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| Year : 1996 | Volume
: 12
| Issue : 1 | Page : 56-57 |
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Maximum androgen blockade in advanced prostate cancer : an overview of 22 randomised trials with 3283 deaths in 5710 patients
H SGT Rao
Department of Urology, Sri Venkateswara Institute of Medical Science, Tirupati, India
Correspondence Address:
H SGT Rao
Department of Urology, Sri Venkateswara Institute of Medical Science, Tirupati
India
 Source of Support: None, Conflict of Interest: None  | Check |
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The paucity of consistent, convincing and categorical evidence of an improved survival with Maximum Androgen Blockade (MAB), notwithstanding many randomised trials comparing castration alone versus some form of MAB over one, two (castration combined with anti-androgens, viz., flutamide, cyproterone acetate (CPA), or nilutamide) stimulated the authors to organise a systematic collaborative overview (meta-analysis), of the randomised evidence on MAB in advanced prostate cancer. Overall, 25 properly randomised trials (that began before December, 1989) involving an unconfounded comparison of castration (medical/surgical) alone versus castration and additional treatment with an anti-androgen such as flutamide, cyproterone acetate or nilutamide, were identified. Of these, two were 3-arm trials in which all 3 arms were relevant to the present analysis. Logrank statistics was used which compared the number of deaths observed (O) in the MAB arm with the number of deaths that would have been expected (E) in that arm on the basis of the average pattern of survival in a combination of the 2 treatment arms. The calculations of (E) were stratified for year of death. The statistics (O-E) and its variance (V) were calculated on an intention-to-treat basis. Logrank statistics for each were added together to obtain a total which was used to test the overall effect. 87 percent of these patients had metastases when rando- mised. Follow-up results were not available for 70 patients (1.2 percent). The median follow-up was 40 months, during which 57 percent of patients died. The crude mortality rates were 50 percent for castration alone and 56 percent for MAB. Life-table estimates of the 5-year survival rates were 22.8 percent and 26.2 percent respectively, revealing a non- significant improvement of 3.5 percent. No significant heterogeneity was found between the trials (or between the effects of different types of MAB) and no evidence of any significant additional benefit was found in these MAB trial results (2p greater than 0.1). This study reveals that currently available evidence does not show a longer survival benefit with MAB (cf. conventional castration). |
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