Bone Scan Index as a prognostic imaging biomarker during androgen deprivation therapy

Abstract

BackgroundBone Scan Index (BSI) is a quantitative measurement of tumour burden in the skeleton calculated from bone scan images. When analysed at the time of diagnosis, it has been shown to provide prognostic information on survival in men with metastatic prostate cancer (PCa). In this study, we evaluated the prognostic value of BSI during androgen deprivation therapy (ADT).MethodsProstate cancer patients who were at high risk of a poor outcome and who had undergone bone scan at the time of diagnosis and during ADT were recruited from two university hospitals for a retrospective study. BSI at baseline and follow-up were calculated using an automated software package (EXINIbonebsi). Associations between BSI, other prognostic biomarkers and overall survival (OS) were evaluated using a Cox proportional hazards regression model.ResultsOne hundred forty-six PCa patients were included in the study. A total of 102 patient deaths were registered, with a median survival time after the follow-up bone scan of 2.4 years (interquartile range (IQR) =0.8 to 4.4). Both at baseline and during ADT, BSI was significantly associated with OS in univariate and multivariate analyses. When BSI was added to a prognostic base model including age, prostate-specific antigen, clinical tumour stage and Gleason score, the concordance index increased from 0.73 to 0.77 (p =0.0005) at baseline and from 0.77 to 0.82 (p <0.0001) during ADT.ConclusionsAutomated BSI during ADT is an independent prognostic indicator of OS in PCa patients with bone metastasis. It represents an emerging imaging biomarker that can be used in a prognostic model for risk stratification of PCa patients at the time of diagnosis and at later stages of the disease. BSI could then help physicians identify patients who could benefit from more aggressive therapies.

223Ra Therapy of Advanced Metastatic Castration-Resistant Prostate Cancer: Quantitative Assessment of Skeletal Tumor Burden for Prognostication of Clinical Outcome and Hematologic Toxicity

“…We found a significant association between the bone scintigraphy response (according to PCWG2) and OS, although this finding was based on a small number of observations, whereas no association between the BSI response and OS was detected. These results conflict with recent reports of the BSI as a response marker in mCRPC settings (20,21). The discrepancy could be a result of the extensive skeletal involvement of our cohort; in such a setting, BSI measurement might not perform adequately in detecting changes.…”

“…The automated BSI for the assessment of skeletal tumor burden in patients with prostate cancer is an example of such a diagnostic tool. The BSI has been proven to be valuable for prognostication, prediction, and response assessment in prostate cancer patients (11,(19)(20)(21).…”

Automated Bone Scan Index as an Imaging Biomarker to Predict Overall Survival in the Zometa European Study/SPCG11

“…However, the small sample size in this subgroup analysis is a clear limitation. Another limitation would be a variation in time between baseline and follow-up bone scan, when compared with the time used in previous aBSI studies [9][10][11][12][13]. Despite these limitations, this study shows that changes in aBSI are associated with survival even at earlier stages of the disease in high-risk PCa patients.…”

“…It has also been shown to be a potential tool for monitoring response in patients with metastatic castration-resistant prostate cancer (mCRPC) treated with docetaxel, new androgen signalling inhibitors, or tasquinimod [8][9][10][11][12]. Results from these studies have shown a strong correlation between aBSI and overall survival (OS), with a cut-off value of 1% of metastatic burden [4,13]. The importance of using baseline and follow-up values of aBSI to analyse the change in aBSI to predict the outcome has also been demonstrated in patients with advanced disease [4,13].…”

“…Results from these studies have shown a strong correlation between aBSI and overall survival (OS), with a cut-off value of 1% of metastatic burden [4,13]. The importance of using baseline and follow-up values of aBSI to analyse the change in aBSI to predict the outcome has also been demonstrated in patients with advanced disease [4,13].…”