192 Background: Bone is a common site of metastatic involvement in patients (pts) with prostate cancer (PC). Bony metastases (mets) are associated with skeletal complications, which can cause significant morbidity and mortality. Intravenous bisphosphonates (IV BPs) have been proven to reduce the incidence and onset of skeletal complications. Patterns of use of IV BPs in clinical practice in pts with bone mets due to PC are largely unknown. Methods: Using the tumor registries and electronic data stores at two large US integrated health systems that serve a total of approximately 1.3 million persons, we retrospectively identified all pts aged ≥18 yrs with primary PC and newly diagnosed bone mets between 1/1/95 and 12/31/09. Information on all administrations of IV BPs between date of diagnosis of bone mets and death, loss to follow-up, or end of study was extracted from administrative data stores and electronic medical records, which also were reviewed by trained medical abstractors for evidence of skeletal-related events (SREs) (spinal cord compression, pathologic fracture, surgery to bone, radiation to bone). Results: We identified a total of 461 pts with primary PC and newly diagnosed bone mets. Mean (SD) age was 72.8 yrs (10.7 yrs); 75% were Caucasian, and 21% were African-American. Median duration of follow-up after diagnosis of bone mets was 1.3 yrs. One-fifth (20.2%) of study subjects received IV BPs (92% zoledronic acid, 8% pamidronate) during follow-up--10.8% prior to, and 9.3% after, first on-study SRE. Median time from diagnosis of bone mets to first administration of IV BPs was 1.7 yrs, and the median number of administrations was 3. The percentage of study subjects receiving IV BPs increased steadily over the 15-yr study period--from 7.5% among those newly diagnosed with bone mets in 1995-1999, to 19.8% among those newly diagnosed with bone mets in 2000-2004, to 27.5% among those newly diagnosed with bone mets in 2005-2009. Conclusions: Despite a high risk of SREs in pts with PC and bone mets, most such pts still do not receive IV BPs.
Utilization of intravenous bisphosphonates in patients with bone metastases secondary to breast, lung, or prostate cancer