Serum Selenium Level and Prostate Cancer: A Case-Control

Study

G.POURMAND, M.D.Professor of Urology,

Urology Research Center,Medical Sciences/University of Tehran

Tehran, IRAN

Background

Essential trace element(1)

Meat, seafood, grains, eggs and etc(1)

Chemo-protective effects(2)

1- Combs GF Jr. 2004, Br J Cancer; Klein EA. 2004, J Urol; Platz EA and Helzlsouer KJ. 2001, Epidemiol Rev. 2- Redman C and Lee S. 1998, Cancer lett; Combs GF Jr. 2005, J Nutr; Kim YS and Milner J. 2001, Nutr Cancer.

• The anti-cancer activity - Inhibiting cellular proliferation - Inducing apoptosis - Facilitating DNA repair by activation of p53 - Disruption of androgen receptor signaling - Glutathione peroxidase

• Redman et al. 1997, Carcinogenesis; Menter et al. 2000, Cancer Epidemiol Biomokers Prev; Seo et al. 2002, PNAS USA; Dong et al. 2003, Cancer Res.

Various parts of the world

Other studies

≠ Other reports

Objective

Does selenium have any effect on Prostate Cancer?

Materials and Methods

• Prospective case-control study• From November 2005 to December 2006• Case group: 62 patients • Control group: 68 consecutive participants

• Exclusion criteria:

Supplementary selenium consumption

Metabolic diseases

Immunodeficiency disorder

Previous intervention on prostate

• Registered characteristics:

- Age - BMI - Smoking - FH of PCa - FFQ - PSA

• Graphite furnace atomic absorption spectrometer

• Statistical analysis: - Categorical: Chi-square test or Fisher’s exact test - Continuous: independent samples t test - Association: Pearson’ s correlation - OR and 95% CI unconditional logistic regression

model - P<0.05

Result

• 130 participants (62 cases and 68 controls)

Comparison of demographic and baseline characteristics of patients in

both groups; (values are mean±SD)

Characteristic Cancer Group (n=62)

Control Group (n=68)

P value

Age (yrs) 70.0±7.6 68.1±8.1 0.17

BMI (kg/m2) 24.2±2.1 24.3±3.0 0.86

Se. Level (μg/L) 66.3±17.7 77.5±22.5 <0.002

FH of PCa 2(3.2%) 1(1.5%) 0.60

Smoking 0.46

Never 45(72.6%) 50(73.5%)

Past 12(19.4%) 9(13.2%)

Current 5(8.1%) 9(13.2%)

PSA (ng/ml) 23.9±25.8 5.7±4.4 <0.001

Characteristic Cancer Group (n=62)

Control Group (n=68)

P value

Tumor Grading -

Low (GS<7) 17(27.4%) -

Intermediate (GS=7) 22(35.5%) -

High (GS>7) 23(37.1%) -

Treatment procedure

Surgery 24(38.7%) -

Hormonal therapy 36(58.1%) -

Radiotherapy 2(3.2%) -

Nutritional selenium consumption

8.54±1.84 8.45±1.78 0.78

Association between age, BMI, smoking, serum selenium level and the risk of prostate cancer

Variable OR 95%CI P value

Age (yrs) 1.037 0.99-1.09 0.134

BMI (kg/m2) 1.000 0.87-1.15 0.999

Smoking habit

Never 1 - -

Former 0.935 0.34-2.26 0.896

Current 0.475 0.14-1.63 0.237

Selenium level (μg/L)

<67.7 1 - -

67.7-89.29 0.478 0.21-1.10 0.084

≥89.3 0.160 0.055-0.470 0.001

Correlation coefficients between serum selenium level and age, BMI, and PSA in controls group

Variable Mean±SD Pearson r P value

Age (yrs) 68.1±8.1 -0.19 0.12

BMI (kg/m2) 24.3±3 -0.03 0.78

PSA (ng/ml) 5.75±4.4 0.03 0.83

Discussion

• Possible inverse association between selenium and PCa

• Agreement studies: ✓Nutritional prevention of cancer (NPC) trial(1)

✓Health professionals follow-up study (HPFS) (2)

✓(Nomura et al. 2000, Cancer Epidemiol Biomarkers Prev) ✓(Brooks et al. 2001, J Urol) ✓(Vogt et al. 2003, Int J Cancer) ✓(Van den Brandt. 2003, Cancer Epidemiol Biomarkers Prev)

✓(Li et al. 2004, J Natl cancer Inst) ✓ 2 recent meta analysis

1- Clark et al 1997, JAMA; Duffield-Lillico 2002, cancer Epidemiol Biomarkers Prev 2- Yoshizawa et al 1998, J Natl Cancer Inst

Disagreement studies:

• Carotene and Retinol Efficacy Trial(1)

• (Lipsky et al. 2004, Urology)• (Allen et al. 2004, Br J Cancer)• (Peters et al. 2007, Am J Clin Nutr)

1- Goodman et al. 2001, Cancer Epidemiol Biomarkers Prev

SELECT Trial Plasma selenium decreases by aging Role in progression Smoking and selenium-prostate cancer association

Conclusion

Our study supports the hypothesis that selenium may protect prostate cancer

Supplementary selenium Selenium-rich foods

Thank you for your time and attention