Long-Term Changes In Bone Mineral Density And Predicted Fracture Risk In Patients Receiving Androgen-Deprivation Therapy For Prostate Cancer

Main Category: Prostate / Prostate Cancer
Also Included In: Urology / Nephrology;  Bones / Orthopaedics;  Cancer / Oncology
Article Date: 26 May 2009 - 2:00 PST

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UroToday.com - In the online edition of the British Journal of Urology International, Dr. Vivek Wadhwa and colleagues report on the relationship between androgen deprivation therapy (ADT) and changes in bone mineral density (BMD). Skeletal-related fractures are more common due to osteoporosis rather than cancer in men with metastatic prostate cancer (CaP). The authors point out that measurement of BMD predicts fracture risk as accurately as blood pressure predicts stroke. Their goal was to study the long-term effects of LHRH agonist and antiandrogen therapy on BMD of selected groups of men with newly diagnosed advanced CaP, stratified by BMD at presentation and to predict alterations in fracture risk.

The study cohort consisted of 618 men at a single institution recruited and followed from 1999 to 2007. Clinical and pathologic characteristics were assessed. The BMD was measured prior to ADT using a DEXA scan. Osteoporosis was defined as a BMD of <-2.5 SD below the mean, osteopenia between -1.0 and -2.5, and a normal BMD defined as >-1. DEXA was repeated annually. Participants with osteoporosis were begun on 150mg bicalutamide daily, and osteopenics and normal BMD patients began an LHRH agonist. Vitamin D and calcium were given to osteoporotic and osteopenic men. Oral bisphosphonates were given per primary physician discretion.

Mean patient age was 73, and 41% of men at diagnosis were osteoporotic, 39% were osteopenic and 20% had normal BMD. Other clinical variables were similar among these three groups. Fractures were related to BMD, being 7% in those with normal BMD, 18% with osteopenia and 26% in men with osteoporosis. Vertebral fractures also increased with increasing age; 7% in men <60 years, 11% ages 60-69, 19% ages 70-79, and 24% age >80 years. There were significant reductions in BMD from baseline in normal and osteopenic men, but no significant change in the osteoporotic men. Among osteopenic men at baseline, 35% progressed to osteoporosis after 1 year and 60% after 2 years of treatment with an LHRH agonist. Overall, 39% of men died during the study period of which 47% were from CaP.

These data demonstrate that a significant proportion of men requiring ADT already have osteoporosis or osteopenia and vertebral fractures. LHRH agonist therapy caused significant and sustained reductions in BMD, while men in bicalutamide maintained BMD.

Wadhwa VK, Weston R, Mistry R, Parr NJ
BJU Int. 2009 Mar 10. Epub ahead of print.
doi: 10.1111/j.1464-410X.2009.08483.x

Written by UroToday.com Contributing Editor Christopher P. Evans, MD, FACS

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