Experimental studies suggest that the risk of prostate cancer is reduced with the intake of long-chain n-3 polyunsaturated fatty acids derived from marine foods, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). However, few human studies have been conducted due to difficulties in assessing the dietary intake of these fatty acids. The authors examined the relationship between prostate cancer risk and EPA and DHA in erythrocyte biomarkers in a population-based case–control study in Auckland, New Zealand during 1996–1997 involving 317 prostate cancer cases and 480 age-matched community controls. Reduced prostate cancer risk was associated with high erythrocyte phosphatidylcholine levels of EPA (multivariate relative risk = 0.59; 95% confidence interval 0.37–0.95, upper vs lowest quartile) and DHA (multivariate relative risk = 0.62; 95% confidence interval 0.39–0.98, upper vs lowest quartile). These analyses support evidence from in vitro experiments for a reduced risk of prostate cancer associated with dietary fish oils, possibly acting via inhibition of arachidonic acid-derived eicosanoid biosynthesis. © 1999 Cancer Research Campaign

Meat doneness and estimated intake of heterocyclic amines from cooked meat were not clearly associated with prostate cancer risk.

This population-based case-control study investigated associations between prostate cancer risk and dietary intake of the carotenoids beta-carotene and lycopene and their major plant food sources, including carrots, green leafy vegetables, and tomato-based foods. The study was carried out in Auckland, New Zealand, during 1996-1997 and recruited 317 prostate cancer cases and 480 controls. The authors found that dietary intake of beta-carotene and its main vegetable sources was largely unassociated with prostate cancer risk, whereas intake of lycopene and tomato-based foods was weakly associated with a reduced risk. These results suggest that in contrast to the findings regarding many types of cancers, vegetables rich in beta-carotene are not protective against prostate cancer. However, lycopene from tomato-based foods was found to be associated with a small reduction in risk.

Experimental studies have suggested that the biosynthesis of arachidonic acid-derived eicosanoids such as prostaglandin E 2 via the cyclo-oxygenase pathway may play a significant role in supporting cell proliferation in human prostate cancer cell lines. However, the aetiological significance of this for clinical prostate cancer has remained unclear. In particular, the potential for prostate cancer chemoprevention using nonsteroidal anti-inflammatory drugs (cyclo-oxygenase inhibitors; NSAIDs) has received little attention. The purpose of our study was to investigate associations between prostate cancer risk and use of NSAIDs. A population-based casecontrol study was carried out over 13 months from 1996 in metropolitan Auckland, New Zealand. A total of 317 newly diagnosed prostate cancer cases (including 192 ''advanced'' cases) representative of all cancer cases in the study population were identified from urology clinic referrals and histology reports. A total of 480 age-matched controls were recruited following random selection from the study population using electoral rolls as the sampling frame. After adjusting for potential confounding by socio-economic status and dietary fat consumption, there was a trend toward reduced risks of advanced prostate cancer associated with regular use of total NSAIDs (RR ‫؍‬ 0.73; 95% CI 0.50-1.07) and total aspirin (RR ‫؍‬ 0.71; 95% CI 0.47-1.08). However, these associations failed to reach statistical significance at the usually accepted levels. Weaker inverse associations were found for total prostate cancers, which included a number of small, low-grade tumours of less clinical significance. These findings lend support to proposed underlying aetiological hypotheses which imply a role for cyclo-oxygenase activity in prostate cancer progression. Int.

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