From the Guidelines
The most effective blood tests to confirm prostate cancer, aside from PSA, are the Prostate Health Index (PHI) and the 4Kscore test, which can help improve diagnostic accuracy and determine the need for biopsy. These tests are designed to be used in conjunction with PSA testing to enhance specificity and reduce unnecessary biopsies. The PHI combines three forms of PSA to provide better specificity for cancer detection, while the 4Kscore test measures four prostate-specific kallikreins to assess cancer risk 1.
Some key points to consider when using these tests include:
- The PHI has been shown to potentially double the sensitivity of total or free PSA analysis for cancer detection in patients with serum PSA concentrations between 2 and 10 ng/dL 1.
- The 4Kscore test has been found to have value in informing biopsy decisions when PSA levels are elevated 1.
- The percent free PSA (%f PSA) test may also be considered in patients with PSA levels greater than 3 ng/mL who have not yet had a biopsy, as well as in men who have had at least one prior negative biopsy and are thought to be at higher risk 1.
- It is essential to note that no blood test alone can definitively confirm prostate cancer, and a definitive diagnosis requires a prostate biopsy, where tissue samples are examined under a microscope.
In terms of using these tests in clinical practice, the panel recommends consideration of %f PSA, 4Kscore test, and Prostate Health Index (phi) in patients with PSA levels greater than 3 ng/mL who have not yet had a biopsy 1. Results of any of these tests should be included in discussions between clinician and patient to assist in decisions regarding whether to proceed with biopsy.
From the Research
Blood Tests for Prostate Cancer Diagnosis
Other than PSA, several blood tests can help confirm the presence of prostate cancer. These include:
- PSA density: calculated as total PSA divided by prostate volume, it can help identify men at higher risk of clinically significant cancer 2
- PSA velocity: measures the change in PSA levels over time, and can be used to predict the risk of prostate cancer and high-grade cancer after an initially negative biopsy 3
- Free/total PSA ratio: measures the percentage of free PSA in the blood, and can help distinguish between prostate cancer and benign prostatic hyperplasia 4, 5
- PSA doubling time: measures the time it takes for PSA levels to double, and can be used to monitor disease progression and response to treatment 6
Diagnostic Parameters
Several diagnostic parameters can be used in combination with PSA to improve the accuracy of prostate cancer diagnosis. These include:
- PSA density of the transition zone: measures the density of PSA in the transition zone of the prostate, and can help predict the risk of prostate cancer 5
- Percent free PSA: measures the percentage of free PSA in the blood, and can help distinguish between prostate cancer and benign prostatic hyperplasia 5
- PSA velocity and doubling time: can be used to monitor disease progression and response to treatment, and to aid in clinical decision-making 3, 6
Clinical Applications
These blood tests and diagnostic parameters can be used in various clinical settings, including:
- Initial prostate cancer screening: to help identify men at higher risk of prostate cancer and to reduce unnecessary biopsies 2, 4
- Biopsy decision-making: to help determine which men should undergo biopsy and to reduce unnecessary biopsies 2, 3
- Disease monitoring: to monitor disease progression and response to treatment, and to aid in clinical decision-making 6