A Cochrane review [Abstract] 1 included 5 studies with a total of 1382 subjects. All the included studies involved advanced (T3 or T4) prostate cancer. None of the studies assessed disease-specific survival or metastatic disease. One study (N = 77) evaluated biochemical outcomes. A subgroup analysis found no significant differences in biochemical progression (defined by the authors as PSA≥ 10 ng/mL) between intermittent androgen suppression (IAS) and continuous androgen suppression (CAS) for Gleason scores 4 - 6, 7, and 8 - 10. For patients with a Gleason score > 6, reduction in biochemical progression favoured the IAS group (RR 0.10, 95% CI 0.01 to 0.67, P = 0.02). Studies primarily reported on adverse events. One trial (N = 43) found no difference in adverse effects (gastrointestinal, gynecomastia and asthenia) between IAS (2 events) and CAS (5 events), with the exception of impotence, which was significantly lower in the IAS group (RR 0.72, 95% CI 0.56 to 0.92, P = 0.008).
Comment:The quality of evidence is downgraded by study quality (unclear allocation concealment, intention-to-treat adherence not reported), by indirectness (short study duration and no data for survival or disease progression) and by imprecise results (limited study size for each comparison).
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