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New prostate cancer screening model could reduce unnecessary biopsies
Last Updated: 2015-11-11
By Will Boggs MD
NEW YORK (Reuters Health) - A new prostate cancer screening model could reduce the number of unnecessary biopsies without compromising the diagnosis of clinically important prostate cancer, according to results from the Stockholm 3 (STHLM3) study.
"The STHLM3 test is a simple blood test that can reduce the risks connected with (prostate-specific antigen) PSA testing such as over-diagnosis and overtreatment and at the same time identify aggressive prostate cancers earlier," Dr. Henrik Gronberg from Karolinska Institute, Stockholm, Sweden, told Reuters Health by email.
"In Sweden, the Board of Health and Welfare, which is responsible for national screening guidelines, has therefore decided to reevaluate the current recommendations on prostate cancer screening for a potential national screening program of asymptomatic men," he said.
The STHLM3 model combines PSA, single nucleotide polymorphisms (SNPs), clinical variables, and established and novel plasma protein biomarkers.
Dr. Gronberg's team investigated the diagnostic value of their STHLM3 model in a prospective, population-based study of nearly 50,000 men without prostate cancer aged 50 to 69 years.
All variables used in the STHLM3 model were significantly associated with high-risk prostate cancers, and STHLM3 performed significantly better (AUC, 0.74) than PSA alone (AUC, 0.56) for detection of high-risk prostate cancers.
Using the same sensitivities to detect high-risk prostate cancers for STHLM3 and PSA alone, the STHLM3 model would reduce the number of biopsies by 32% and the number of benign biopsies by 44%.
"To put these numbers in perspective," the researchers note, "a 30% reduction in prostate biopsies translates to 300,000 fewer procedures annually in the USA."
The STHLM3 model identified 722 cancers with a Gleason score of 6, compared with 867 identified with PSA alone, a 17% reduction. All such cancers not identified by the STHLM3 model had a total cancer length of less than 10 mm in the biopsy samples.
The STHLM3 performed equally well in all age groups, and it remained superior to PSA alone even when digital rectal exam and prostate volume were excluded from the model, according to the November 9 Lancet Oncology online report.
"The STHLM3 test may detect aggressive cancers earlier, helping to reduce the number of false positive tests that can lead to unnecessary invasive biopsies," Dr. Gronberg said.
"We are still in the translational research stage at this point and pricing is not yet available," he said. "However, we have done an extensive health economic evaluation within the Swedish health care system, which shows that the test will save money for the Swedish health care provider even if the test was priced up to 500 USD."
"In Sweden the STHLM3 test will be available as a laboratory developed test in March 2016," Dr. Gronberg said. "Together with Kaiser Permanente in Northern California we will evaluate the STHLM3 test in a multiethnic American population in 2016. We have been contacted by groups/organizations in several other countries who are interested in validating the test in their respected geography/clinical setting."
Dr. Marianne Schmid from University Hospital Hamburg-Eppendorf, Hamburg, Germany, who has reported on the use of biomarkers for prostate cancer (http://bit.ly/1Y4NH2y), told Reuters Health by email, "On the one hand, screening for prostate cancer mainly guided by PSA-level measurement leads to over-diagnosis and over-treatment; on the other hand, there are still men who are screened but will die from prostate cancer. So the big issue is to detect aggressive and high risk cancers."
"In my opinion it is already obvious that not a single biomarker will help solve this issue, but a combination of biomarkers and clinical aspects," Dr. Schmid said. "However, seen from an economic point of view, research should also focus on cost-effectiveness of screening methods; new screening tools need to prove their efficacy also in terms of practicability and easy access."
"This approach seems feasible," Dr. Schmid concluded. "However, the process seems to be quite extensive (several clinic parameters and biomarkers are included in a model, genotyping, etc.) and probably expensive; as the authors conclude themselves: the model can be used as an 'aid' to identify high-risk prostate cancer. However, this needs to be validated in other countries first."
The Stockholm County Council primarily funded this research. Two coauthors reported relevant relationships.
Lancet Oncol 2015.