Bisphosphonates Can Prevent Skeletal Complications of Malignant Bone Disease from Prostate Cancer and Renal Cell Carcinoma

Abstract

Objectives The majority of patients with hormone-refractory prostate cancer (HRPC) develop bone metastases, which are also common in patients with other genitourinary malignancies. Bone metastases can lead to debilitating skeletal complications and reduced quality of life (QoL). Therefore, the goal of therapy for patients with malignant bone disease is preservation of functional independence and QoL by delaying onset of skeletal-related events (SREs) and by palliating bone pain. Bisphosphonates have become integral in achieving treatment goals for these patients. Methods Data from two phase 3, placebo-controlled trials in patients with malignant bone disease from HRPC or solid tumors including renal cell carcinoma (RCC) were reviewed to determine the efficacy of zoledronic acid in reducing the incidence and delaying the onset of SREs. Results In patients with metastatic HRPC ( n = 422), 4 mg zoledronic acid every 3 wk significantly reduced all types of SREs, delayed time to first SRE by >5 mo, and reduced ongoing risk of SREs by 36% compared with placebo. Moreover, zoledronic acid reduced the risk of experiencing a second SRE compared with placebo and appeared to be more beneficial in patients with no pain at baseline. In a separate trial in patients with solid tumors, zoledronic acid reduced the proportion of patients who experienced any SRE compared with placebo in the RCC subset ( n = 46). Furthermore, zoledronic acid demonstrated trends for longer overall survival in these patient populations. Conclusions Zoledronic acid significantly delays the onset and reduces the incidence of SREs in patients with bone metastases secondary to HRPC and RCC.