Eight studies (571,594 participants) were included in the review, which contained 210,772 screening participants and 360,822 control participants. Seven of these studies were randomised controlled trials (426,337 participants). Total sample sizes ranged from 9,026 to 162,243; number of participants per screening arm ranged from 1,494 to 72,890; number of participants per control (non-screening) arm ranged from 7,532 to 133,287.
Compared to control groups, screened groups had a statistically significantly higher risk of being diagnosed with prostate cancer (RR 1.55, 95% CI 1.17 to 2.06, Ι²=99%, seven trials), and a significantly higher risk of prostate cancer tumours being diagnosed as localised (RR 1.81, 95% CI 1.15 to 2.86, Ι²=99%, four trials). The risk of having a diagnosis of metastatic prostate cancer was lower in screened groups versus control groups but was not statistically significant (RR 0.63, 95% CI 0.38 to 1.05, Ι²=88%, six trials).
Compared to control groups, screened groups had a statistically significantly higher risk of being diagnosed with a low-grade prostate cancer tumour (RR 2.32, 95% CI 1.39 to 3.88, Ι²=99%, six trials). The risk of being diagnosed with a high-grade prostate cancer tumour was lower in screened groups versus controls; this difference was not statistically significant (RR 0.91, 95% CI 0.73 to 1.14, Ι²=76%, six trials).
The risk of prostate cancer mortality was lower in screened groups versus control groups but was not statistically significant (RR 0.88, 95% CI 0.72 to 1.06, Ι²=65%, seven trials). Following exclusion of trials meeting specific criteria recorded at the data extraction stage, the risk of prostate cancer mortality was statistically significantly lower in screening groups compared with control groups (RR 0.76, 95% CI 0.58 to 0.98, Ι²=66%, four trials).
Differences in all-cause mortality were not statistically significant.