Titration of dosage for the protective effect of zoledronic acid on bone loss in patients submitted to androgen deprivation therapy due to prostate cancer: a prospective open-label study.

BACKGROUND

Bisphosphonates were incorporated as agents for the long-term effect of androgen deprivation therapy (ADT) but no comparative study was established for the optimal schedule for bone preservation.

METHODS

Ninety-five consecutive prostate cancer patients submitted to radical retropubic prostatectomy were recruited. At rising PSA they were prospectively enrolled in nonrandomized fashion and grouped to receive no treatment (21 - control group), and monthly (17), bi-monthly (15), tri-monthly (19) or semestral (15) 4 mg zoledronic acid infusions. The patients were followed to a minimum of 30 months after receiving ADT by LHRH agonists. Bone mineral density (BMD) was measured every 6 months in all 5 studied groups in order to compare the effect of each regimen to nontreatment. Tukey-Kramer and Scheffe's tests were used.

RESULTS

The control group showed an impressive BMD loss throughout the study period. The 4 groups treated with zoledronic acid infusions showed increased BMD in the lumbar area on periodical densitometry and no statistical differences could be established among the 4 studied schedules. Different individual patterns of decreasing (control) or increasing (treated) BMD could be seen along the study as measured by bone densitometry.

CONCLUSIONS

Zoledronic acid treatment promoted effective osseous protection against the natural demineralization process in patients with prostate cancer recurrence submitted to ADT.