Prostate cancer test developed in record time thanks to biobank access
Stockholm3 is a new blood-based test to predict the risk for aggressive prostate cancer. Compared to conventional prostate cancer testing with PSA tests, the Stockholm3 test reduces the number of unnecessary biopsies by 50% and can also find aggressive cancer in men with low PSA values. It would have been impossible to develop the Stockholm3 test without access to large patient registers and biobanks, comments project leader Martin Steinberg.
The Stockholm3 test was developed in record time and was available for clinical use in Sweden already in 2016 – only four years after project start.
Patient registers helped mapping out the diagnostic situation
The development team started with analyzing data from 500,000 men tested for prostate cancer in Stockholm since 2003, using the Stockholm PSA and Biopsy Register, a database with complete records of PSA tests, biopsy/pathology results and detailed cancer information.
“It’s quite unique to have access to a register with complete data. This made it possible for us to better map out the diagnostic situation and create a structure for developing the test”, comments Steinberg.
Retrospective studies with biobank material to identify markers
First, a literature search was conducted to identify promising plasma biomarkers, genetic markers, and clinical markers. A retrospective study was then conducted, using a cohort of 400 biopsied cases from KI Biobank at Karolinska Institutet in Stockholm, Sweden, which identified 11 plasma biomarkers, 256 genetic markers, and 6 clinical markers as promising. The markers were validated in a larger retrospective study with 1,200 biopsied cases, which trimmed down the number of plasma biomarkers from 11 to 6.
“If we hadn’t had access to all the biobanked material, this part of the development process would’ve taken several years. We could do it in a few months. In fact, the Stockholm3 test wouldn’t have been developed at all without access to the biobank”, says Steinberg.
Developing the algorithm
The next step was to develop an algorithm for the Stockholm 3 test. A prospective study with more than 11,000 participants was conducted to define the algorithm, and a second, even larger prospective study with more than 47,000 participants was conducted to verify the algorithm. The algorithm was then fine-tuned, whereby the final number of markers could be reduced to 5 plasma biomarkers, about 100 genetic markers, and 5 clinical markers.
A key to succeed with these types of development projects is to have access to biobanks with the right type of samples and a high sample integrity.
“KI Biobank is a service provider with no academic agenda, and they are very agile and dedicated. The competitive edge is that you can make fast withdrawals. You don’t have to wait for months; it only takes a few days. We made 48 withdrawals from 2014 to 2017 and in total we’ve taken out more than 42,000 cherry-picked aliquotes so it’s incredibly important to have fast withdrawals. A high level of automatization and a high level of IT integration are other core capabilities of KI Biobank excellency”, says Steinberg.
The Stockholm3 test is in clinical use in Sweden, Norway, Denmark, and Finland, and is currently being launched on a large scale in Europe. The development of Stockholm3 has also led to a new resource – biopsies from 7,417 men that were taken as part of the prospective studies. This material is currently being used to develop a new AI-supported tool, OncoWatch Image, to reduce variability in pathology assessment.