vitro and in vivo. Furthermore, in addition to the existing drugs, we suggest the three flavones and their effectiveness as natural anticancer agents, a treatment model for prostate cancer.

Management of cancer treatment-induced bone loss (CTIBL) in patients with breast cancer or prostate cancer

Breast cancer and prostate cancer are sex hormone-dependent cancers, and estrogen or androgen suppression therapy is the standard treatment. Cancer treatment-induced bone loss (CTIBL): bone loss and osteoporosis have become important side effects of these therapies. To summarize the current evidences, (1) Endocrine therapy for breast cancer and prostate cancer is associated with a significant decrease in bone mineral density. (2) Aromatase inhibitors (AI) for breast cancer are associated with a significant increase in fractures, and androgen deprivation therapy (ADT) for prostate cancer is likely to be associated with an increase in fractures. (3) Administration of bisphosphonates and denosumab increases bone mass in patients undergoing endocrine therapy for breast cancer. Administration of bisphosphonates, denosumab, and SERMs increased bone mass in patients undergoing ADT therapy for prostate cancer. (4) Bisphosphonates and denosumab reduce fracture risk in patients on AI for breast cancer, and toremifene and denosumab in patients on ADT for prostate cancer.

Vitamin D: sources, physiological role, biokinetics, deficiency, therapeutic use, toxicity, and overview of analytical methods for detection of vitamin D and its metabolites

Vitamin D has a well-known role in the calcium homeostasis associated with the maintenance of healthy bones. It increases the efficiency of the intestinal absorption of dietary calcium, reduces calcium losses in urine, and mobilizes calcium stored in the skeleton. However, vitamin D receptors are present ubiquitously in the human body and indeed, vitamin D has a plethora of non-calcemic functions. In contrast to most vitamins, sufficient vitamin D can be synthesized in human skin. However, its production can be markedly decreased due to factors such as clothing, sunscreens, intentional avoidance of the direct sunlight, or the high latitude of the residence. Indeed, more than one billion people worldwide are vitamin D deficient, and the deficiency is frequently undiagnosed. The chronic deficiency is not only associated with rickets/osteomalacia/osteoporosis but it is also linked to a higher risk of hypertension, type 1 diabetes, multiple sclerosis, or cancer. Supplementation of vitamin D may be hence beneficial, but the intake of vitamin D should be under the supervision of health professionals because overdosing leads to intoxication with severe health consequences. For monitoring vitamin D, several analytical methods are employed, and their advantages and disadvantages are discussed in detail in this review.

A Narrative Review of the Safety of Anti-COVID-19 Nutraceuticals for Patients with Cancer

Simple Summary

Dietary supplement use has increased more than 35% globally since the COVID-19 outbreak. While some nutraceuticals are potentially efficacious against severe disease from COVID-19, their indiscriminate use by patients with cancer without medical supervision is concerning. The aim of this narrative review was to evaluate the data on safety of “anti-COVID-19” nutraceuticals for patients with cancer. We found that the use of vitamin C, vitamin D, and selenium supplements is likely safe and even potentially beneficial at typically recommended doses. However, caution is advised regarding the use of omega-3 fatty acids and zinc, as risks from their use may outweigh the benefits.

Abstract

Interest in dietary supplements and their efficacy in treating and preventing disease has increased greatly since the outbreak of the COVID-19 pandemic. Due to the risk of severe COVID-19 in patients with cancer, we conducted a narrative review aiming to better understand the data on the safety of the most efficacious “anti-COVID-19” nutraceuticals for patients with cancer. We conducted a PubMed database search aimed at identifying the most effective nutrients for use against COVID-19. For the identified nutraceuticals, we searched PubMed again regarding their safety for patients with cancer. Fifty-four total records (52 independent studies) were retrieved, pertaining to vitamin D, vitamin C, selenium, omega-3 fatty acids, and zinc. Vitamin D results from 23 articles indicated safe use, but two articles indicated potential harm. All 14 articles for vitamin C and five out of six articles for selenium indicated the safety of use (one study for selenium suggested harm with high-dose supplementation). Results for omega-3 fatty acids (seven articles) and zinc (one article), however, were rather mixed regarding safety. We conclude that vitamin D, vitamin C, and selenium supplements are likely safe or even beneficial at typically recommended doses; however, caution is urged with omega-3 fatty acid supplements, and zinc supplements should likely be avoided. More experimental research is needed, and nutraceutical use by patients with cancer should always be under the supervision of a healthcare team.

Effects of High-Dose Vitamin D Supplementation on Phase Angle and Physical Function in Patients with Prostate Cancer on ADT

PURPOSE

Androgen deprivation therapy (ADT) is commonly used to treat patients with advanced prostate cancer but is associated with functional decline. Bioelectrical impedance analysis (BIA)-derived phase angle may reflect frailty and functional decline in cancer patients. High-dose vitamin D supplementation may improve phase angle values and physical function.

METHODS

We conducted an exploratory analysis from a phase II randomized controlled trial investigating the efficacy of high-dose vitamin D supplementation in prostate cancer patients (age ≥ 60 yrs). Fifty-nine patients were randomized to high-dose vitamin D (600 IU/day plus 50,000 IU/week) or low-dose: RDA for vitamin D (600 IU/day plus placebo weekly) for 24 weeks. Phase angle was measured by BIA. Physical function measures included handgrip strength, 6-minute walk test, Short Performance Physical Battery and leg extension. All testing was completed at baseline, week 12 and week 24.

RESULTS

Phase angle values were wider over the entire study in the high-dose vitamin D arm indicating healthier muscle cells. The low-dose vitamin D arm had phase angle values consistent with frailty cutoffs in older men (<5.7°).

CONCLUSION

Patients in the high-dose vitamin D arm experienced wider phase angle values over the course of the study which may indicate less frailty. ClinicalTrials.gov ID: NCT02064946.

Pathophysiology of Bone Loss in Patients with Prostate Cancer Receiving Androgen-Deprivation Therapy and Lifestyle Modifications for the Management of Bone Health: A Comprehensive Review

Androgen-deprivation therapy (ADT) is a systemic therapy administered for the management of advanced prostate cancer (PCa). Although ADT may improve survival, long-term use reduces bone mass density (BMD), posing an increased risk of fracture. Considering the long natural history of PCa, it is essential to preserve bone health and quality-of-life in patients on long-term ADT. As an alternative to pharmacological interventions targeted at preserving BMD, current evidence recommends lifestyle modifications, including individualized exercise and nutritional interventions. Exercise interventions include resistance training, aerobic exercise, and weight-bearing impact exercise, and have shown efficacy in preserving BMD. At the same time, it is important to take into account that PCa is a progressive and debilitating disease in which a substantial proportion of patients on long-term ADT are older individuals who harbor axial bone metastases. Smoking cessation and limited alcohol consumption are commonly recommended lifestyle measures in patients receiving ADT. Contemporary guidelines regarding lifestyle modifications vary by country, organization, and expert opinion. This comprehensive review will provide an evidence-based, updated summary of lifestyle interventions that could be implemented to preserve bone health and maintain quality-of-life throughout the disease course of PCa.

Exercise and Nutritional Approaches to Combat Cancer-Related Bone and Muscle Loss

PURPOSE OF REVIEW

The aim of this narrative review is to summarise recent literature on the effects of exercise and nutrition interventions alone or in combination on muscle and bone loss in people with cancer.

RECENT FINDINGS

There is emerging evidence to support the inclusion of targeted exercise and nutrition strategies to counter loss of muscle and bone associated with cancer treatments. Although research in this field is advancing, the optimal exercise and nutrition prescription to combat cancer-related bone and muscle loss remain unknown. This review identifies specific components of nutrition and exercise interventions that are promising although require further exploration through studies designed to determine the effect on muscle and bone. A focused research effort is required to elucidate the full potential of exercise and nutrition intervention for people with cancer at risk of bone and muscle loss.

The effectiveness of lifestyle interventions to reduce side effects of androgen deprivation therapy for men with prostate cancer: a systematic review

PURPOSE

The aim of this review is to systematically review randomized controlled trials on lifestyle interventions on PCa patients undergoing androgen deprivation therapy.

METHODS

A literature search was conducted using the electronic databases Medline and PubMed. To be eligible, studies had to be randomized controlled trials (RCTs) that focused on side effects of ADT and lifestyle interventions to reduce side effects for men undergoing ADT with PCa. Lifestyle interventions were defined as interventions that included any dietary or behavioral components.

RESULTS

Twenty-nine trials were included. Most of them focused on exercise interventions, while some investigated the effect of dietary or behavioral interventions. The effect of different lifestyle influencing modalities aimed to improve on the adverse effects of ADT varied greatly.

CONCLUSIONS

It is not possible to draw one conclusion on the effect of exercise-based interventions, but noted on several adverse effects of ADT improvement. Further studies are necessary to develop personalized lifestyle interventions in order to mitigate the adverse effects.

Bone Health in Men with Prostate Cancer: Review Article

PURPOSE OF REVIEW

The improvement in prostate cancer survival over time, even in those with advanced disease, has led to an increasing recognition of the impact of prostate cancer and its treatment on bone health. Cancer treatment-induced bone loss (CTIBL) is a well-recognized entity but greater awareness of the risks associated with CTIBL and its treatment is required.

RECENT FINDINGS

The principal culprit in causing CTIBL is hormonal ablation induced by prostate cancer treatment, including several new agents which have been developed in recent years which significantly improve survival, but may cause CTIBL. This review discusses the impact of prostate cancer and its treatment on bone health, including published evidence on the underlying pathophysiology, assessment of bone health, and strategies for prevention and treatment. It is important to recognize the potential cumulative impact of systemic prostate cancer treatments on bone health.

Management of Osteoporosis in Survivors of Adult Cancers With Nonmetastatic Disease: ASCO Clinical Practice Guideline

PURPOSE

The aim of this work is to provide evidence-based guidance on the management of osteoporosis in survivors of adult cancer.

METHODS

ASCO convened a multidisciplinary Expert Panel to develop guideline recommendations based on a systematic review of the literature.

RESULTS

The literature search of the 2018 systematic review by the US Preventive Services Task Force in the noncancer population was used as the evidentiary base upon which the Expert Panel based many of its recommendations. A total of 61 additional studies on topics and populations not covered in the US Preventive Services Task Force review were also included. Patients with cancer with metastatic disease and cancer survival outcomes related to bone-modifying agents are not included in this guideline.

RECOMMENDATIONS

Patients with nonmetastatic cancer may be at risk for osteoporotic fractures due to baseline risks or due to the added risks that are associated with their cancer therapy. Clinicians are advised to assess fracture risk using established tools. For those patients with substantial risk of osteoporotic fracture, the clinician should obtain a bone mineral density test. The bone health of all patients may benefit from optimizing nutrition, exercise, and lifestyle. When a pharmacologic agent is indicated, bisphosphonates or denosumab at osteoporosis-indicated dosages are the preferred interventions.

Epidemiology of Prostate Cancer

Prostate cancer is the second most frequent cancer diagnosis made in men and the fifth leading cause of death worldwide. Prostate cancer may be asymptomatic at the early stage and often has an indolent course that may require only active surveillance. Based on GLOBOCAN 2018 estimates, 1,276,106 new cases of prostate cancer were reported worldwide in 2018, with higher prevalence in the developed countries. Differences in the incidence rates worldwide reflect differences in the use of diagnostic testing. Prostate cancer incidence and mortality rates are strongly related to the age with the highest incidence being seen in elderly men (> 65 years of age). African-American men have the highest incidence rates and more aggressive type of prostate cancer compared to White men. There is no evidence yet on how to prevent prostate cancer; however, it is possible to lower the risk by limiting high-fat foods, increasing the intake of vegetables and fruits and performing more exercise. Screening is highly recommended at age 45 for men with familial history and African-American men. Up-to-date statistics on prostate cancer occurrence and outcomes along with a better understanding of the etiology and causative risk factors are essential for the primary prevention of this disease.

Cancer- and Chemotherapy-Induced Musculoskeletal Degradation

Mobility in advanced cancer patients is a major health care concern and is often lost in advanced metastatic cancers. Erosion of mobility is a major component in determining quality of life but also starts a process of loss of muscle and bone mass that further devastates patients. In addition, treatment options become limited in these advanced cancer patients. Loss of bone and muscle occurs concomitantly. Advanced cancers that are metastatic to bone often lead to bone loss (osteolytic lesions) but may also lead to abnormal deposition of new bone (osteoblastic lesions). However, in both cases there is a disruption to normal bone remodeling and radiologic evidence of bone loss. Many antitumor therapies can also lead to loss of bone in cancer survivors. Bone loss releases cytokines (TGFβ) stored in the mineralized matrix that can act on skeletal muscle and lead to weakness. Likewise, loss of skeletal muscle mass leads to reduced bone mass and quality via mechanical and endocrine signals. Collectively these interactions are termed bone-muscle cross-talk, which has garnered much attention recently as a prime target for musculoskeletal health. Pharmacological approaches as well as nutrition and exercise can improve muscle and bone but have fallen short in the context of advanced cancers and cachexia. This review highlights our current knowledge of these interventions and discusses the difficulties in treating severe musculoskeletal deficits with the emphasis on improving not only bone mass and muscle size but also functional outcomes. © 2019 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

Extracellular Vesicles in the Adaptive Process of Prostate Cancer during Inhibition of Androgen Receptor Signaling by Enzalutamide

Current treatments for advanced prostate cancer focus on inhibition of the androgen receptor (AR) by androgen deprivation therapy (ADT). However, complex interactions mediated by tumor suppressors, oncogenes, aberrations of AR expression, or de novo androgen production have been shown to induce the adaptive response of prostate cancer, leading to the development of castration resistant prostate cancer. In this study, we report the effects of AR antagonist, enzalutamide on the protein contents of extracellular vesicles (EVs). EVs mediate cell-to-cell communication and increasing evidence shows the role of EVs in promoting cancer survival and metastasis. We found that treatment with enzalutamide alters the secretion of EVs, one of which is a plasma membrane calcium pump, ATP2B1/PMCA ATPase, as an AR-regulated EV protein. We highlight the networks of interactions between AR, Ca²⁺ , and ATP2B1, where the extracellular proteins thrombospondin-1, gelsolin, and integrinß1 were previously reported as regulators for cancer progression and metastasis, indicating the potential role of EV-derived proteins in mediating calcium homoeostasis under AR inhibition by enzalutamide. Our data further highlight the cross-talk between AR signaling and EV pathways in mediating resistance toward ADT.

Signaling regulation and role of filamin A cleavage in Ca2+-stimulated migration of androgen receptor-deficient prostate cancer cells

Ca²⁺, a ubiquitous cellular signal, and filamin A, an actin-binding protein, play an important role in the regulation of cell adhesion, shape and motility. Using transwell filters to analyze cell migration, we found that extracellular Ca²⁺ (Ca_o²⁺) promotes the migration of androgen receptor (AR)-deficient and highly metastatic prostate cancer cell lines (DU145 and PC-3) compared to AR-positive and relatively less metastatic prostate cancer cells (LNCaP). Furthermore, we found that expression of filamin A is up-regulated in DU145 and PC-3 cells, and that Ca_o²⁺ significantly induces the cleavage of filamin A. Silencing expression of Ca²⁺-sensing receptor (CaR) and p115RhoGEF, and treating with leupeptin, a protease inhibitor, and ALLM, a calpain specific inhibitor, we further demonstrate that Ca_o²⁺-induced filamin A cleavage occurs via a CaR- p115RhoGEF-calpain dependent pathway. Our data show that Ca_o²⁺ via CaR- mediated signaling induces filamin A cleavage and promotes the migration in AR-deficient and highly metastatic prostate cancer cells.

Cancer Treatment and Bone Health

Considerable advances in oncology over recent decades have led to improved survival, while raising concerns about long-term consequences of anticancer treatments. In patients with breast or prostate malignancies, bone health is a major issue due to the high risk of bone metastases and the frequent prolonged use of hormone therapies that alter physiological bone turnover, leading to increased fracture risk. Thus, the onset of cancer treatment-induced bone loss (CTIBL) should be considered by clinicians and recent guidelines should be routinely applied to these patients. In particular, baseline and periodic follow-up evaluations of bone health parameters enable the identification of patients at high risk of osteoporosis and fractures, which can be prevented by the use of bone-targeting agents (BTAs), calcium and vitamin D supplementation and modifications of lifestyle. This review will focus upon the pathophysiology of breast and prostate cancer treatment-induced bone loss and the most recent evidence about effective preventive and therapeutic strategies.

Improving bone health in men with prostate cancer receiving androgen deprivation therapy: Results of a randomized phase 2 trial

BACKGROUND

Strategies to improve bone health care in men receiving androgen deprivation therapy (ADT) are not consistently implemented. The authors conducted a phase 2 randomized controlled trial of 2 education-based models-of-care interventions to determine their feasibility and ability to improve bone health care.

METHODS

A single-center parallel-group randomized controlled trial of men with prostate cancer who were receiving ADT was performed. Participants were randomized 1:1:1 to 1) a patient bone health pamphlet and brief recommendations for their family physician (BHP+FP); 2) a BHP and support from a bone health care coordinator (BHP+BHCC); or 3) usual care. The primary efficacy outcome was receipt of a bone mineral density (BMD) test within 6 months. Secondary efficacy outcomes included guideline-appropriate calcium and vitamin D use and bisphosphonate prescriptions for men at high fracture risk. Feasibility endpoints included recruitment, retention, satisfaction, contamination, and outcome capture. The main analysis used logistic regression with a 1-sided P of .10. The trial is registered at ClinicalTrials.gov (identifier NCT02043236).

RESULTS

A total of 119 men were recruited. The BHP+BHCC strategy was associated with a greater percentage of men undergoing a BMD test compared with the usual-care group (78% vs 36%; P<.001). BMD ordering also was found to be increased with the BHP+FP strategy (58% vs 36%; P = .047). Both strategies were associated with higher percentages of patients using calcium and vitamin D, but only the BHP+FP arm was statistically significant (P = .039). No men were detected to be at high fracture risk. All but one feasibility endpoint was met.

CONCLUSIONS

Educational strategies to improve bone health care appear feasible and are associated with improved BMD ordering in men receiving ADT. Cancer 2018;124:1132-40. © 2017 American Cancer Society.

Efficacy of a multi-component exercise programme and nutritional supplementation on musculoskeletal health in men treated with androgen deprivation therapy for prostate cancer (IMPACT): study protocol of a randomised controlled trial

Background

Prostate cancer is the most commonly diagnosed cancer in men in developed countries. Androgen deprivation therapy (ADT) is a systemic treatment shown to increase survival in selected patients with prostate cancer. The use of ADT continues to increase for all stages and grades of prostate cancer despite known treatment-induced adverse effects. The primary aim of this study is to examine the efficacy of a targeted, multi-component resistance and impact-loading exercise programme together with a daily protein-, calcium- and vitamin D-enriched supplement on bone health in men treated with ADT for prostate cancer. Secondary aims are to determine the effects of this intervention on measures of total body and regional body composition, cardiometabolic risk, inflammatory markers, health-related quality of life and cognitive function.

Methods

This study is a two-arm randomised controlled trial. Men currently treated with ADT for prostate cancer will be randomised to either a 52-week, community-based, exercise training and nutritional supplementation intervention (n = 51) or usual care control (n = 51). Participants will be assessed at baseline, 26 weeks and 52 weeks for all measures. The primary outcome measures are proximal femur and lumbar spine areal bone mineral density (BMD). Secondary outcomes comprise: changes in tibial and radial bone structure and strength, total body and regional body composition, muscle strength and function, as well as cardiometabolic health, catabolic/inflammatory and anabolic/anti-inflammatory cytokines, health-related quality of life and cognitive function.

Discussion

This study investigates whether a multi-component intervention incorporating a targeted bone and muscle-loading programme in combination with a protein-, calcium- and vitamin D-enriched supplement can ameliorate multiple adverse effects of ADT when compared to usual care. The results will contribute to the development of exercise training and nutrition guidelines for optimising overall health in men treated with ADT for prostate cancer.

Trial registration

Australia New Zealand Clinical Trial Registry (ANZCTR), ID: ACTRN12614000317695. Registered on 25 march 2014.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2185-z) contains supplementary material, which is available to authorized users.

Treatment of Metastatic Prostate Cancer in Older Adults

The aging of the population, along with rising life expectancy, means that increasing numbers of older men will be diagnosed with prostate cancer, and a large proportion of these men will present with metastatic disease. In this paper, we discuss recent advances in prostate cancer treatment. In particular, we review management approaches for older patients with metastatic prostate cancer based on the decision tree developed by the International Society of Geriatric Oncology, which categorized older men as "fit," "vulnerable," and "frail" according to comprehensive geriatric assessment.

Food Fortification and Supplement Use-Are There Health Implications?

Dietary supplements are a multi-billion dollar industry in the U.S., and their use is increasing exponentially. Additionally, many foods and beverages are increasingly being fortified with single or multiple vitamins and minerals. Consequently, nutrient intakes are exceeding the safe limits established by the Institute of Medicine. In this paper, we examine the benefits and drawbacks of vitamin and mineral supplements and increasing consumption of fortified foods (in addition to dietary intake) in the U.S.

POPULATION

The pros and cons are illustrated using population estimates of folic acid, calcium, and vitamin D intake, highlighting concerns related to overconsumption of nutrients that should be addressed by regulatory agencies.

Lifestyle guidelines for managing adverse effects on bone health and body composition in men treated with androgen deprivation therapy for prostate cancer: an update

Background:

Men treated with androgen deprivation therapy (ADT) for prostate cancer are prone to multiple treatment-induced adverse effects, particularly with regard to a deterioration in bone health and altered body composition including decreased lean tissue mass and increased fat mass. These alterations may partially explain the marked increased risk in osteoporosis, falls, fracture and cardiometabolic risk that has been observed in this population.

Methods:

A review was conducted that assessed standard clinical guidelines for the management of ADT-induced adverse effects on bone health and body composition in men with prostate cancer.

Results:

Currently, standard clinical guidelines exist for the management of various bone and metabolic ADT-induced adverse effects in men with prostate cancer. However, an evaluation of the effectiveness of these guidelines into routine practice revealed that men continued to experience increased central adiposity, and, unless pharmacotherapy was instituted, accelerated bone loss and worsening glycaemia occurred.

Conclusions:

This review discusses the current guidelines and some of the limitations, and proposes new recommendations based on emerging evidence regarding the efficacy of lifestyle interventions, particularly with regard to exercise and nutritional factors, to manage ADT-related adverse effects on bone health and body composition in men with prostate cancer.

Integrating diet and exercise into care of prostate cancer patients on androgen deprivation therapy

Improved diagnosis and treatment regimens have resulted in greater longevity for men with prostate cancer. This has led to an increase in both androgen deprivation therapy (ADT) use and duration of exposure, and therefore to its associated adverse effects, such as sexual dysfunction, osteoporosis, reduced muscle mass, increased fat mass, and increased incidence of cardiovascular disease and type 2 diabetes. Given that the adverse effects of ADT are systemic, often debilitating, and difficult to treat, efforts continue in the development of new strategies for long-term management of prostate cancer. The PubMed database was searched to select trials, reviews, and meta-analyses in English using such search terms as "prostate cancer" and "androgen deprivation therapy", "cardiovascular risk", "lean body mass", "exercise", and "diet". The initial searches produced 379 articles with dates 2005 or more recent. Articles published after 2004 were favored. This review utilizes the latest data to provide a status update on the effects of exercise and diet on patients with prostate cancer, focusing on ADT-associated side effects, and it discusses the evidence for such interventions. Since the evidence of large-scale trials in patients with prostate cancer is missing, and an extrapolation of supporting data to all patient subgroups cannot be provided, individualized risk assessments remain necessary before the initiation of exercise and diet programs. Exercise, diet, and nutritional supplementation interventions have the potential to provide effective, accessible, and relatively inexpensive strategies for mitigating ADT-associated toxicities without introducing additional adverse effects.

Common medications and prostate cancer mortality: a review

PURPOSE

Most prostate cancer patients also have comorbidities that are treated with both prescription and nonprescription medications; furthermore, many use dietary supplements. We assess their association with prognosis after prostate cancer diagnosis, and we discuss methodological challenges and clinical implications.

METHODS

We reviewed high-quality observational studies investigating the association of commonly used medications and supplements with prostate cancer-specific mortality.

RESULTS

There is preliminary evidence that statins and metformin use may be associated with lower risk of cancer-specific mortality after prostate cancer diagnosis; conversely, high calcium and multivitamin supplementation may be associated with increased risk. Evidence is inconclusive for nonsteroidal anti-inflammatory drugs, acetylsalicylic acid (aspirin), insulin, antihypertensives such as angiotensin-converting enzyme inhibitors and beta-blockers, digoxin, and warfarin. Common limitations of the internal validity of studies examined include unmeasured confounding and confounding by indication, competing risks, and time-related biases such as immortal time bias. The majority of studies focused on Caucasian men with specific comorbidities, while heterogeneity among patients and tumors was mostly not assessed.

CONCLUSIONS

Commonly prescribed medications and over-the-counter supplements may influence prognosis among prostate cancer patients. Further well-designed pharmacoepidemiologic studies and randomized controlled trials of selected medications in appropriate patient groups are necessary before these drugs can bear new indications for prostate cancer treatment. We discuss considerations when deciding about use of these drugs in clinical practice at the present time.

Quality of care provided to prostate cancer (PC) patients for prevention and treatment of osteoporosis induced by androgen deprivation therapy (ADT)

OBJECTIVES

This study aims to evaluate the quality of care (QOC) and use of validated risk algorithms provided in a specialized osteoporosis clinic to men with prostate cancer on androgen deprivation therapy (ADT) who are at risk of bone loss and fragility fractures.

PATIENTS AND METHODS

Charts for 100 consecutive men (mean age 73.0 years) on ADT referred to a tertiary osteoporosis clinic in Toronto, Canada between 2010 and 2014 were reviewed. The following QOC issues were examined: (a) bone health services provided, i.e., screening, preventing, and treating osteoporosis; and (b) use of national guidelines and fracture risk assessment tools for targeting appropriate therapy.

RESULTS

The median (IQR) duration of ADT was 21.4 (26.9) months at the baseline visit. Nineteen patients had their first bone mineral density test before starting ADT and 34 during the first year of use. At initial consultation, 83 and 30 patients were taking inadequate amounts of calcium and vitamin D, respectively. A validated fracture risk assessment tool was used in all patients; 42 had a moderate 10-year fracture risk and 12 were high risk. Sixteen (72.7 %) of sedentary patients were advised to increase physical activity. Sixty-four (77.1 %) and 28 (93.3 %) of patients not taking appropriate amounts of calcium and vitamin D, respectively, were recommended to adjust their intake to guideline levels. All patients at high fracture risk were recommended a bisphosphonate.

CONCLUSIONS

The majority of referred patients had moderate to high fracture risk. The osteoporosis clinic recommended guideline-based bone health care for the vast majority of men on ADT.

Italian association of clinical endocrinologists (AME) position statement: drug therapy of osteoporosis

Treatment of osteoporosis is aimed to prevent fragility fractures and to stabilize or increase bone mineral density. Several drugs with different efficacy and safety profiles are available. The long-term therapeutic strategy should be planned, and the initial treatment should be selected according to the individual site-specific fracture risk and the need to give the maximal protection when the fracture risk is highest (i.e. in the late life). The present consensus focused on the strategies for the treatment of postmenopausal osteoporosis taking into consideration all the drugs available for this purpose. A short revision of the literature about treatment of secondary osteoporosis due both to androgen deprivation therapy for prostate cancer and to aromatase inhibitors for breast cancer was also performed. Also premenopausal females and males with osteoporosis are frequently seen in endocrine settings. Finally particular attention was paid to the tailoring of treatment as well as to its duration.

The association between regular use of aspirin and the prevalence of prostate cancer: Results from the National Health Interview Survey

Prostate cancer is prevalent with significant morbidity in the United States. Aspirin previously has been found to be associated with reduced carcinogenesis of prostate cells. However, it remains unclear whether regularly taking aspirin could lower the risk of prostate cancer. Therefore, our aim was to examine the association between self-reported regular use of aspirin and the prevalence of prostate cancer in a national sample of the US adult population.The National Health Interview Survey is an annual survey conducted by the National Center for Health Statistics to investigate health and healthcare use of the US population. The current study is a population-based cross-sectional study using the 2010 National Health Interview Survey data. Adult male respondents who self-reported regularly taking aspirin at least 3 times per week were grouped as regular users. The prostate cancer prevalence was measured by respondents' self-report of prostate cancer. Multivariable logistic regression models were used to evaluate the association between these 2 factors by adjusting for covariates selected based on Andersen Behavioral Model of Health Services Use.An estimated 23 million (23.7%) males in the United States reported that they took aspirin regularly. Of them, 5.0% had prostate cancer. Regular aspirin use was significantly associated with a lower self-reported prevalence of prostate cancer after adjusting for predisposing, enabling, and need factors (odds ratio 0.60, 95% confidence interval 0.38-0.94).Regular aspirin use was found to be significantly associated with a lower self-reported prevalence of prostate cancer in the United States in 2010. Further clinical trials and longitudinal studies are needed to confirm the causality between regular aspirin use and prostate cancer.

Vitamin D in Prostate Cancer

Metastatic castration-resistant prostate cancer (mCRPC) is a progressive, noncurable disease induced by androgen receptor (AR) upon its activation by tumor tissue androgen, which is generated from adrenal steroid dehydroepiandrosterone (DHEA) through intracrine androgen biosynthesis. Inhibition of mCRPC and early-stage, androgen-dependent prostate cancer by calcitriol, the bioactive vitamin D3 metabolite, is amply documented in cell culture and animal studies. However, clinical trials of calcitriol or synthetic analogs are inconclusive, although encouraging results have recently emerged from pilot studies showing efficacy of a safe-dose vitamin D3 supplementation in reducing tumor tissue inflammation and progression of low-grade prostate cancer. Vitamin D-mediated inhibition of normal and malignant prostate cells is caused by diverse mechanisms including G1/S cell cycle arrest, apoptosis, prodifferentiation gene expression changes, and suppressed angiogenesis and cell migration. Biological effects of vitamin D are mediated by altered expression of a gene network regulated by the vitamin D receptor (VDR), which is a multidomain, ligand-inducible transcription factor similar to AR and other nuclear receptors. AR-VDR cross talk modulates androgen metabolism in prostate cancer cells. Androgen inhibits vitamin D-mediated induction of CYP24A1, the calcitriol-degrading enzyme, while vitamin D promotes androgen inactivation by inducing phase I monooxygenases (e.g., CYP3A4) and phase II transferases (e.g., SULT2B1b, a DHEA-sulfotransferase). CYP3A4 and SULT2B1b levels are markedly reduced and CYP24A1 is overexpressed in advanced prostate cancer. In future trials, combining low-calcemic, potent next-generation calcitriol analogs with CYP24A1 inhibition or androgen supplementation, or cancer stem cell suppression by a phytonutrient such as sulfarophane, may prove fruitful in prostate cancer prevention and treatment.

Nutritional supplements and cancer: potential benefits and proven harms

Nutritional supplements are widely used among patients with cancer who perceive them to be anticancer and antitoxicity agents. Large-scale, randomized cancer prevention trials have mainly been negative, with some notable adverse and beneficial effects. For example, these trials showed that beta-carotene increases the risk of lung and stomach cancer, vitamin E increases prostate cancer and colorectal adenoma, and selenium reduces gastric and lung cancer in populations with low selenium levels but increase rates in those with higher levels. Both beta-carotene and vitamin E supplementation increase overall mortality. This article reviews phase II and III trials that examine the effects of multivitamins, antioxidants, vitamin D, and n-3 supplements on outcome and toxicity from cancer treatments. Although vitamin E and beta-carotene reduce toxicity from radiotherapy among patients with head and neck cancer, it has been found to increase recurrence, especially among smokers. Antioxidants have mixed effects on chemotherapy toxicity, but there are no data on outcome. Vitamin D deficiency is relatively common among patients with cancer, and ongoing phase III trials are studying the effect of vitamin D on outcome as well as optimum vitamin D and calcium intakes for bone health. Docosahexanoic and eicosopentanoic acid supplements have mixed effects on cachexia and are currently being tested as potential adjuncts to maximize response to chemotherapy. Nutritional supplementation tailored to an individual's background diet, genetics, tumor histology, and treatments may yield benefits in subsets of patients. Clinicians should have an open dialogue with patients about nutritional supplements. Supplement advice needs to be individualized and come from a credible source, and it is best communicated by the physician.

Androgen-deprivation-associated bone disease

PURPOSE OF REVIEW

Androgen deprivation therapy (ADT) remains a common treatment for prostate cancer, even in the nonmetastatic setting and in scenarios without evidence of efficacy. Increasing attention has focused on its adverse effects, of which bone disease in the form of osteoporosis and fractures has been one of the major concerns. Recently published articles are reviewed, focusing on ADT effects on bone and management of ADT-associated bone disease.

RECENT FINDINGS

A range of strategies directed at ADT-associated bone disease are available, including antiresorptive agents such as denosumab and bisphosphonates, as well as complementary approaches such as calcium and vitamin D supplementation, exercise regimens, and multifaceted interventions incorporating several approaches. Most interventions used bone mineral density as a surrogate outcome, despite compelling evidence that it inadequately captures fracture risk.

SUMMARY

The antiresorptive agents are clearly able to preserve bone mineral density in men on ADT, whereas other approaches have modest to no benefits. Unfortunately, despite intense research interest in this area, no approach has yet demonstrated a definitive and convincing reduction in clinically relevant fracture outcomes. This emphasizes the importance of restricting the use of ADT to settings in which its benefits are clearly established, in order to limit unnecessary complications.

Functional and metabolic complications of androgen deprivation therapy

Prostate cancer is the most common non-cutaneous cancer in men worldwide. Several different treatment strategies are available including minimally invasive procedures for localized tumors such as radical prostatectomy, radiotherapy, and androgen deprivation therapy, among others. All these strategies can be given as mono-therapy or as combination therapy. For this review, we will focus on the side effects of androgen deprivation therapy, independent of the other treatment modalities. Some of the most common affections are loss of bone mineral density, weight gain and obesity, myocardial infarction and sudden death, metabolic syndrome and insulin resistance, dyslipidemia, loss of libido and erectile dysfunction, fatigue, cognitive decline, vasomotor flushing, to mention a few. All these alterations can have an impact on quality of life and even lead to more serious complications such as fractures and cardiovascular complications. We present recommendations for prevention, early recognition and treatment. The different modalities for androgen deprivation therapy have particular side-effects profiles and indications should be made in an individualized manner. Androgen deprivation therapy is a useful tool for some patients with prostate cancer but every effort should be made to avoid related complications. The use of guidelines and educational programs for both, patients and urologists, are extremely useful strategies.

The use of dietary supplements to alleviate androgen deprivation therapy side effects during prostate cancer treatment

Prostate cancer (PCa), the most commonly diagnosed cancer and second leading cause of male cancer death in Western societies, is typically androgen-dependent, a characteristic that underlies the rationale of androgen deprivation therapy (ADT). Approximately 90% of patients initially respond to ADT strategies, however many experience side effects including hot flashes, cardiotoxicity, metabolic and musculoskeletal alterations. This review summarizes pre-clinical and clinical studies investigating the ability of dietary supplements to alleviate adverse effects arising from ADT. In particular, we focus on herbal compounds, phytoestrogens, selenium (Se), fatty acids (FA), calcium, and Vitamins D and E. Indeed, there is some evidence that calcium and Vitamin D can prevent the development of osteoporosis during ADT. On the other hand, caution should be taken with the antioxidants Se and Vitamin E until the basis underlying their respective association with type 2 diabetes mellitus and PCa tumor development has been clarified. However, many other promising supplements have not yet been subjected large-scale clinical trials making it difficult to assess their efficacy. Given the demographic trend of increased PCa diagnoses and dependence on ADT as a major therapeutic strategy, further studies are required to objectively evaluate these supplements as adjuvant for PCa patients receiving ADT.

Adverse effects of androgen deprivation therapy and strategies to mitigate them

CONTEXT

Androgen-deprivation therapy (ADT) is a key component of treatment for aggressive and advanced prostate cancer, but it has also been associated with adverse effects on bone, metabolic, cardiovascular, sexual, and cognitive health as well as body composition.

OBJECTIVE

To review the current literature on the adverse effects of ADT and strategies for ameliorating harm from ADT.

EVIDENCE ACQUISITION

The Medline database (through PubMed) was searched from inception to August 1, 2013, for studies documenting the side effects of ADT and for randomized and prospective trials of interventions to mitigate those side effects.

EVIDENCE SYNTHESIS

Adverse effects of ADT include decreases in bone mineral density; metabolic changes such as weight gain, decreased muscle mass, and increased insulin resistance; decreased libido and sexual dysfunction; hot flashes; gynecomastia; reduced testicle size; anemia; and fatigue. Several observational studies suggest an increased risk of diabetes and cardiovascular events, although most published studies report that ADT is not linked to greater cardiovascular mortality. Randomized trials have found value in treatments for some adverse effects including bone loss (bisphosphonates, denosumab, selective estrogen receptor modulators), markers of metabolic syndrome (exercise, diet, metformin), gynecomastia (tamoxifen, prophylactic radiation), muscle loss (resistance and aerobic exercise), and hot flashes (venlafaxine, medroxyprogesterone, cyproterone acetate, gabapentin).

CONCLUSIONS

ADT is often a necessary component of the treatment of aggressive prostate cancer, yet it has known harms that can impair health and quality of life. Clinicians should be aware of interventions that can help mitigate these adverse effects.

PATIENT SUMMARY

Androgen deprivation therapy is a critical component of the management of aggressive and advanced prostate cancer, but it causes adverse effects including bone loss, metabolic changes, gynecomastia, muscle loss, hot flashes, and possibly increased cardiovascular events. Clinicians should be aware of interventions that can help mitigate these adverse effects.

Optimal pharmacotherapeutic management of hormone-sensitive metastatic prostate cancer

The mainstay of initial therapy of metastatic prostate cancer has not changed since 1941 when Huggins and Hodges described the efficacy of castration. The benefit of combining an androgen receptor blocker with medical castration has been debatable despite several large randomized trials and meta-analyses intended to answer the question. Recent phase III trial data with continuous versus intermittent androgen deprivation in newly diagnosed metastatic prostate cancer have established continuous therapy as the preferred approach at the present time. Novel and more potent inhibitors of androgen signaling have been developed in the past 5 years and have been validated in castration-resistant disease. Their role in management of hormone-sensitive metastatic prostate cancer is under evaluation in ongoing studies. As androgen deprivation therapy carries significant long-term toxicities including fatigue and loss of bone and muscle mass, an important element of clinical management is prevention and amelioration of these toxicities.

Cholesterol-induced activation of TRPM7 regulates cell proliferation, migration, and viability of human prostate cells

Cholesterol has been shown to promote cell proliferation/migration in many cells; however the mechanism(s) have not yet been fully identified. Here we demonstrate that cholesterol increases Ca(2+) entry via the TRPM7 channel, which promoted proliferation of prostate cells by inducing the activation of the AKT and/or the ERK pathway. Additionally, cholesterol mediated Ca(2+) entry induced calpain activity that showed a decrease in E-cadherin expression, which together could lead to migration of prostate cancer cells. An overexpression of TRPM7 significantly facilitated cholesterol dependent Ca(2+) entry, cell proliferation and tumor growth. Whereas, TRPM7 silencing or inhibition of cholesterol synthesis by statin showed a significant decrease in cholesterol-mediated activation of TRPM7, cell proliferation, and migration of prostate cancer cells. Consistent with these results, statin intake was inversely correlated with prostate cancer patients and increase in TRPM7 expression was observed in samples obtained from prostate cancer patients. Altogether, we provide evidence that cholesterol-mediated activation of TRPM7 is important for prostate cancer and have identified that TRPM7 could be essential for initiation and/or progression of prostate cancer.

Changes in bone mineral density in men starting androgen deprivation therapy and the protective role of vitamin D

SUMMARY

Androgen deprivation therapy in 80 men was associated with declines in bone mineral density (BMD), which were greatest in the first year, and in the lumbar spine compared to controls. Vitamin D use was associated with improved BMD in the lumbar spine and in the first year.

INTRODUCTION

Decreased BMD is a common side effect of androgen deprivation therapy (ADT), leading to increased risk of fractures. Although loss of BMD appears to be greatest within the first year of starting ADT, there are few long-term studies of change in BMD, and risk factors for bone loss are not well-characterized.

METHODS

Men aged 50+ with nonmetastatic prostate cancer starting continuous ADT were enrolled in a prospective longitudinal study. BMD was determined by dual-energy x-ray absorptiometry at baseline and yearly for 3 years. Matched controls were men with prostate cancer not receiving ADT. Multivariable regression analysis examined predictors of BMD loss.

RESULTS

Eighty ADT users and 80 controls were enrolled (mean age 69 years); 52.5 % had osteopenia and 8.1 % had osteoporosis at baseline. After 1 year, in adjusted models, ADT was associated with significant losses in lumbar spine BMD compared to controls (-2.57 %, p = 0.006), with a trend towards greater declines at the total hip (p = 0.09). BMD changes in years 2 and 3 were much smaller and not statistically different from controls. Use of vitamin D but not calcium was associated with improved BMD in the lumbar spine in year 1 (+6.19 %, p < 0.001) with smaller nonsignificant increases at other sites (+0.86 % femoral neck, +0.86 % total hip, p > 0.10) primarily in the first year.

CONCLUSIONS

Loss of BMD associated with ADT is greatest at the lumbar spine and in the first year. Vitamin D but not calcium may be protective particularly in the first year of ADT use.

Osteoporosis and cancer

Cancer is a major risk factor for bone loss and fractures. This is due both to direct effects of cancer cells on the skeleton and to deleterious effects of cancer-specific therapies on bone cells. Marked improvements in survival for many cancers mean that strategies to limit bone loss and reduce fracture risk must be incorporated into the care plans for nearly all patients with cancer. The vast majority of effort thus far has focused on bone loss in patients with breast and prostate cancers, with comparatively few studies in other malignancies. Antiresorptive therapies have proven nearly universally effective for limiting bone loss in cancer patients, although few studies have been powered sufficiently to include fractures as primary endpoints, and patients are frequently neither identified nor treated according to published guidelines. Nonpharmacologic approaches to limit falls, particularly in elderly patients, are also likely important adjunctive measures for most cancer patients.

Calcium and vitamin D supplementation and loss of bone mineral density in women undergoing breast cancer therapy

An unintended consequence of breast cancer therapies is an increased risk of osteoporosis due to accelerated bone loss. We conducted a systematic review of calcium and/or vitamin D (Ca±D) supplementation trials for maintaining bone mineral density (BMD) in women with breast cancer using the "before-after" data from the Ca±D supplemented comparison group of trials evaluating the effect of drugs such as bisphosphonates on BMD. Whether Ca±D supplements increase BMD in women undergoing breast cancer therapy has never been tested against an unsupplemented control group. However, results from 16 trials indicate that the Ca±D doses tested (500-1500mg calcium; 200-1000IU vitamin D) were inadequate to prevent BMD loss in these women. Cardiovascular disease is the main cause of mortality in women with breast cancer. Because calcium supplements may increase cardiovascular disease risk, future trials should evaluate the safety and efficacy of Ca±D supplementation in women undergoing breast cancer therapy.

Castration-resistant prostate cancer: AUA Guideline

PURPOSE

This Guideline is intended to provide a rational basis for the management of patients with castration-resistant prostate cancer based on currently available published data.

MATERIALS AND METHODS

A systematic review and meta-analysis of the published literature was conducted using controlled vocabulary supplemented with keywords relating to the relevant concepts of prostate cancer and castration resistance. The search strategy was developed and executed by reference librarians and methodologists to create an evidence report limited to English-language, published peer-reviewed literature. This review yielded 303 articles published from 1996 through 2013 that were used to form a majority of the guideline statements. Clinical Principles and Expert Opinions were used for guideline statements lacking sufficient evidence-based data.

RESULTS

Guideline statements were created to inform clinicians on the appropriate use of observation, androgen-deprivation and antiandrogen therapy, androgen synthesis inhibitors, immunotherapy, radionuclide therapy, systemic chemotherapy, palliative care and bone health. These were based on six index patients developed to represent the most common scenarios encountered in clinical practice.

CONCLUSIONS

As a direct result of the significant increase in FDA-approved therapeutic agents for use in patients with metastatic CRPC, clinicians are challenged with a multitude of treatment options and potential sequencing of these agents that, consequently, make clinical decision-making more complex. Given the rapidly evolving nature of this field, this guideline should be used in conjunction with recent systematic literature reviews and an understanding of the individual patient's treatment goals. In all cases, patients' preferences and personal goals should be considered when choosing management strategies.

Vitamin d levels in subjects with prostate cancer compared to age-matched controls

Prostate cancer (PCa) is the second most common cancer in men worldwide and the second leading cause of cancer deaths in men in the United States. Vitamin D is considered to have anticancer properties, currently thought to work mainly through its nuclear receptor or vitamin D receptor. In this retrospective study, we compared vitamin D levels in subjects with PCa with those of age-matched men without PCa. Study subjects included 479 in each group with a mean age of 73 and a mean creatinine of 1.05 and 1.15. Levels of 25 (OH) vitamin D were 28.4 ± 0.54 and 28.05 ± 0.62 in subjects with and without PCa. Levels of 1,25 (OH) vitamin D were 47.2 ± 6.8 and 47.1 ± 7.11 in subjects with and without PCa. In contrast to other studies, we did not find a significant difference in vitamin D levels. Among prostate cancer patients, vitamin D levels correlated positively with age (r = 0.12, P < 0.02), and were negatively associated with BMI (r = -0.13, P = 0.003), glucose (r = -0.12, P < 0.007), HbA1C (r = -0.16, P = 0.001), and PTH (r = -0.21; P < 0.0001). The data do not show the causal effect of vitamin D levels on PCa.