“Men with prostate cancer who are initiating ADT have a 5- to 10-fold increased loss of bone density at multiple skeletal sites.” They also lose lean body mass and gain fatty tissue.

Men taking anti-androgen drug therapy to suppress their male hormones are at risk for loss of bone mineral density (BMD) . This puts the men at risk of fractures including of rib, spinal, and/or hip. Until recently, no information was available to patients from the drug manufacturers nor from doctors about how soon after starting after starting on androgen blockade this condition is likely to start.

Some patients and doctors may assume, wrongly, that only very long term use of these drugs is likely to cause osteoporosis.

Dr. Susan L. Greenspan of the University of Pittsburgh and colleagues noticed that although bone loss is associated with androgen deprivvation therapy (ADT), little was known about when this may occur. She designed a study to find out.

She has found that bone turnover leading to loss of bone mineral density can be measured by six months after a man starts androgen suppression.

By 12 months, depending on the site of measurement, BMD loss ranged from 1 to 4 percent in men recently started on ADT.

Healthy controls and men with prostate cancer not receiving ADT had no significant reduction in BMD.

“After 12 months, men receiving acute ADT had a significant reduction in BMD of 2.5 +/- 0.6% at the total hip, 2.4 +/- 1.0% at the trochanter, 2.6 +/- 0.5% at the total radius, 3.3 +/- 0.5% at the total body, and 4.0 +/- 1.5% at the posteroanterior spine.”

Because the rate of bone loss “is maximal in the first year after androgen suppression is initiated,” Greenspan says, drug therapy aimed at stopping the resorption of bone “may be most effective if prescribed during this period.”

Further, “Men receiving acute ADT had a 10.4 +/- 1.7% increase in total body fat and a 3.5 +/- 0.5% reduction in total body lean mass at 12 months.”

Greenspan and her coleagueMartin Resnick MD conclude: “Men with prostate cancer who are initiating ADT have a 5- to 10-fold increased loss of bone density at multiple skeletal sites compared with either healthy controls or men with prostate cancer who are not on ADT, placing them at increased risk of fracture. Bone loss is maximal in the first year after initiation of ADT, suggesting initiation of early preventive therapy.”

Bone loss after initiation of androgen deprivation therapy in patients with prostate cancer.