medwireNews: Prospective data confirm use of the automated Bone Scan Index (aBSI) as an independent prognostic marker of survival and other clinical outcomes in men with metastatic castration-resistant prostate cancer (mCRPC), researchers report.
Andrew Armstrong (Duke University, Durham, North Carolina, USA) and colleagues say their findings “support the clinical utility of the aBSI given its association with clinically relevant outcomes that are critically important in patient care.”
The study included 721 men (mean age 70.6 years) with chemotherapy-naïve bone-metastatic CRPC who were participating in a phase III placebo-controlled clinical trial of tasquinimod (the 10TASQ10 study). It showed that the risk for death increased by a significant 20% with each doubling of aBSI.
Median overall survival (OS) was 34.7 months among men in the lowest aBSI quartile (median aBSI=0.05), 27.3 months for those in the second quartile (median aBSI=0.58), and 21.7 and 13.3 months for men in quartiles 3 (median aBSI=2.06) and 4 (median aBSI=6.72), respectively.
This corresponded to 65%, 56%, and 40% lower risks for death among men in quartiles 1, 2, and 3, respectively, compared with men in quartile 4.
Armstrong and team found that aBSI, which represents the total tumor burden as the fraction of total skeleton weight, had a significantly greater discriminative ability in predicting OS than that of manual lesion counting.
Furthermore, multivariate analysis showed that aBSI remained independently associated with OS after adjustment for other significant prognostic markers such as serum prostate-specific antigen and C-reactive protein.
The researchers report in JAMA Oncology that a higher aBSI was also significantly and independently associated with time to symptomatic progression and time to opiate use for cancer pain.
And it correlated strongly with the number of bone lesions at study entry as well as serum levels of alkaline phosphatase (ALP) and bone-specific ALP at baseline.
Armstrong et al conclude: “Incorporating the aBSI into clinical practice to supplement nuclear medicine reports may permit a more objective analysis of bone scan changes over time and their clinical relevance to patient care.”
They add: “Subsequent analyses are ongoing to define and validate the aBSI increase as a progression end point biomarker for determining response and benefit to systemic therapies in men with bone mCRPC.”
In an accompanying commentary, Fred Saad, from the University of Montreal Hospital Center in Quebec, Canada, said that although the aBSI system has some limitations, particularly in the setting of very high tumor burden, it is “an encouraging framework on which to build.”
He concludes: “With ongoing and future work in validating aBSI this technology could eventually be introduced in clinical practice and research settings for improved stratification.”
By Laura Cowen
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