Prostate cancer prevention

Nixon DW, Zang EA, McShane P, Ferretti A, Ferguson L, Gardnet R. The South Carolina prostate cancer prevention and telehealth program. Controlled Clin Trials 2003 P31. 

Other dietary factors implicated in prostate cancer include retinol, carotenoids, lycopene, and vitamin D consumption.5,6 Retinol, or vitamin A, intake, especially in men older than age 70, is correlated with an increased risk of prostate cancer, whereas intake of its precursor, [3-carotene, has a protective or neutral effect. Lycopene, obtained primarily from tomatoes, decreases the risk of prostate cancer in small cohort studies. The antioxidant vitamin E also may decrease the risk of prostate cancer. Men who developed prostate cancer in one cohort study had lower levels of l,25(OH)2-vitamin D than matched controls, although a prospective study did not support this.2 Clearly, dietary risk factors require further evaluation, but because fat and vitamins are modifiable risk factors, dietary intervention may be promising in prostate cancer prevention. 

Therefore, the use of finasteride to prevent prostate cancer is currently under debate.7 Because of its established benefit in treating BPH, the 20% to 30% of men over age 50 with BPH may derive the additional benefit of prostate cancer prevention and should be offered treatment with finasteride. In the 70% to 80% of men without BPH, the benefits, side effects (primarily impotence), and risks of finasteride should be discussed prior to initiating therapy. 

Finasteride reduces serum prostate-specific antigen concentrations (60). In participants in the Prostate Cancer Prevention Trial who had an end of study biopsy (928... 

Etzioni RD, Howlader N, Shaw PA, Ankerst DP, Penson DF, Goodman PJ, Thompson IM. Long-term effects of finasteride on prostate specific antigen levels results from the prostate cancer prevention trial. J Urol 2005 174(3) 877-81 [erratum 2071]. 

Adhami VM, Ahmad N, Mukhtar H. 2003. Molecular targets for green tea in prostate cancer prevention. J Nutr 133 2417S-2424S. 

Combs GF Status of selenium in prostate cancer prevention. BrJ Cancer 2004 91 195-199. 

Klein, E.A., Thompson, I.M., Lippman, S.M., Goodman, P.J., Albanes, D., Taylor, P.R., and Coltman, C. 2001. SELECT the next prostate cancer prevention trial. Selenum and Vitamin E Cancer Prevention Trial. J. Urol. 166(4), 1311-1315. 

Considerable interest in preventing prostate cancer exists and several large chemoprevention trials are sponsored and ongoing by the National Cancer Institute. The first large chemoprevention trial in prostate cancer, the Prostate Cancer Prevention Trial (PCPT), began in 1993 and randomized 18,881 men older than 55 years with a low risk of prostate cancer (PSA = 3 ng/mL) to receive 5 mg finasteride daily (a 5-a-reductase inhibitor) or placebo to determine if inhibition of DHT synthesis in the prostate for a prolonged period (7 years) would lead to a decreased incidence of prostate cancer. " Finasteride is currently used in the treatment of BPH. 

Marberger M, Adolfsson J, Borkowski A, et al. The clinical implications of the prostate cancer prevention trial. BJU Int 2003 92 667-671. 

Marshall, JR University of Arizona Phase III trial of selenium for prostate cancer prevention CRISP 2001... 

Brawley OW, Parnes H. 2000. Prostate cancer prevention trials in the USA. Eur J Cancer 36 1312-1315. 

Katiyar, S. K. 2006. Matrix metalloproteinase in cancer metastasis Molecular targets for prostate cancer prevention by green tea polyphenols and grape seed proanthocyani-dins. Endocr. Metab. Immune Disord. Drug Target 6 17-24. 

Lycopene (24) is present in prostate tissue. During the last decade the possible role of lycopene (24) in prostate cancer prevention has received much interest [60-62]. 

The 5a-reductase inhibitors have been discussed previously (see Benign Prostatic Hyperplasia results of the Prostate Cancer Prevention Trial (128) for finasteride showed a 25% relative risk reduction in prostate cancer in men aged 55 years or older, albeit at an increased risk of invasive tumors (129). The risk of invasive tumors may outweigh the benefit of these agents. The 5a-reductase inhibitors have not been proven to be effective as chemoprevention against clinically significant prostate cancer. 

National Cancer Institute. The prostate cancer prevention trial. Available at http //www.cancer.gov/pcpt. 

Agarwal R. Cell signaling and regulator of cell cycle as molecular target for prostate cancer prevention by dietary agents. Biochem Pharmacol 2000 60 1051-1059. 

There was neither an additive/synergistic effect of lycopene and vitamin E nor any influence on tumor size. The finding that necrosis rates were enhanced in this model is consistent with observed effects of lycopene on aggressive cancers in humans (see above). A number of in vitro studies showing antiproliferative effects of lycopene in various cancer cell lines [53, 54], including prostate [55, 56] (see below), offer further support for a prostate cancer preventive function. 

Giovannucci, E., Gamma-tocopherol a new player in prostate cancer prevention J. Natl. Cancer Inst. 92 (24), 1966-1967, 2000. 

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