Arguably, there are few things men look less forward to than the thought of prostate examination. The reasons for their trepidation range from the comical to somber reality of facing the second most common form of cancer among men worldwide—prostate cancer—with over 1.2 million cases diagnosed in 2012 alone. The uneasiness that many men feel about the screening process, however, is not wholly unjustified, as the main diagnostic used to determine if a patient has prostate cancer, the prostate-specific antigen (PSA) test, has long been controversial due to its high false hit rate.
However now, a new study led by scientists at the Karolinska Institutet, in collaboration with Thermo Fisher Scientific, shows that a new test for prostate cancer is better at detecting aggressive cancer than PSA. This new screening method has undergone a clinical trial in 58,818 men and was able to detect aggressive cancer earlier, reduce the number of false positives, and decrease the number of unnecessary biopsies.
“PSA can’t distinguish between aggressive and benign cancers,” explained lead author Henrik Grönberg, M.D. Ph.D., professor of cancer epidemiology at the Karolinska Institute. “Today, men who don’t have cancer or who have a form of cancer that doesn’t need treating must go through an unnecessary, painful, and sometimes dangerous course of treatment. On top of this, PSA misses many aggressive cancers. We, therefore, decided to develop a more precise test that could potentially replace PSA.”
To date, no diagnostic test based upon the STHLM3 model has yet been approved for use by the U.S. Federal Drug Administration or other regulatory agencies outside the U.S.
The new procedure, called the STHLM3 test analyzes a simple blood sample from the patient for a combination of six protein markers (PSA, free PSA, intact PSA, hK2, MSMB, and MIC1) and 232 single nucleotide polymorphisms (SNPs), along with clinical data such as age, family history and previous prostate biopsies.
The findings from the study were published today in The Lancet Oncology through an article entitled “Prostate cancer screening in men aged 50–69 years (STHLM3): a prospective population-based diagnostic study.”
The STHLM3 test and PSA were performed on all participants and then compared side-by-side. The results showed that the STHLM3 test reduced the number of biopsies by 30% without compromising patient safety. In addition, the STHLM3 test found aggressive cancers in men with low PSA values (1-3 ng/mL)—which typically go undetected by current methodologies.
“This is indeed promising results. If we can introduce a more accurate way of testing for prostate cancer, we'll spare patients unnecessary suffering and save resources for society”, noted Dr. Grönberg. “The STHLM3 tests will be available in Sweden in March 2016, and we will now start validating it in other countries and ethnic groups.”
Joseph Bernardo, president of Thermo Fisher’s clinical next-generation sequencing and oncology business, added that “the study authors put this all in perspective by pointing out that a 30% reduction in prostate biopsies would translate to 300,000 fewer procedures annually in the U.S. So, in addition to improving patient experience and outcomes, there is also the potential for significant healthcare cost savings.”