aBSI becomes an attractive alternative for prostate cancer prognosis

Prostate cancer commonly metastasizes to bone, and bone metastases are associated with pathologic fractures, pain, and reduced survival. Behind a major study of 721 participants in a randomized clinical trial, it has been discovered that the automated Bone Scan Index is significantly associated with the overall survival (OS) in men with metastatic castrate-resistant prostate cancer (mCRPC).

Between March 2011 and August 2015, men with bone metastatic chemotherapy-naïve CRPC were recruited from 37 countries. The analysis of aBSI was conducted between May 25, 2016, and June 3, 2017.

Why aBSI – automated Bone Scan Index?

Other than skin cancer, prostate cancer is the most common cancer in American men. The American Cancer Society’s estimates for prostate cancer in the United States for 2018 are:

• About 164,690 new cases of prostate cancer
• About 29,430 deaths from prostate cancer

Among patients who die from PCa, the incidence of skeletal involvement appears to be >85%. Bone scan (BS) is the most common method for monitoring bone metastases in patients with PCa. The BSI represents tumor burden as a percentage of total skeletal weight. The system used in this study automates BSI methods by using artificial neural networks to detect metastatic hot spots and classify them as malignant or benign.

The aim of this analysis published in JAMA Oncology was to investigate automated BSI (aBSI) measurements as predictors’ survival in PCa.

Of the total 1245 men enrolled, 721 were evaluable for the aBSI.

aBSI measurements – What do they predict about prostate cancer progression?

Patients were divided into four aBSI quartiles, as follows:

• Quartile 1 — median aBSI, 0.05; median OS, 34.7 months
• Quartile 2 — median aBSI, 0.58; median OS, 27.3 months
• Quartile 3 — median aBSI, 2.06; median OS, 21.7 months
• Quartile 4 — median aBSI, 6.72; median OS, 13.3 months

The authors of the study, led by Andrew Armstrong, MD, Duke University, Durham, North Carolina say that the risk of all-cause mortality increased by 20% with each doubling of the aBSI. “The patients in subgroups with a mean baseline aBSI of 0.2 or lower had a median OS longer than 30 months,” researchers add, “while the patients in subgroups with a median baseline aBSI of 5.6 or higher had a median OS shorter than 15 months.”

Also, they added that the aBSI was weakly associated with pain scores, based on the fact that some men with a high burden of bone metastases report little to no pain, whereas others with a lesser burden of skeletal disease report significant pain.

On December 2017, in the World Journal of Nuclear Medicine has been published another study that had the same objective, aBSI measurements were shown to be a strong prognostic survival indicator in PCa; survival was poor in high-BSI value. A total of 35 subjects deaths were registered, with a median survival time 36 months after the follow-up BS of 5 years. Subjects with low aBSI value had longer overall survival in comparison with the other subjects (P = 0.004).

Until now, there was no clinically useful technique for measuring bone tumors and includes this information in the risk assessment. Thanks to Automated BSI, BSI is developing into a widespread tool for nuclear medicine physicians, urologists, and oncologists.

The utility of the aBSI system in prostate cancer prognosis

“With ongoing and future work in validating aBSI, this technology could eventually be introduced in clinical practice and research settings for improved stratification,” comments Fred Saad, MD, University of Montreal Hospital Center, Quebec, Canada, in an accompanying editorial.

The study prospectively validates the potential utility of an automated BSI (aBSI) system to evaluate the burden of bone metastases seen on bone scan and establish its prognostic value. “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,” the investigators conclude.

The term metastatic castration-resistant prostate cancer (mCRPC) refers to cancer that has spread (metastasized) beyond your prostate gland and for which hormone therapy is no longer effective in stopping or slowing the disease.

For more details about prostate cancer, please feel free to contact Dr. David Samadi. He will be happy to guide you regarding your issue. Think positive! A little progress each day adds up to big results!