Diet and survival after prostate cancer diagnosis

Perceiving a need for dietary change in adults living with and beyond cancer: A cross-sectional study

BACKGROUND

Many people living with and beyond cancer (LWBC) do not meet dietary recommendations. To implement a healthier diet, people LWBC must perceive a need to improve their diet.

METHODS

Participants included people diagnosed with breast, prostate or colorectal cancer in the UK. Two binary logistic regression models were conducted with perceived need for dietary change as the outcome (need to improve vs. no need). Predictor variables included demographic and clinical characteristics, receipt of dietary advice, and either body mass index (BMI) or adherence to seven relevant World Cancer Research Fund (WCRF) dietary recommendations.

RESULTS

The sample included 5835 responses. Only 31% perceived a need to improve their diet. Being younger (odds ratio [OR] 0.95, 95% confidence interval [CI] = 94-0.95), female (OR = 1.33, 95% CI = 1.15-1.53), not of white ethnicity (OR = 1.8, 95% CI = 1.48-2.27), not married/cohabiting (OR = 1.32, 95% CI = 1.16-1.52) and having received dietary advice (OR = 1.36, 95% CI = 1.43-1.86) was associated with an increased odds of perceiving a need to improve diet. This association was also seen for participants with two or more comorbidities (OR = 1.31, 95% CI = 1.09-1.57), those not meeting the recommendations for fruit and vegetables (OR = 0.47, 95% CI = 0.41-0.55), fat (OR = 0.67, 95% CI = 0.58-0.77), and sugar (OR = 0.86, 95% CI = 0.75-0.98) in the dietary components model and those who had a higher BMI (OR = 1.53, 95% CI = 1.32-1.77) in the BMI model.

CONCLUSIONS

Most of this sample of people LWBC did not perceive a need to improve their diet. More research is needed to understand the reasons for this and to target these reasons in dietary interventions.

Nutrition and dietary restrictions in cancer prevention

The composition and pattern of dietary intake have emerged as key factors influencing aging, regeneration, and consequently, healthspan and lifespan. Cancer is one of the major diseases more tightly linked with aging, and age-related mortality. Although the role of nutrition in cancer incidence is generally well established, we are far from a consensus on how diet influences tumour development in different tissues. In this review, we will discuss how diet and dietary restrictions affect cancer risk and the molecular mechanisms potentially responsible for their effects. We will cover calorie restriction, intermittent fasting, prolonged fasting, fasting-mimicking diet, time-restricted eating, ketogenic diet, high protein diet, Mediterranean diet, and the vegan and vegetarian diets.

Possible Biochemical Processes Underlying the Positive Health Effects of Plant-Based Diets-A Narrative Review

Plant-based diets are becoming more popular for many reasons, and epidemiological as well as clinical data also suggest that a well-balanced vegan diet can be adopted for the prevention, and in some cases, in the treatment of many diseases. In this narrative review, we provide an overview of the relationships between these diets and various conditions and their potential biochemical background. As whole plant foods are very rich in food-derived antioxidants and other phytochemicals, they have many positive physiological effects on different aspects of health. In the background of the beneficial health effects, several biochemical processes could stand, including the reduced formation of trimethylamine oxide (TMAO) or decreased serum insulin-like growth factor 1 (IGF-1) levels and altered signaling pathways such as mechanistic target of rapamycin (mTOR). In addition, the composition of plant-based diets may play a role in preventing lipotoxicity, avoiding N-glycolylneuraminic acid (Neu5Gc), and reducing foodborne endotoxin intake. In this article, we attempt to draw attention to the growing knowledge about these diets and provide starting points for further research.

New Insights Into the Mechanism of COP9 Signalosome-Cullin-RING Ubiquitin-Ligase Pathway Deregulation in Urological Cancers

Urological cancers are a very common type of cancer worldwide and have alarming high incidence and mortality rates, especially in kidney cancers, illustrate the urgent need for new therapeutic targets. Recent publications point to a deregulated COP9 signalosome (CSN)-cullin-RING ubiquitin-ligase (CRL) pathway which is here considered and investigated as potential target in urological cancers with strong focus on renal cell carcinomas (RCC). The CSN forms supercomplexes with CRLs in order to preserve protein homeostasis and was found deregulated in several cancer types. Examination of selected CSN-CRL pathway components in RCC patient samples and four RCC cell lines revealed an interesting deregulated p27(Kip1)-Skp2-CAND1 axis and two p27(Kip1) point mutations in 786-O cells; p27(Kip1)V109G and p27(Kip1)I119T. The p27(Kip1) mutants were detected in patients with RCC and appear to be responsible for an accelerated growth rate in 786-O cells. The occurrence of p27(Kip1)V109G and p27(Kip1)I119T in RCC makes the CSN-CRL pathway an attractive therapeutic target.

[Cancer and life style: What really helps?]

The continuously growing number of patients who survive cancer (long-term survivors) and their special life situations necessitate an increasing need for consultation on the topics of quality of life and recurrence prophylaxis. This consultation is often associated with aspects of complementary medicine and also social medicine, which are becoming increasingly more important in the long-term care of patients. This article presents the scientifically proven knowledge on the aspects of nutrition, sport, nicotine abuse and professional rehabilitation and their importance for the course of cancer diseases.

Recommendations for Obesity Clinical Trials in Cancer Survivors: American Society of Clinical Oncology Statement

Observational evidence has established a relationship between obesity and cancer risk and outcomes. Interventional studies have demonstrated the feasibility and benefits of lifestyle change after cancer diagnosis, and guidelines recommend weight management and regular physical activity in cancer survivors; however, lifestyle interventions are not a routine part of cancer care. The ASCO Research Summit on Advancing Obesity Clinical Trials in Cancer Survivors sought to identify the knowledge gaps that clinical trials addressing energy balance factors in cancer survivors have not answered and to develop a roadmap for the design and implementation of studies with the potential to generate data that could lead to the evidence-based incorporation of weight management and physical activity programs into standard oncology practice. Recommendations highlight the need for large-scale trials evaluating the impact of energy balance interventions on cancer outcomes, as well as the concurrent conduct of studies focused on dissemination and implementation of interventions in diverse populations of cancer survivors, including answering critical questions about the degree of benefit in key subgroups of survivors. Other considerations include the importance of incorporating economic metrics into energy balance intervention trials, the need to establish intermediate biomarkers, and the importance of integrating traditional and nontraditional funding sources. Establishing lifestyle change after cancer diagnosis as a routine part of cancer care will require a multipronged effort to overcome barriers related to study development, funding, and stakeholder engagement. Given the prevalence of obesity and inactivity in cancer survivors in the United States and elsewhere, energy balance interventions hold the potential to reduce cancer morbidity and mortality in millions of patients, and it is essential that we move forward in determining their role in cancer care with the same care and precision used to test pharmacologic and other interventions.

Nutrient Composition and Anti-inflammatory Potential of a Prescribed Macrobiotic Diet

Despite nutrient adequacy concerns, macrobiotic diets are practiced by many individuals with cancer and other life-threatening illnesses. This study compared the nutrient composition and inflammatory potential of a macrobiotic diet plan with national dietary recommendations and intakes from a nationally representative sample. Nutrient comparisons were made using the 1) macrobiotic diet plan outlined in the Kushi Institute's Way to Health; 2) recommended dietary allowances (RDA); and 3) National Health and Nutrition Examination Survey (NHANES) 2009-2010 data. Comparisons included application of the recently developed dietary inflammatory index (DII). Analyses focused on total calories, macronutrients, 28 micronutrients, and DII scores. Compared to NHANES data, the macrobiotic diet plan had a lower percentage of energy from fat, higher total dietary fiber, and higher amounts of most micronutrients. Nutrients often met or exceeded RDA recommendations, except for vitamin D, vitamin B12, and calcium. Based on DII scores, the macrobiotic diet was more anti-inflammatory compared to NHANES data (average scores of -1.88 and 1.00, respectively). Findings from this analysis of a macrobiotic diet plan indicate the potential for disease prevention and suggest the need for studies of real-world consumption as well as designing, implementing, and testing interventions based on the macrobiotic approach.

Perceived influences on post-diagnostic dietary change among a group of men with prostate cancer

A cancer diagnosis is often associated with loss of agency and control that can adversely affect well-being. Patients may try to regain control through dietary change aimed at preventing progression and/or recurrence. Evidence for the effectiveness of post-diagnostic dietary change in prostate cancer is not conclusive, which can cause uncertainty among patients and health professionals. This qualitative study explored how eight men in the U.K., who had been diagnosed with prostate cancer in the previous 5 years, accounted for any post-diagnostic changes they made to their diet. Data were generated through semi-structured telephone interviews and were subjected to thematic analysis. This yielded two themes concerning the perceived nature and importance of dietary change and the perceived determinants of dietary change. The latter focused on internal dimensions such as agency and external dimensions such as the perceived role of relationships with health professionals, the availability of credible dietary information and family influences. The study points to the importance of the family context in enabling the men to implement dietary change. It is suggested that, even if health professionals can only offer qualified, general advice about diet, this may provide men with a focus for action and a means of regaining control.

Plasma carotenoids and tocopherols in relation to prostate-specific antigen (PSA) levels among men with biochemical recurrence of prostate cancer

BACKGROUND

Although men presenting with clinically localized prostate cancer (PrCA) often are treated with radical prostatectomy or radiation therapy with curative intent, about 25-40% develop biochemically recurrent PrCA within 5 years of treatment, which has no known cure. Studies suggest that carotenoid and tocopherol intake may be associated with PrCA risk and progression. We examined plasma carotenoid and tocopherol levels in relation to prostate-specific antigen (PSA) levels among men with PSA-defined biochemical recurrence of PrCA.

METHODS

Data analyzed were from a 6-month diet, physical activity and stress-reduction intervention trial conducted in South Carolina among biochemically recurrent PrCA patients (n=39). Plasma carotenoids and tocopherol levels were measured using high-performance liquid chromatography (HPLC). Linear regression was used to estimate least-square means comparing PSA levels of men with high versus low carotenoid/tocopherol levels, adjusting for covariates.

RESULTS

After adjusting for baseline PSA level, plasma cis-lutein/zeaxanthin level at 3 months was related inversely to PSA level at 3 months (P=0.0008), while α-tocopherol (P=0.01), β-cryptoxanthin (P=0.01), and all-trans-lycopene (P=0.004) levels at 3 months were related inversely to PSA levels at 6-months. Percent increase in α-tocopherol and trans-β-carotene levels from baseline to month 3 were associated with lower PSA levels at 3 and 6 months. Percent increase in β-cryptoxanthin, cis-lutein/zeaxanthin and all-trans-lycopene were associated with lower PSA levels at 6 months only.

CONCLUSIONS

Certain plasma carotenoids and tocopherols were related inversely to PSA levels at various timepoints, suggesting that greater intake of foods containing these micronutrients might be beneficial to men with PSA-defined PrCA recurrence.

Gender relations and couple negotiations of British men's food practice changes after prostate cancer

Nutrition plays an important role in the health of men diagnosed with prostate cancer and dietary interventions can therefore be a significant part of prostate cancer survivorship supportive care. Family food provision, however, involves complex social interactions, which shape how men engage with their diets and dietary interventions. The role that gender plays in shaping prostate cancer couples' food practices and men's diets after a prostate cancer diagnosis is thought to be important but is little understood. This study explored couples' accounts of nutrition information seeking and diet change to gain a better understanding of how gender relations shaped men's food practices after prostate cancer diagnosis. Qualitative health interviews with men and their partners were conducted and analysed using interpretive descriptive methods. Findings demonstrated how couples navigated food change journeys that involved seeking information, deciding what changes were warranted and implementing and regulating diet changes. Two overarching themes that illustrated couples' food negotiations were called 'Seeking information and deciding on food changes' and 'Monitoring food changes'. Additional sub-themes described who led food changes, women's filtering of information, and moderation or 'treats'. Throughout these food change journeys, interactions between men and women were at play, demonstrating how gender relations and dynamics acted to shape couples' food negotiations and men's food practices. Findings reveal that attention to gender relations and the men's family food dynamics should inform diet interventions for men with prostate cancer in order to improve uptake.

Nutrient intake in the GEICO multicenter trial: the effects of a multicomponent worksite intervention

BACKGROUND/OBJECTIVES

To assess the effects on macro- and micronutrient intake of a nutrition intervention program in corporate settings across the United States.

SUBJECTS/METHODS

Two hundred and ninety-two individuals who were overweight or had type 2 diabetes were recruited from 10 sites of a US insurance company. Two hundred and seventy-one participants completed baseline diet recalls, and 183 participants completed dietary recalls at 18 weeks. Sites were randomly assigned to an intervention group (five sites) or to a control group (five sites) for 18 weeks. At intervention sites, participants were asked to follow a low-fat vegan diet and attend weekly group meetings. At control sites, participants continued their usual diets. At baseline and 18 weeks, participants completed 2-day diet recalls. Between-group differences in changes in nutrient intake were assessed using an analysis of covariance.

RESULTS

Compared with those in the control group, intervention-group participants significantly reduced the reported intake of total fat (P=0.02), saturated (P=0.006) and monounsaturated fats (P=0.01), cholesterol (P=0.009), protein (P=0.03) and calcium (P=0.02), and increased the intake of carbohydrate (P=0.006), fiber (P=0.002), β-carotene (P=0.01), vitamin C (P=0.003), magnesium (P=0.04) and potassium (P=0.002).

CONCLUSIONS

An 18-week intervention program in a corporate setting reduces intake of total fat, saturated fat and cholesterol and increases the intake of protective nutrients, particularly fiber, β-carotene, vitamin C, magnesium and potassium. The reduction in calcium intake indicates the need for planning for this nutrient.

Future prospects in the diagnosis and management of localized prostate cancer

Prostate cancer (PCa) is the commonest visceral cancer in men worldwide. Introduction of serum PSA as a highly specific biomarker for prostatic diseases has led to a dramatic increase in the diagnosis of early stage PCa in last decades. Guidelines underline that benefits as well as risks and squeals of early diagnosis and treatment should be discussed with patients. There are several new biomarkers (Pro-PSA, PCA-3 test, and TMPRSS2-ERG) available on the market but new ones are awaited in order to improve specificity and sensitivity. Investigators have also focused on identifying and isolating the gene, or genes, responsible for PCa. Current definitive treatment options for clinically localized PCa with functional and oncological success rates up to 95% include surgery (radical prostatectomy), external-beam radiation therapy, and interstitial radiation therapy (brachytherapy). Potential complications of overdiagnosis and overtreatment have resulted in arguments about screening and introduced a new management approach called "active surveillance." Improvements in diagnostic techniques, especially multiparametric magnetic resonance imaging, significantly ameliorated the accuracy of tumor localization and local staging. These advances will further support focal therapies as emerging treatment alternatives for localized PCa. As a conclusion, revolutionary changes in the diagnosis and management of PCa are awaited in the near future.

Behavioral stress accelerates prostate cancer development in mice

Prostate cancer patients have increased levels of stress and anxiety. Conversely, men who take beta blockers, which interfere with signaling from the stress hormones adrenaline and noradrenaline, have a lower incidence of prostate cancer; however, the mechanisms underlying stress-prostate cancer interactions are unknown. Here, we report that stress promotes prostate carcinogenesis in mice in an adrenaline-dependent manner. Behavioral stress inhibited apoptosis and delayed prostate tumor involution both in phosphatase and tensin homolog-deficient (PTEN-deficient) prostate cancer xenografts treated with PI3K inhibitor and in prostate tumors of mice with prostate-restricted expression of c-MYC (Hi-Myc mice) subjected to androgen ablation therapy with bicalutamide. Additionally, stress accelerated prostate cancer development in Hi-Myc mice. The effects of stress were prevented by treatment with the selective β2-adrenergic receptor (ADRB2) antagonist ICI118,551 or by inducible expression of PKA inhibitor (PKI) or of BCL2-associated death promoter (BAD) with a mutated PKA phosphorylation site (BADS112A) in xenograft tumors. Effects of stress were also blocked in Hi-Myc mice expressing phosphorylation-deficient BAD (BAD3SA). These results demonstrate interactions between prostate tumors and the psychosocial environment mediated by activation of an adrenaline/ADRB2/PKA/BAD antiapoptotic signaling pathway. Our findings could be used to identify prostate cancer patients who could benefit from stress reduction or from pharmacological inhibition of stress-induced signaling.

Lifestyle factors in cancer survivorship

Lifestyle factors have been linked to the risk of developing many common malignancies and, increasingly, to prognosis. Observational evidence has shown a relationship between so-called energy balance factors (ie, diet, physical activity, and body weight) and risk of cancer recurrence and mortality in cancers of the breast, prostate, colon and, perhaps, other cancers. Interventional work has shown that individuals who make favorable changes in these lifestyle factors after cancer diagnosis feel better, experience less fatigue, and may possibly even decrease risk of cancer recurrence. Other lifestyle behaviors, such as smoking and alcohol consumption, have also been linked to the development of common cancers and may have important health consequences for cancer survivors. This article reviews the evidence that links lifestyle factors to cancer outcomes, provides clinical recommendations for cancer survivors, and describes future directions for lifestyle research in cancer survivors.

The role of obesity in cancer survival and recurrence

Obesity and components of energy imbalance, that is, excessive energy intake and suboptimal levels of physical activity, are established risk factors for cancer incidence. Accumulating evidence suggests that these factors also may be important after the diagnosis of cancer and influence the course of disease, as well as overall health, well-being, and survival. Lifestyle and medical interventions that effectively modify these factors could potentially be harnessed as a means of cancer control. However, for such interventions to be maximally effective and sustainable, broad sweeping scientific discoveries ranging from molecular and cellular advances, to developments in delivering interventions on both individual and societal levels are needed. This review summarizes key discussion topics that were addressed in a recent Institute of Medicine Workshop entitled, "The Role of Obesity in Cancer Survival and Recurrence"; discussions included (i) mechanisms associated with obesity and energy balance that influence cancer progression; (ii) complexities of studying and interpreting energy balance in relation to cancer recurrence and survival; (iii) associations between obesity and cancer risk, recurrence, and mortality; (iv) interventions that promote weight loss, increased physical activity, and negative energy balance as a means of cancer control; and (v) future directions.

Reduced cancer risk in vegetarians: an analysis of recent reports

This report reviews current evidence regarding the relationship between vegetarian eating patterns and cancer risk. Although plant-based diets including vegetarian and vegan diets are generally considered to be cancer protective, very few studies have directly addressed this question. Most large prospective observational studies show that vegetarian diets are at least modestly cancer protective (10%-12% reduction in overall cancer risk) although results for specific cancers are less clear. No long-term randomized clinical trials have been conducted to address this relationship. However, a broad body of evidence links specific plant foods such as fruits and vegetables, plant constituents such as fiber, antioxidants and other phytochemicals, and achieving and maintaining a healthy weight to reduced risk of cancer diagnosis and recurrence. Also, research links the consumption of meat, especially red and processed meats, to increased risk of several types of cancer. Vegetarian and vegan diets increase beneficial plant foods and plant constituents, eliminate the intake of red and processed meat, and aid in achieving and maintaining a healthy weight. The direct and indirect evidence taken together suggests that vegetarian diets are a useful strategy for reducing risk of cancer.

The prognostic role of cancer-specific beliefs among prostate cancer survivors

OBJECTIVE

The objective of this study is to evaluate the association between cancer-specific beliefs and survival among men newly diagnosed with prostate cancer.

METHODS

Based on data from a biracial cohort monitored for mortality for up to 15 years, we investigated the association between beliefs and survival among 251 men newly diagnosed with prostate cancer between 1987 and 1990. We examined patients' beliefs related to efficacy of regular checkups for detection, potential negative treatment effects, and perceived curability of cancer. Cox proportional hazards models were adjusted for sociodemographic variables, medical care measures, clinical factors, and lifestyle.

RESULTS

In a fully adjusted model, not believing that most cancers can be cured was associated with an increased risk of death from any cause (Hazard Ratio = 1.62; 95% confidence interval = 1.11, 2.38). Beliefs regarding the efficacy of checkups or potential negative treatment effects were not associated with survival.

CONCLUSIONS

Prostate cancer patients who reported not believing that most cancers are curable experienced poorer survival after adjusting for a wide array of prognostic factors and potential confounders. Future research to identify underlying behavioral (medical protocol adherence, lifestyle) and physiological (immune and endocrine regulation) mechanisms of this association would translate into improved intervention strategies for cancer survivors.

Men, food, and prostate cancer: gender influences on men's diets

Although healthy eating might enhance long-term survival, few men with prostate cancer make diet changes to advance their well-being. Men's typically poor diets and uninterest in self-health may impede nutrition interventions and diet change. Food choice behavior is complex involving many determinants, including gender, which can shape men's health practices, diets, and prostate cancer experiences. Developing men-centered prostate cancer nutrition interventions to engage men (and where appropriate their partners) in promoting healthy diets can afford health benefits. This article presents an overview and synthesis of current knowledge about men's food practices and provides an analysis of diet and diet change behaviors for men with prostate cancer. Masculinity and gender relations theory are discussed in the context of men's food practices, and suggestions for future applications to nutrition and prostate cancer research and diet interventions are made.

Energetics in colorectal and prostate cancer

For decades, extensive research has explored the association between factors related to energy balance and the development of both colorectal cancer and prostate cancer. Physical inactivity, obesity, higher red meat consumption or Western pattern diet, insulin and insulin-like growth factors (IGFs) appear to increase the risk of colorectal cancer while obesity, high animal fat intake, insulin and IGFs have been associated with increasing prostate cancer risk and/or aggressiveness. Recently, there are growing observational data on the relationship between energetic host factors and progression of these cancers. While there are no large randomized trials in either colorectal cancer or prostate cancer assessing these factors on disease progression or disease-related mortality, the data supporting associations between some of these factors and colorectal or prostate cancer survivorship are getting more compelling. This article will evaluate the emerging data on energy balance in patients with colorectal or prostate cancer.

A worksite programme significantly alters nutrient intakes

Objective

To examine whether a worksite nutrition programme using a low-fat vegan diet could significantly improve nutritional intake.

Design

At two corporate sites of the Government Employees Insurance Company, employees who were either overweight (BMI ≥ 25 kg/m2) and/or had type 2 diabetes participated in a 22-week worksite-based dietary intervention study.

Setting

At the intervention site, participants were asked to follow a low-fat vegan diet and participate in weekly group meetings that included instruction and group support (intervention group). At the control site, participants received no instruction (control group). At weeks 0 and 22, participants completed 3 d dietary records to assess energy and nutrient intake.

Subjects

A total of 109 participants (sixty-five intervention and forty-four control).

Results

In the intervention group, reported intake of total fat, trans fat, saturated fat and cholesterol decreased significantly (P ≤ 0·001), as did energy and protein (P = 0·01), and vitamin B12 (P = 0·002), compared with the control group. Intake (exclusive of any use of nutritional supplements) of carbohydrate, fibre, vitamin C, magnesium and potassium increased significantly (P ≤ 0·0001), as did that for β-carotene (P = 0·0004), total vitamin A activity (P = 0·004), vitamin K (P = 0·01) and sodium (P = 0·04) in the intervention group, compared with the control group.

Conclusions

The present study suggests that a worksite vegan nutrition programme increases intakes of protective nutrients, such as fibre, folate and vitamin C, and decreases intakes of total fat, saturated fat and cholesterol.

Associations between alpha-tocopherol, beta-carotene, and retinol and prostate cancer survival

Previous studies suggest that carotenoids and tocopherols (vitamin E compounds) may be inversely associated with prostate cancer risk, yet little is known about how they affect prostate cancer progression and survival. We investigated whether serum alpha-tocopherol, beta-carotene, and retinol concentrations, or the alpha-tocopherol and beta-carotene trial supplementation, affected survival of men diagnosed with prostate cancer during the alpha-Tocopherol, beta-Carotene Cancer Prevention Study, a randomized, double-blind, placebo-controlled primary prevention trial testing the effects of beta-carotene and alpha-tocopherol supplements on cancer incidence in adult male smokers in southwestern Finland (n = 29,133). Prostate cancer survival was examined using the Kaplan-Meier method with deaths from other causes treated as censoring, and using Cox proportional hazards regression models with hazard ratios (HR) and 95% confidence intervals (CI) adjusted for family history of prostate cancer, age at randomization, benign prostatic hyperplasia, age and stage at diagnosis, height, body mass index, and serum cholesterol. As of April 2005, 1,891 men were diagnosed with prostate cancer and 395 died of their disease. Higher serum alpha-tocopherol at baseline was associated with improved prostate cancer survival (HR, 0.67; 95% CI, 0.45-1.00), especially among cases who had received the alpha-tocopherol intervention of the trial and who were in the highest quintile of alpha-tocopherol at baseline (HR, 0.51; 95% CI, 0.20-0.90) or at the 3-year follow-up measurement (HR, 0.26; 95% CI, 0.09-0.71). Serum beta-carotene, serum retinol, and supplemental beta-carotene had no apparent effects on survival. These findings suggest that higher alpha-tocopherol (and not beta-carotene or retinol) status increases overall prostate cancer survival. Further investigations, possibly including randomized studies, are needed to confirm this observation.

Intake of plant foods and associated nutrients in prostate cancer risk

Plant foods and associated nutrients may impact prostate cancer (PC) risk and survival. Therefore, we compared dietary intake, mainly plant food groups among 382 controls and 478 PC cases (373 incident and 105 prevalent cases). Caucasian controls had significantly higher daily servings of vegetables (3.4 vs. 2.5, P= 0.002) and fruits and/or fruit juices (1.6 vs. 1.3, P = 0.02) compared to African American controls. In Caucasians, incident cases reported lower intake of fiber, vitamin C, vitamin A, alpha -carotene, beta -carotene, cryptoxanthin, folate, genistein, daidzein, and fruits and/or fruit juice than controls and/or prevalent cases. In African Americans, incident cases had lower intake of alpha -carotene compared to controls and prevalent cases. Reduced PC risk was associated with the highest tertile of cryptoxanthin (OR = 0.51; 95% CI = 0.35-0.75), fiber (OR = 0.56; 95% CI = 0.35-0.89), vitamin C (OR = 0.60; 95% CI = 0.41-0.88), and fruits and/or fruit juices (OR = 0.46; 95% CI = 0.31-0.68), with significant linear trends. Increased risk of PC was associated with the highest tertile of protein (OR = 1.99; 95% CI = 1.05-3.79) and daily servings of grains (OR = 1.99; 95% CI = 1.23-3.22) with significant linear trends. In summary, we demonstrate racial/ethnic differences in dietary intake of plant foods. The significantly higher consumption of protective dietary constituents among prevalent cases compared to incident cases suggests that PC survivors may be amenable to dietary change.

Diet and dietary supplement intervention trials for the prevention of prostate cancer recurrence: a review of the randomized controlled trial evidence

PURPOSE

We review the effect of diet and dietary supplement interventions on prostate cancer progression, recurrence and survival.

MATERIALS AND METHODS

A literature search was conducted in MEDLINE, EMBASE and CINAHL to identify diet and dietary supplement intervention studies in men with prostate cancer using prostate specific antigen or prostate specific antigen doubling time as a surrogate serum biomarker of prostate cancer recurrence and/or survival.

RESULTS

Of the 32 studies identified 9 (28%) were randomized controlled trials and the focus of this review. In these studies men had confirmed prostate cancer and elevated or increasing prostate specific antigen. Only 1 trial included men with metastatic disease. When body mass index was reported, men were overweight or obese. A significant decrease in prostate specific antigen was observed in some studies using a low fat vegan diet, soy beverage or lycopene supplement. While not often reported as an end point, a significant increase in prostate specific antigen doubling time was observed in a study on lycopene supplementation. In only 1 randomized controlled trial in men undergoing orchiectomy was a survival end point of fewer deaths with lycopene supplementation reported.

CONCLUSIONS

A limited number of randomized controlled trials were identified in which diet and dietary supplement interventions appeared to slow disease progression in men with prostate cancer, although results vary. Studies were limited by reliance on the surrogate biomarker prostate specific antigen, sample size and study duration. Well designed trials are warranted to expand knowledge, replicate findings and further assess the impact of diet and dietary supplement interventions on recurrence and treatment associated morbidities.