Introduction: Skeletal-related events (SRE) are associated with poor survival and quality-of-life in patients with castrate-resistant prostate cancer (CRPC). The objective of this study is to identify early risk factors for SRE in a contemporary-treated cohort of CRPC patients.

Methods: Patients diagnosed with CRPC at our institution from 2012 to 2019 were retrospectively reviewed. All patients were managed by a dedicated uro-oncologist. The primary outcome was the first occurrence of an SRE, defined as radiographic evidence of pathologic fracture, spinal cord compression, or need for bone radiotherapy. A multivariable Cox model was used to identify the strongest predictors of time to SRE.

Results: A total of 230 patients were included in our study (Table 1). Median follow-up was 17.6 months (interquartile range 8.7-32.3 months), during which 107 patients (47%) developed SREs. On multivariable analysis, presence of metastases at diagnosis (HR 3.587), higher PSA (HR 1.001), LDH (HR 1.001), and ALP (HR 1.001) were associated with increased risk of SREs. The area under the curve (AUC) for this model was 0.70.

Conclusions: We identified several clinical and biochemical predictors available at CRPC diagnosis that are associated with increased risk of SREs. A high degree of clinical scrutiny is warranted in such patients, and early bone directed therapies should be instituted. This work supports earlier introduction of androgen receptor axis therapies to delay the progression to mCRPC and to improve quality of life.