Cancer Treatment-Induced Bone Loss (CTIBL) in Prostate Cancer: Pathophysiology, Preclinical Findings, and Treatment with Zoledronic Acid

Functional and metabolic complications of androgen deprivation therapy

Prostate cancer is the most common non-cutaneous cancer in men worldwide. Several different treatment strategies are available including minimally invasive procedures for localized tumors such as radical prostatectomy, radiotherapy, and androgen deprivation therapy, among others. All these strategies can be given as mono-therapy or as combination therapy. For this review, we will focus on the side effects of androgen deprivation therapy, independent of the other treatment modalities. Some of the most common affections are loss of bone mineral density, weight gain and obesity, myocardial infarction and sudden death, metabolic syndrome and insulin resistance, dyslipidemia, loss of libido and erectile dysfunction, fatigue, cognitive decline, vasomotor flushing, to mention a few. All these alterations can have an impact on quality of life and even lead to more serious complications such as fractures and cardiovascular complications. We present recommendations for prevention, early recognition and treatment. The different modalities for androgen deprivation therapy have particular side-effects profiles and indications should be made in an individualized manner. Androgen deprivation therapy is a useful tool for some patients with prostate cancer but every effort should be made to avoid related complications. The use of guidelines and educational programs for both, patients and urologists, are extremely useful strategies.

Preventing Bone Loss During Androgen Deprivation Therapy for Prostate Cancer: Early Experience with Neridronate

OBJECTIVE

Androgen-deprivation therapy (ADT) is the usual treatment for locally advanced or metastatic prostate cancer. Osteoporosis is a common complication of ADT. The aim of our study was to evaluate the efficacy of neridronate, a relatively new bisphosphonate to prevent bone loss during androgen ablation.

METHODS

Sixty patients with prostate cancer and osteoporosis were enrolled and randomly assigned to 2 different treatment regimes: group A (30 patients) treated with maximum androgenic blockage (MAB), and group B (30 patients) treated with bicalutamide 150 mg. Each group was divided in 2 subgroups A1-A2 and B1-B2. All patients received calcium and cholecalciferol supplements (500 mg of elemental calcium and 400 IU cholecalciferol) daily. The A2 and B2 subgroups were also treated with neridronate (25 mg intramuscular monthly). Lumbar and femoral bone mineral density (BMD) was evaluated by dualenergy X-ray absorptiometry (DXA), both at baseline and after one year of treatment. Deoxypyridinoline (DPD) and bone-alkaline phosphatase (B-ALP) were determined at the beginning, midstudy and at the end.

RESULTS

Patients treated only with calcium and cholecalciferol (A1, B1 subgroups) showed a marked bone loss after 6, and 12 months, with increased levels of DPD and BALP, compared to baseline values. Patients treated with neridronate (A2 et B2 subgroups) showed unchanged levels of these markers. After one year of treatment, lumbar and total hip BMD decreased significantly in patients treated only with calcium and cholecalciferol (A1 subgroup: -4.9% and -1.9% respectively). BMD did not change significantly at any site in patients treated also with neridronate (A2 subgroup: +1% and +0.8% respectively). Lumbar and total hip BMD did not change significantly (-1.5% and -1% respectively) in B1 subgroup. In B2 subgroup an important increase in lumbar spine and the total hip BMD was shown (+2.5% and 1.6% respectively). No relevant side effects were recorded during our study.

CONCLUSION

In conclusion, neridronate is an effective and safe treatment in preventing bone loss in men receiving ADT for prostate cancer.