San Antonio, Texas USA (UroToday.com) Skeletal Related Events (SREs) commonly occur in patients with metastatic castration-resistant prostate cancer (mCRPC) that has spread to the bone. SREs include pathologic fractures, spinal cord compression, radiation to bone for symptoms, or surgery to bone for fractures or symptomatic disease.
While the risk of mCRPC causing SREs is well-established (>90% of patients with mCRPC develop bone metastases), the clinical variables that may predict SREs are not as clear. This multi-institutional group of researchers aimed to identify SRE risk based on commonly measured clinical factors in a cohort of VA patients. They abstracted data from 454 veterans who had mCRPC between 2000-2013, of which 233 (51%) developed bone metastases which were used for multivariable analysis. The primary endpoint was first occurrence of a SRE.
Univariable modeling identified factors that most strongly predicted time to first SRE, and these variables were then included in the multivariable model. At a median follow-up of 7.8 months, 38% of patients had a SRE. Bone pain appeared to be a strong predictor of the presence of SREs; 54% with bone pain vs. 28% without bone pain developed SREs. On multivariable analysis, early metastasis, biopsy Gleason of >=7, radiation as primary localized treatment, and bone pain (HR 3.64) were associated with a higher risk of SREs. The investigators’ findings are clinically significant for several reasons.
The optimal timing of repeat bone imaging in metastatic prostate cancer patients is tricky to define. The authors’ findings suggest that any patient with probable bone pain should be taken seriously, and imaging should be undertaken to discern the presence of a SRE. Furthermore, nearly 40% of patients with mCRPC to bone eventually develop SREs. Note that these patients had already been diagnosed with bony metastasis, and are already known to be at high-risk for SREs. The pharmaceutical space reserved for mCRPC patients with bony metastases is continuing to expand, and the findings in this study suggest that clinicians should be aggressive in preempting the occurrence of SREs with the use of bone-protective agents available on the market. As the authors appropriately conclude, future clinical trials involving a similar cohort of patients should focus both on survival and on reducing SRE risk, since this can greatly impact quality of life and mortality in these men.
Presented By: Zachary Klaassen, Lauren Howard, Amanda de Hoedt, Christopher Amling, William Aronson, Matthew Cooperberg, Christopher Kane, Martha Terris, and Stephen Freedland
Written By: Shreyas Joshi, M.D., Fox Chase Cancer Center
17th Annual Meeting of the Society of Urologic Oncology - November 30 -December 2, 2016 – San Antonio, Texas USA