The quality of evidence is downgraded by indirectness (differences in studied patients and patients currently diagnosed with prostate cancer).
A Cochrane review [Abstract] 1 assessed two RCTs involving a total of 837 patients with newly diagnosed prostate cancer. One trial (the VACURG trial, n = 142) was judged to have a high risk of bias and therefore did not provide reliable evidence. The second trial Scandinavian Prostate Cancer Group Study 4 (the SPCG-4, n = 695) was judged to have a low risk of bias.
Baseline characteristics of trial participants in the SPCG-4 were: < 75 years of age; T0d (later changed to T1b) 11.9%, T1c 11.7%, T2 76.1%; Gleason score 2 to 4 13.1%, 5 to 6 47.6%, 7 22.9%, 8 to 10 5.0% and unknown 11.4%.
In the SPCG-4 study mortality from prostate cancer at 12 years was 12.5% in the RP group versus 17.9% in the WW group (RR 0.65, 95% CI 0.45 to 0.94). A subgroup analysis according to age at diagnosis showed a risk difference of 11.2 % in cancer specific mortality for patients < 65 years (RR = 0.50, 95% CI 0.30 to 0.84) and 0.1 % for patients HASH(0x2fcfe80) 65 years (RR = 0.87, 95% CI 0.51 to 1.49) for RP versus WW. In the VACURG trial the overall mortality at 15 years did not differ significantly between the RP and WW groups (HR = 0.9, 95% CI 0.56 to 1.43).
Updated data on the SPCG-4 study was published in NEJM 2. Cumulative prostate-cancer specific mortality at 15 years was significantly lower in the RP group than in the WW group (14.6% and 20.7%, respectively; RR 0.62, 95% CI 0.44 to 0.87). All-cause mortality at 15 years was also lower in the RP group (RR 0.75; 95% CI 0.61 to 0.92).
Clinical comment: The SPCG Study 4 was performed at a time when PSA testing was not routinely performed (only 5.2% had tumors that were detected using screening), and the results may not be applicable to screen-detected cancers.
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