The Role of the Total to Free PSA Ratio in Prostate Cancer Screening
In 2023, nearly all initial prostate cancer screening are a prostate specific antigen test, even though we know free PSA levels double the prognostic abilities of prostate cancer screening for patients in diagnostic grey zone.
In the United States, 85% of physicians decisions on patient health are based off diagnostic testing. Total PSA and Total/Free PSA have been shown in multi-center clinical trials to enhance cancer probabilities by more than 50%¹ for patients in the diagnostic grey zone, as well as reducing the total number of biopsies for all patients.²
In addition to being the most convenient blood sampling method available, Prostate IQ™ was designed to give physicians the most complete picture of overall prostate health at the beginning of the screening process.
"Use of the percentage of free PSA can reduce unnecessary biopsies in patients undergoing evaluation for prostate cancer, with a minimal loss in sensitivity in detecting cancer. A cutoff of 25% or less free PSA is recommended for patients with PSA values between 4.0 and 10.0 ng/mL and a palpably benign gland, regardless of patient age or prostate size. To our knowledge, this study is the largest series to date evaluating the percentage of free PSA in a population representative of patients in whom the test would be used in clinical practice"³
By beginning the screening process, patients create a baseline PSA level at their first PSA screening (important for high-risk populations such as persons with a first degree family relative with prostate or breast cancer) to guage PSA velocity over time. Based on a patients age and ethnicity, these data points provide important information on overall prostate health. However, PSA velocity is only available after subsequent testing, therefore most initial PSA tests only quantify total psa levels. Since PSA is an individual number and is not specific to prostate cancer, physicians have limited data with known specificity issues and are reluctant to act in the diagnostic grey zone (4ng/mL to 10ng/mL). Adding the total PSA/ free PSA ratio has been proven⁴ in multi-center clinical trials to prognostically identify 31% more prostate cancers while discouraging additional testing in patients with benign prostatic hyperplasia (BPH), a condition that causes PSA levels to rise naturally that is not life threatening.
For these reasons, Prostate IQ™ delivers the most useful analytes in the fight against prostate cancer to both patient and physician. Download the full article here.
¹ ² ³ ⁴ Catalona, et. al