Clinical studies are now always able to demonstrate a beneficial effect of lycopene on the progression of prostate cancer. One phase II clinical study did not show the protective effect of lycopene on prostate cancer. Jatoi and his co-workers administered lycopene (30 mg daily) to 46 patients with androgen-independent prostate cancer. Only one patient showed a significant decline in serum prostate-specific antigen level. They also found that lycopene was well tolerated [1]. Another study by the Fred Hutchinson Cancer Research Center was also no able to show a link between lycopene and prostate cancer. They even found that a high intake of beta-carotene actually increased the risk of aggressive prostate cancer [3]. Or should lycopene be consumed together with green tea in order to be effective? A study by the Curtin University of Technology, Australia, showed that lycopene had a stronger protective effect with people who also consumed green tea. This case-control study compared the intake of tea and lycopene of 130 prostate cancer patients with that of 274 healthy controls. Both the intake of lycopene rich foods and green tea showed a protective effect against prostate cancer but the intake of both products was synergistic. A Dutch study conducted at the Erasmus Medical Centre showed that lycopene or vitamin E alone was not able to significantly reduced prostate tumor volume of rats with intraprostatic tumor injection. However, a combined treatment with lycopene and vitamin E suppressed
prostate cancer growth by 73% and increased survival from 47 to 66 days. The study concluded that "lycopene combined with vitamin E may inhibit the growth of prostate cancer" [4].
A large prospective study by the National Cancer Institute (USA) showed little evidence that the consumption of tomato products protects from prostate cancer. The study only found a protective effect of the consumption of some tomato products in individuals with a family history of prostate cancer. This study involved more than 29,000 which were followed during a period of 4 years [5]. A clinical trial conducted on 71 patients with rising prostate-specific antigen (PSA) levels or with a certain minimum level of PSA showed that lycopene was no able to reduce this level but to stabilize it. This result led the researchers to conclude that lycopene may delay progression of prostate cancer [6]. Another study also showed some positive effect: a study led by Schwarz showed that lycopene inhibited progression of benign prostate hyperplasia of elderly men [2]. Benign prostate hyperplasia refers to the increase in size of the prostate in middle-aged and elderly men. Enlarged prostate leads to symptoms of urinary hesitancy, frequent urination, increased risk of urinary tract infections and urinary retention. It is not considered to be a premalignant lesion but increases the risk of the development of prostate cancer. The study was carried out on 40 males with enlarged prostate but without signs of prostate cancer. Half of the patients received daily 15 mg lycopene for 6 months, after which they were tested for carotenoid status, clinical diagnostic markers of prostate proliferation (such as prostate-specific antigen) and symptoms of prostate enlargement. The results were convincing: lycopene intake stopped the prostate enlargement and decreased the serum level of prostate-specific antigen. The men taking lycopene also showed less typical symptoms of prostate enlargement.
[1] Jatoi A, Burch P, Hillman D, Vanyo JM, Dakhil S, Nikcevich D, Rowland K, Morton R, Flynn PJ, Young C, Tan W A tomato-based, lycopene-containing intervention for androgen-independent prostate cancer: results of a Phase II study from the North Central Cancer Treatment Group." Urology. 2007 Feb;69(2):289-94.
[2] Schwarz S, Obermüller-Jevic UC, Hellmis E, Koch W, Jacobi G, Biesalski HK. "Lycopene inhibits disease progression in patients with benign prostate hyperplasia." J Nutr. 2008 Jan;138(1):49-53.
[3] Peters U, Leitzmann MF, Chatterjee N, Wang Y, Albanes D, Gelmann EP, Friesen MD, Riboli E, Hayes RB. " Serum lycopene, other carotenoids, and prostate cancer risk: a nested case-control study in the prostate, lung, colorectal, and ovarian cancer screening trial." Cancer Epidemiol Biomarkers Prev. 2007 May;16(5):962-8.
[4] Limpens J, Schröder FH, de Ridder CM, Bolder CA, Wildhagen MF, Obermüller-Jevic UC, Krämer K, van Weerden WM. " Combined lycopene and vitamin E treatment suppresses the growth of PC-346C human prostate cancer cells in nude mice." J Nutr. 2006 May;136(5):1287-93.
[5] Kirsh VA, Mayne ST, Peters U, Chatterjee N, Leitzmann MF, Dixon LB, Urban DA, Crawford ED, Hayes RB. " A prospective study of lycopene and tomato product intake and risk of prostate cancer." Cancer Epidemiol Biomarkers Prev. 2006 Jan;15(1):92-8.
[6] Vaishampayan U, Hussain M, Banerjee M, Seren S, Sarkar FH, Fontana J, Forman JD, Cher ML, Powell I, Pontes JE, Kucuk O. "Lycopene and soy isoflavones in the treatment of prostate cancer. " Nutr Cancer. 2007;59(1):1-7.
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