Bone mineral density in patients with prostate cancer without bone metastases treated with intermittent androgen suppression

Abstract

Objectives To evaluate prospectively the effects of intermittent androgen suppression (AS) on bone mineral density (BMD) in patients with prostate cancer without bone metastases. Methods A total of 19 hormone-naive patients with Stage D0 disease were treated with a luteinizing hormone-releasing hormone analog and an antiandrogen for 9 months, after which AS was discontinued. When the prostate-specific antigen level reached a predetermined threshold, AS was restarted. BMD was measured at baseline, after 9 months of AS, and at the end of the first off-treatment period or at 1 year, whichever occurred first. Results Of the 19 patients, 17 had normal BMD at baseline; 2 patients with osteopenia at baseline were excluded from the analysis. All but 1 of the 17 patients with normal baseline BMD experienced a decline in BMD in the lumbar spine or hip, or both, during AS. After 9 months, the mean BMD in these patients had decreased by 4.5% at the lumbar spine ( P = 0.0007) and by 2.5% at the hip ( P = 0.00013). After a median off-treatment period of 7.9 months, the mean change in BMD of the lumbar spine and hip relative to the post-AS values was 1.5% ( P = 0.06) and −0.01% ( P = 0.09), respectively. Conclusions The observed loss of BMD during 9 months of AS is significantly greater than the expected 0.5% to 1% annual loss. Interruption of AS attenuated the rate of bone loss, although full recovery to the baseline BMD was not achieved in all patients. These data suggest that men treated with AS should undergo baseline and periodic follow-up BMD assessments, because significant bone loss can occur during the first 9 months of AS.