Nineteen studies were included in the review: six RCTs (n=40 patients,178 men) and 13 observational studies (six cohort studies and seven case control studies, n=840,000 men).
Meta-analysis of the six RCTs showed that there was no statistically significant association between statin use and prostate cancer (RR 1.06, 95% CI 0.93 to 1.20). There was no evidence of statistically significant heterogeneity or of publication bias.
Meta-analysis of 13 observational studies also showed no statistically significant association between statin use and prostate cancer (RR 0.89, 95% CI 0.65 to 1.24). However, there was evidence of statistically significant heterogeneity (I2=98%) and of publication bias (Begg's test p=0.03, Egger's test p=0.08). Further results of subgroup analyses were reported in the review.
There was no statistically significant association between long term use of statin (greater or equal to five years of use) and risk of total prostate cancer (RR 0.93, 95% CI 0.77 to 1.13; six observational studies). However, there was evidence of statistically significant heterogeneity (I2=75%).
There was a statistically significant protective association between statin use and advanced prostate cancer (RR 0.77, 95% CI 0.64 to 0.93; five observational studies), with no evidence of statistically significant heterogeneity or publication bias.