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Free PSA - Based Prostate Cancer Smart Screening Analysis
Considering Free PSA? Low Free PSA% ? | Before prostate cancer biopsy: analyze your PSA and Free PSA % trends, use new screening technology and consider smart screening strategy analysis.
PSA is the prostate-specific antigen blood test measured in ng/mL that reflects prostate conditions.
Learn more about your elevated or high PSA test level:
Free PSA is the component of PSA not bound to proteins ("free") measured in ng/mL.
Free PSA % is the ratio of Free PSA to PSA that is used with elevated or high PSA test levels to increase screening effectiveness.
Learn more about Prostate Smart Screening for Cancer at our home page in a new window
Take Next Steps to Develop Your Smart Screening Strategy
- Understand your "Underlying" "True" low Free PSA % and elevated or high PSA.
- Why does Free PSA % improve PSA screening effectiveness?
- Interpret your Free PSA %, elevated or high PSA and prostate volume.
- Analyze your elevated or high PSA trend and Free PSA % trend.
- Compare Free PSA to other enhanced tests - blood or urine.
- Develop Prostate Smart screening strategy for your Free PSA %.
1. Understand Your "Underlying" "True" Free PSA % and Elevated or High PSA
An elevated PSA (less than 5.0) or a high PSA (greater than 5.0) provide early warning of prostate activity for a smart prostate cancer screening strategy. (Links take you to one of our website pages that opens in a new window.)
A corresponding low Free PSA % provides additional early warning because low Free PSA % is associated with higher probabilities of prostate cancer found by biopsy.
Your "Underlying" "True" PSA and Free PSA % are the values that your physicians should use to assess your risk with the help of prostate cancer risk calculators or rules of thumb about threshold level of concern. Learn about risk calculators in the Blog post: Use prostate cancer risk calculators to avoid premature biopsy that opens in a new window.
Your "True" PSA is Hybritech calibrated and adjusted for specific medications to treat prostate enlargement (BPH). See the Blog post: Elevated PSA? Is your "True" PSA higher? that opens in a new window.
Your "True" Free PSA % should also be Hybritech calibrated for use with the PCPT Risk Calculator and popular look-up tables. Some past studies have shown that Free PSA % can vary by as much as 5%points for the same blood using tests from different suppliers. For example, Free PSA % for the same blood might be a low 12% from one supplier and a moderate 17% from another supplier. If you remain interested in Free PSA testing, it makes sense to consider the Prostate Health Index (PHI) test from Beckman Coulter because you don't have to worry about the calibration of Free PSA and PSA.
Your "Underlying" "True" PSA test level may be lower than your most recent "True" elevated PSA value because of temporary infection, inflammation or aggravation of your prostate. See the Blog post: Elevated PSA? Is your "Underlying" PSA lower? that opens in a new window.
Your "Underlying" "True" Free PSA % may be higher than your most recent "True" Free PSA % because Infections of the prostate and urinary tract tend to decrease Free PSA % when they increase PSA. If Free PSA % is low when PSA is elevated,
Follow-up testing is highly recommended for a long enough period for a possible infection to clear. See the Blog post: "Underlying" Free PSA, Prostate Health Index (PHI), 4Kscore, PCA3 in a new window.
2. Why Does Free PSA % Improve PSA Screening Effectiveness?
Free PSA % with PSA improves prostate cancer screening effectiveness compared to PSA alone:
- Both cancer and many non cancer prostate conditions increase PSA.
- Prostate cancer tends to decrease Free PSA % when it increases PSA.
- Many non-cancer prostate conditions tend not to decrease Free PSA % when they increase PSA, such as prostate enlargement. Free PSA % tends to "weed out" these conditions and increase screening effectiveness.
- Infections of the prostate and urinary tract tend to decrease Free PSA % when they increase PSA, which limits the effectiveness of Free PSA %. However, infections are often temporary with follow-up PSA decreasing and follow-up Free PSA % increasing to less alarming levels. Therefore, follow-up PSA and Free PSA tests are highly recommended.
3. Interpret Your Free PSA %, Elevated or High PSA and Prostate Volume
For any PSA level, the probability of prostate cancer:
- Increases as Free PSA % decreases.
- Increases as prostate volume decreases to small sizes.
What Is the Probability of High Grade or Significant Cancer for Free PSA % and PSA Levels?
The highly regarded PCPT Risk Calculator estimates the probability of high-grade (and low-grade) prostate cancer.
In this section, we focus on two of the most important factors, Free PSA % and PSA level, for men with no other risk factors. For an age 65 man who is not African American, the graph on the right plots the probability high grade prostate cancer will be found by biopsy as a function of Free PSA % for three PSA levels: 3.0, 6.0 and 9.0.
Notice that the probability of high-grade cancer increases steeply as Free PSA % decreases to 10% and below. The three curves show that the probability increases as PSA increases. These PCPT-RC results will vary as variable values change for: age, race, family history, DRE and prior biopsy.
What Is the Probability of High Grade or Significant Cancer for Free PSA % and Prostate Volumes?
The highly regarded ERSPC Risk Calculator estimates the probability of significant prostate cancer (high-grade and large low-grade) and the probability of any prostate cancer. We use the ERSPC-RC to adjust the 6.0 PSA curve above.
We focus on Free PSA % and prostate volume for men with no other risk factors. For PSA 6.0, the graph on the right plots the probability high grade prostate cancer will be found by biopsy as a function of Free PSA % for three prostate volumes estimated by digital rectal exam (DRE): small (25cc), medium (40cc) and large (60cc). The curves are dashed to indicate uncertainty in the two-step "what if" adjustment process.
Notice that the probabilities are much higher for a small prostate (the top red curve) than for a large prostate (the bottom blue curve). The probability of cancer is lower for large prostates because they tend to produce more PSA that "explains" elevated levels of PSA.
The dramatic difference in risk for small and large prostates demonstrates why it is so important to consider prostate volume for elevated PSA levels. The risk level of 10% is the same at 12% Free PSA % for a large prostate as at 21% Free PSA % for a small prostate. Full interpretation of Free PSA % depends on prostate volume. If you are considering using Free PSA, we suggest that you consider using the Prostate Health Index (PHI), which incorporates Free PSA and another blood test and is considered by the ERSPC Rick Calculator.
Ask your physician to estimate your prostate volume by digital rectal exam (DRE). Ask for a transrectal ultrasound (TRUS) to measure your prostate volume more accurately before considering a biopsy. To learn more see our Ultrasound-Based Prostate Cancer Smart Screening Analysis page in a new window.
4. Analyze Your Elevated or High PSA Trend and Free PSA % Trend
Analysis of your PSA trend and Free PSA % trend can provide valuable insights. See our Analyze Your Elevated or High PSA Trend and Free PSA % Trend page and our "Underlying" Free PSA, Prostate Health Index (PHI), 4Kscore, PCA3 Blog post in new windows.
For example, some men experience periodic infections of the prostate or urinary tract that cause their PSA to increase temporarily and their Free PSA % to decrease temporarily It would be a big mistake to use a temporarily increased PSA and decreased Free PSA % to assess underlying prostate cancer risk or estimate growth rate in PSA from cancer.
5. Compare Free PSA to Other Enhanced Tests - Blood or Urine
Enhanced blood tests used with prostate cancer risk calculators can substantially improve prostate cancer screening effectiveness compared to PSA alone. We describe and compare six combinations of enhanced blood and urine tests and risk calculators. See our Compare PSA, Free PSA, PHI, 4Kscore, PCA3 page in a new window for our full comparison.
Free PSA is one of several enhanced test alternatives for prostate cancer screening.
Prostate Health Index (PHI) and 4Kscore blood tests and PCA3 urine test are alternative enhanced tests that you can learn about in new windows.
Six Enhanced Test Combinations for Elevated and High PSA Test Levels (T1 to T6)
We consider six enhanced test combinations of blood and urine tests and risk calculators:
The two Free PSA enhanced test combinations (T1 and T2) are described below:
T1. Free PSA and PSA Blood Tests and Free PSA % Look-Up Table
T2. Free PSA and PSA Blood Tests and PCPT Risk Calculator
The highly regarded PCPT Risk Calculator considers both your Free PSA % and PSA along with your age, race, family history of prostate cancer, digital rectal exam (DRE) result and prior biopsy result. See Sections 4, 5 and 9 below.
Comparison of Enhanced Test Combinations for Elevated and High PSA Test Levels
We compare the six enhanced test combinations in five ways:
See our Compare PSA, Free PSA, PHI, 4Kscore, PCA3 page in a new window for our full comparison.
Cost and Reimbursement
Rough estimates of cost and reimbursement of the blood and urine tests:
Summary Comparison and Suggestions for Elevated or High PSA
There are three best enhanced test options with ranking based on what is important to you. Consideration of prostate volume (or not) is the biggest difference between PHI with ERSPC Risk Calculator using prostate volume and other alternatives.
If you are willing to operate the ERSPC Risk Calculator (and especially if either cost or consideration of prostate volume and TRUS ultrasound results are important to you) then consider:
If you are not willing to operate the ERSPC Risk Calculator and cost is not important to you then consider:
If you are not willing to operate the ERSPC Risk Calculator and cost is important to you then consider:
If you are concerned about operating the ERSPC Risk Calculator, we encourage you to enlist the help of a daughter, son, spouse or friend or even pay a student with computer skills.
Alternatively, we can operate the ERSPC Risk Calculator for you and create a full smart prostate cancer screening strategy report for you. Learn more about Prostate Smart Screening for Cancer at our home page in a new window.
6. Develop Your Prostate Smart Screening Strategy for Your Free PSA %
For men who want to lead a collaborative team effort rather than be a passive patient.
Prostate Smart analysis helps you create your strategy with your collaborative team of physicians and confidants to minimize your risks of:
> Regrettably late diagnosis of deadly cancer:
> Premature biopsy, diagnosis, treatment and side effects:
Analysis is needed to create the best personal screening strategy for you because:
We analyze published studies and present the implications for personal decisions. Studies are from: Mayo Clinic, Cleveland Clinic, Johns Hopkins, Memorial Sloan Kettering, NIH, NYU, UCLA, UC London, Yale and more.
Learn more about PSA-Based Prostate Smart Screening Strategy Analysis in a new window.
Return to Prostate Smart Screening for Cancer home page.