Correlation between Automated Bone Scan Index Change after Cabazitaxel and Survival among Men with Castration-Resistant Prostate Cancer

Abstract

Background: Automated bone scan index (aBSI) change (ΔBSI) after treatment and survival in men with prostate cancer remains unclear. We evaluated the correlation between ΔBSI after cabazitaxel and overall survival (OS) in men with bone metastatic castration-resistant prostate cancer (CRPC). Methods: We retrospectively enrolled 32 men with bone metastatic CRPC who had received cabazitaxel. The correlation between ΔBSI from baseline to 16 weeks after starting cabazitaxel and OS was analyzed by multivariate analysis. Results: Median age and time to CRPC were 70.7 years and 9.5 months, respectively. The median cycles of docetaxel before cabazitaxel were eight. Ten (31.2%) patients had visceral metastases at baseline. Median baseline prostate-specific antigen (PSA) was 123.0 ng/mL. The median aBSIs at baseline and 16 weeks after cabazitaxel were 3.2 and 4.4%, respectively. Improvements in aBSI and PSA after 16 weeks of cabazitaxel occurred in 7 (21.9%) and 12 patients (37.5%), respectively. There were no correlations between ΔBSI and OS (p = 0.55), but PSA change was significantly correlated with OS (p = 0.03) by multivariate analysis. Conclusions: This study demonstrated that ΔBSI from baseline to16 weeks after starting cabazitaxel was not correlated with OS among men with bone metastatic CRPC. Further prospective studies may be warranted to confirm the limited utility of aBSI in this setting.