Objective: To evaluate changes in bone mass and fracture risk in patients with prostate cancer on androgen-deprivation therapy (ADT) and with a basal T-score of >-2.0, who were treated with an oral bisphosphonate, as such patients treated with ADT are at increased risk of bone loss and bone fracture.
Patients and methods: We selected 61 patients with prostate cancer treated with ADT; 31 were treated with oral alendronate 70 mg once-weekly and a control group of 30 were not. At baseline and 12 months we measured bone mineral density (BMD) of the lumbar spine, femoral neck and total hip by dual-energy X-ray absorptiometry. All patients had severe osteopenia or osteoporosis at baseline. The risk of femoral neck fracture was calculated at baseline and 12 months (Z-score 2.7).
Results: Patients treated with alendronate had a significant increase in BMD at the lumbar spine and femoral neck after 1 year of follow-up, with mean (sd) values of 1.06 (0.26) vs 1.01 (0.21) g/cm(2) at baseline (P < 0.001), and 0.75 (0.07) vs 0.73 (0.07) g/cm(2) (P = 0.03), respectively, while the control group had a significant loss of BMD at the total hip of 0.79 (0.14) vs 0.81 (0.13) g/cm(2) (P = 0.03). BMD was significantly improved at the three locations in patients treated with alendronate compared with the control group, with differences at the lumbar spine, femoral neck and total hip of 0.05 (0.07) vs 0.01 (0.10) (P = 0.001), 0.01 (0.04) vs -0.002 (0.03) (P = 0.04) and 0.01 (0.04) vs -0.01 (0.02) g/cm(2), respectively (P = 0.001). Patients treated with alendronate had a significant decrease in the fracture risk at the femoral neck, by -0.54 (1.29) (P = 0.04) after 1 year of follow-up.
Conclusions: Treatment with once-weekly 70 mg alendronate significantly improved the BMD at the lumbar spine and femoral neck in patients with prostate cancer with severe osteopenia or osteoporosis and on ADT, and significantly decreased the risk of femoral neck fracture.