Ten RCTs (6,555 patients, range 82 to 1,979) were included in the review. Randomisation and allocation concealment were described in six trials. Blinding was used in one trial. Losses to follow-up were described in nine trials. Sample sizes were stated in eight trials. Intention-to-treat analyses were used in six trials. Where stated, trials were either industry-sponsored, publicly funded or used both industry and public funding. The authors reported substantial heterogeneity across the results of the trials for overall survival and presented results from subgroup analyses.
There were statistically significant benefits of androgenic suppressive treatment for overall survival in the subgroups: radiotherapy with goserelin treatment (HR 0.72, 95% CI 0.60 to 0.87; five RCTs; Ι²=50%), central hormone blockage (two studies of goserelin and one study of orchiectomy) (HR 0.61, 95% CI 0.47 to 0.81; three RCTs; Ι²=15%), complete hormonal blockade (HR 0.79, 95% CI 0.69 to 0.90; five RCTs; Ι²=34%), studies of treatment duration six months or less (HR 0.79, 95% CI 0.69 to 0.90; five RCTs; Ι²=34%) and studies with treatment duration of more than one year (HR 0.61, 95% CI 0.47 to 0.81; three RCTs; Ι²=15%). No significant differences in overall survival were observed with orchiectomy and radiotherapy compared to radiotherapy (one RCT) or bicalutamide or estrogenic therapy without luteinising hormone-releasing hormone analogues.
Androgenic suppressive treatment with radiotherapy conferred statistically significant benefits in disease-free survival for each subgroup of treatment modality: goserelin (HR 0.53, 95% CI 0.43 to 0.65; five RCTs; Ι²=74%), goserelin and leuprolide with flutamide (HR 0.48, 95% CI 0.30 to 0.77; two RCTs; Ι²=68%), leuprolide and flutamide (HR 0.55, 95% CI 0.34 to 0.90; one RCT) and bicalutamide (HR 0.61, 95% CI 0.52 to 0.72; one study). Significant benefits in disease-free survival were seen for treatment durations of less than six months (HR 0.57, 95% CI 0.50 to 0.65; six RCTs; Ι²=31%) and of more than one year (HR 0.43, 95% CI 0.38 to 0.50; three RCTs; Ι²=0%).
There was insufficient data to undertake a meta-analysis of adverse events; the authors stated that analyses of individual trials showed no evidence of increased toxicity with androgenic suppressive treatment with or without radiotherapy.
Visual appraisals of funnel plots showed no evidence of publication bias for the primary outcome of overall survival.