Abstract: PD24-06
Sources of Funding: Northshore University Health System

Introduction

Bone loss and fracture are known risks of androgen-deprivation therapy (ADT), particularly among patients with bone metastases. According to National Comprehensive Cancer Network (NCCN) guidelines, bisphosphonate or denosumab therapy (bone therapy, BT) is indicated for men with metastatic castrate resistant prostate cancer (mCRCP), and should be considered for men with metastatic prostate cancer (mCP) who are at high risk of fracture. We analyzed rates of adherence to these recommendations and factors associated with receiving BT in the Surveillance, Epidemiology, and End Results (SEER) Medicare database.

Methods

Using the 2004-2011 SEER Medicare database, we identified all men older than 65 with mCP, with bone metastases and receiving ADT. We collected their clinical and demographic data, and whether BT was administered. Because our study period preceded the approval of novel agents for mCP and the shift to upfront chemotherapy, we defined castrate resistance as the initiation of chemotherapy. Statistical analysis was performed using SAS v9.3 (Cary, NC).

Results

A total of 2563 men were treated with ADT for mCP, and BT was administered to 431 (16.8%). Utilization of BT increased significantly during the study period, from 5.9% in 2004 to 35.2% in 2011 (p<0.01). On multivariate analysis, men had increased odds of receiving BT if year of diagnosis was later than 2008 or an oncologist was involved in their care, and decreased odds of BT if receiving care in a less urban area (p<0.05, Table 1). Among the subset of men with mCRCP (433, 16.9%), BT was administered to 136 (31.4%). On multivariate analysis, age 80-85 and diagnosis year later than 2010 were associated with increased odds of BT (OR 2.57 and 1.57, respectively; p=0.01). Adverse events related to BT were rare, with osteonecrosis of the jaw occurring in 7 (1.6%) and hypocalcemia in 34 (8.0%).

Conclusions

Utilization of BT among men with mCP is increasing, though the overall usage of these medications remains low. Among men with mCRCP, only 31.4% received bone health treatments in accordance with NCCN guidelines. As novel anti-androgens expand the role of urologists in management of mCRCP, careful consideration of appropriate management of bone health must not be overlooked.

Funding

Northshore University Health System