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Background: Zinc is involved in many essential cellular functions. It has been shown that the prostate contains high concentrations of zinc, but zinc levels decrease in prostate cancer tissues. Although, experimental evidence implicates zinc in the pathogenesis of prostate cancer, epidemiological data are inconsistent. We conducted a systematic review of the literature to summarize the evidence regarding the association between zinc and prostate cancer. Methods: Relevant studies were identified by searching PubMed and the Cochrane Library databases through November 2012 and reviewing reference lists of retrieved articles. Inclusion criteria were original and peer-reviewed publications reporting the association between zinc intake or status and prostate cancer outcomes (diagnosis, progression). No reviews, editorials, or comments were included. Two investigators abstracted study information and evaluated quality independently using standardized forms. Results: Sixteen studies met inclusion criteria, including 3 cohorts, 2 nested case-control, 10 case-control, and 1 randomized clinical trial, with a total of 111,288 participants and 11,681 cases of prostate cancer. All studies measured the association between zinc levels and prostate cancer. In most studies, regardless of the study design or source of zinc, the highest dose of zinc was associated with a modest elevation of odds of prostate cancer. Four studies had decreased odds of prostate cancer for the highest dose of zinc but the confidence interval crossed one. There was evidence of a dose-response relationship and subgroup analysis revealed a protective effect of high zinc intake among advanced prostate cancer cases. Conclusions: Although the level of zinc in prostate cancer tissue is reduced, studies assessing the association of zinc intake and prostate cancer have yielded inconsistent results. We performed a systematic review to assess the role of zinc in prostate cancer. As a result of this systematic review, the evidence is still insufficient to recommend zinc supplementation for cancer patients in clinical practice. Citation Format: Abeer M. Mahmoud, Umaima Al-alem, Ebony Shah, Ken Batai, Firas Dabbous, Mohamed Ali, Rick Kittles. Zinc and prostate cancer: a systematic review. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4883. doi:10.1158/1538-7445.AM2013-4883

Introduction: Prostate cancer is a solid malignancy that disproportionately affects men of African descent. Zinc, an essential dietary trace mineral, has been implicated in the pathogenesis of prostate cancer. Total zinc intake is lower in older African American men compared to European Americans (NHANES III). Despite the high prevalence of prostate cancer and decreased levels of zinc intake among African Americans, very little is known about the relationship between zinc intake and prostate cancer in this group. This is significant because dietary factors such as zinc intake are potentially modifiable risk factors. Here, we examine the association between self-reported zinc intake and prostate cancer in a hospital-based case-control study. Methods: Newly diagnosed African American men with histologically confirmed prostate cancer (n=141) were recruited from an urban academic urology clinic in Washington, DC. Controls (n=109) were unaffected volunteers. Usual dietary intake was assessed at the time of recruitment (2000 to 2004) with the use of a food-frequency questionnaire. Two tailed T-Test was used to compare characteristic means between cases and controls. Unconditional logistic regression was used to calculate the unadjusted and adjusted odds ratio (OR) and 95% confidence intervals (95%CI). Results: In this population, cases were older and had higher levels of PSA. Controls had higher zinc intake, with a mean of 13.23 mg/day (SD±13.9) versus 10.67 mg/day (SD±7.3) for cases. An increase of 1 mg/day of zinc decreased the odds of prostate cancer by 3% (OR=0.97 and 95% CI: 0.95-1.002). Controlling for age, body mass index (BMI), PSA and total food energy intake did not affect the observed association. Conclusions: Overall, these results suggest that zinc intake may have slight protective effect on prostate cancer. These analyses should be repeated in large studies to confirm these findings. Citation Format: Firas Dabbous, Umaima Al-alem, Sparkle Springfield, Abeer M. Mahmoud, Ken Batai, Ebony Shah, Chiledum Ahaghotu, Rick A. Kittles. Dietary zinc and prostate cancer: a case-control study in African Americans men. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3621. doi:10.1158/1538-7445.AM2013-3621

Introduction and Objective: Obesity/excessive adiposity in men with clinically organ-confined prostate cancer is of growing concern, because it associates with an increased risk of cancer recurrence after definitive therapy based on post-treatment prognostic parameters. The objective of this study was to evaluate whether body weight status associates with pre-treatment predictors of cancer recurrence in this patient population. Methods: We performed a cross-sectional study of body weight status and pre-treatment risk of PSA failure in 119 men awaiting radical prostatectomy for clinically localized prostate cancer in four urologic clinics in the Chicago area. Body weight status was assessed using the body mass index (BMI) and dual-energy x-ray absorptiometry (DXA). D'Amico risk scores, which are based on clinical tumor stage, biopsy Gleason sum, and pre-treatment PSA, were used to rank each patient's 5-year risk of PSA failure as low, intermediate, or high. Ordinal logistical regression analyzed the association between BMI quartile and D'Amico risk scores after accounting for age, race, total grams of body fat, and study site. Results: The risk of PSA failure increased with increasing quartile of BMI. Relative to the lowest BMI quartile, the cumulative odds of an intermediate or higher D'Amico risk score vs. a low risk score (the “cumulative odds ratio”) for patients in the second BMI quartile (mean BMI = 27.8 kg/m2) was 3.51 (95% CI = 1.07 to 11.5, p = .038). For patients in the third quartile (mean BMI = 32.0 kg/m2) and forth quartile (mean BMI = 37.0 kg/m2), the cumulative OR was 6.52 (95% CI = 1.72 to 24.6, p = .0057) and 7.74 (95% CI = 1.18 to 50.9, p = .033), respectively (OR trend = 1.98, 95% CI = 1.09 to 3.59, p = .0254). Conclusions: Body weight status predicts pre-treatment risk of PSA failure in men with clinically localized prostate cancer. This provides further support for a mechanistic link between body weight status, which reflects energy balance, and prostate cancer prognosis. The results also highlight the potential for using body weight status and other lifestyle-related factors pertinent to prostate cancer to identify men who are at high risk for unfavorable treatment outcomes. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4443. doi:1538-7445.AM2012-4443