More about NSAIDs and prostate cancer risk. Results in this study are "modest"

http://www.ncbi.nlm.nih.gov/pubmed/21297996

PLoS One. 2011 Jan 28;6(1):e16412.
Use of non-steroidal anti-inflammatory drugs and prostate cancer risk: a population-based nested case-control study.
Mahmud SM, Franco EL, Turner D, Platt RW, Beck P, Skarsgard D, Tonita J, Sharpe C, Aprikian AG.

Department of Oncology, McGill University, Montreal, Canada.
Abstract
BACKGROUND: Despite strong laboratory evidence that non-steroidal anti-inflammatory drugs (NSAIDs) could prevent prostate cancer, epidemiological studies have so far reported conflicting results. Most studies were limited by lack of information on dosage and duration of use of the different classes of NSAIDs.

METHODS: We conducted a nested case-control study using data from Saskatchewan Prescription Drug Plan (SPDP) and Cancer Registry to examine the effects of dose and duration of use of five classes of NSAIDs on prostate cancer risk. Cases (N = 9,007) were men aged ≥40 years diagnosed with prostatic carcinoma between 1985 and 2000, and were matched to four controls on age and duration of SPDP membership. Detailed histories of exposure to prescription NSAIDs and other drugs were obtained from the SPDP.

RESULTS: Any use of propionates (e.g., ibuprofen, naproxen) was associated with a modest reduction in prostate cancer risk (Odds ratio = 0.90; 95%CI 0.84-0.95), whereas use of other NSAIDs was not. In particular, we did not observe the hypothesized inverse association with aspirin use (1.01; 0.95-1.07). There was no clear evidence of dose-response or duration-response relationships for any of the examined NSAID classes.

CONCLUSIONS: Our findings suggest modest benefits of at least some NSAIDs in reducing prostate cancer risk.