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Automated bone scan index as an imaging biomarker in metastatic castration resistant prostate cancer (mCRPC) patients treated with radium-223.
Background: There are no validated imaging tools to assess response to the Radium-223 (Ra 223). In this study, we explored the analytically validated automated bone scan index (auto-BSI) as an imaging biomarker in mCRPC Patients (Pts) treated with Ra-223. Methods: In a multi-center retrospective study, available bone scans of mCRPC Pts treated with Ra 223, were collected at baseline (BL) and at treatment follow-up (Tx-FU). The auto-BSI was analyzed using the EXINIboneBSI version 2. Logistic regression, cox regression and Kaplan Meier analyses evaluated the auto-BSI associations with PSA response, defined as 50% decline from BL; pain response, defined as decrease in the VAS score from BL; Alkaline phosphatase (ALP) response, defined as 30% decline from BL; and with overall survival (OS). Results: Of144 Pts treated with Ra223, 66 (46%) had a BL bone scan and 25 of them also had a Tx-FU bone scan taken 18 to 30 weeks after the first treatment. No significant differences were observed in BL characteristics of Pts with bone scans versus without. The median number of ra223 doses were 6 (1-6). Median BL auto-BSI was 2.4 (range:0.01–33.2) and median Tx-FU auto-BSI was 0.5 (range:0-20.1). The BL auto-BSI was associated with OS (HR = 1.4; 95%CI = 1.1-2.0) and with ALP response (HR = 1.6; 95%CI = 1.04-2.4), p = 0.02. BL auto-BSI was not associated with pain, p = 0.48, or with PSA response, p = 0.76. OS at 9 months with BL auto-BSI < 5 was 76% vs. 40% in Pts with BSI > 5. In Tx-FU analysis, 17 (68%) of the 25 Pts had ≥ 30% decrease in auto-BSI from BL; Only 5 (20%) Pts were PSA responders, and all 5 Pts had ≥ 30% decrease in auto-BSI. Conclusions: Baseline auto-BSI was associated with OS and with ALP response. The findings encourage prospective investigations to validate the role of BSI as an imaging biomarker in mCRPC Pts being treated with Ra-223.
Abstracts by Aseem Anand:
Translating Prostate Cancer Working Group 2 (PCWG2) progression criteria into a quantitative response biomarker in metastatic castration-resistant prostate cancer (mCRPC).Meeting: 2017 Genitourinary Cancers Symposium | Abstract No: 170
Automated bone scan index as a quantitative imaging biomarker indicative of efficacy to enzalutamide in patients with metastatic castrate resistant prostate cancer (mCRPC).Meeting: 2016 Genitourinary Cancers Symposium | Abstract No: 226