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What Is Prostate Specific Antigen

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Psma In Prostate Cancer

What is Prostate Specific Antigen (PSA) Testing – Urology Specialists of the Carolinas

PSMA is a type II membrane protein composed of a 707-amino acid extracellular domain, a 24-amino acid transmembrane domain, and a 19-amino acid intracellular domain. Studies utilizing PSMA in serum as a biomarker of prostate cancer had mixed results; however, tissue expression of PSMA correlates with prostate cancer aggressiveness. Initial imaging of PSMA started with a labeled antibody, capromab pendetide; however, similar to most radiolabeled antibodies, uptake was characterized by slow blood clearance and poor tumor penetration. New lower molecular weight probes include N-carbamoyl]-4-fluorobenzyl-l-cysteine , a urea-based second-generation inhibitor of PSMA developed by the Pomper lab following earlier work with MIP-1072 and MIP-1095 for single photon imaging. A recent first in patient study of DCFBC in patients with metastatic prostate cancer showed similar radiation dosimetry as FDG and prolonged blood activity. Further studies are warranted to compare this compound to other prostate imaging probes discussed earlier. Other PSMA tracers have been developed notably one from the Haberkorn lab, Glu-NH-CO-NH-Lys–. The lesion detection rate of this new tracer in the diagnosis of recurrent prostate cancer was reported as 79.1% and the tracer was found to be superior to FMCh .

Mohsen Beheshti, … Werner Langsteger, in, 2018

What Are Some Of The Limitations And Potential Harms Of The Psa Test For Prostate Cancer Screening

Detecting prostate cancer early may not reduce the chance of dying from prostate cancer. When used in screening, the PSA test can help detect small tumors that do not cause symptoms. Finding a small tumor, however, may not necessarily reduce a mans chance of dying from prostate cancer. Many tumors found through PSA testing grow so slowly that they are unlikely to threaten a mans life. Detecting tumors that are not life-threatening;

that requires treatment.

Limitations Of The Psa

For a test to be useful, doctors should be able to tell you whether your result is normal. Most tests have a well-established range of normal values, but for the PSA, even this apparently simple issue is controversial. Most doctors in the United States use 4.0 nanograms per milliliter as a cutoff, considering results below that as normal and higher values as abnormal. But since PSA values tend to rise with age, even in healthy men, other authorities have proposed a range of normal values adjusted for age .

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What If A Screening Test Shows An Elevated Psa Level

If a man who has no symptoms of prostate cancer chooses to undergo prostate cancer screening and is found to have an elevated PSA level, the doctor may recommend another PSA test to confirm the original finding. If the PSA level is still high, the doctor may recommend that the man continue with PSA tests and DREs at regular intervals to watch for any changes over time.

If a mans PSA level continues to rise or if a suspicious lump is detected during a DRE, the doctor may recommend additional tests to determine the nature of the problem. A urine test may be recommended to check for a urinary tract infection. The doctor may also recommend imaging tests, such as a transrectal ultrasound, x-rays, or cystoscopy.

If prostate cancer is suspected, the doctor will recommend a prostate biopsy. During this procedure, multiple samples of prostate tissue are collected by inserting hollow needles into the prostate and then withdrawing them. Most often, the needles are inserted through the wall of the rectum . A pathologist then examines the collected tissue under a microscope. The doctor may use ultrasound to view the prostate during the biopsy, but ultrasound cannot be used alone to diagnose prostate cancer.

How To Get A Psa Test


Consult with your general practitioner or urologist about receiving a PSA test in their offices. PSA tests are typically covered without co-pay or deductible by Medicare once a year for men 50 years and older. Many states now have laws which require private health insurers to cover the costs for PSA testing. However, additional PSA test costs may need to be covered by the patient. For those without insurance, or for those with insurance that does not cover PSA testing, free tools are available through advocacy groups, such as ZERO.

Companies such as;imawaretm;also offer in-home PSA testing kits and telemedicine appointments to discuss your PSA test results with a licensed physician. All imaware test kits are easy to use. After registering the test kit online, results will populate in the secure patient portal within 5-7 business days. You can submit your receipt of this test to insurance for potential reimbursement.

“At-Home testing is now at a point where results can be provided accurately and quickly within 5 business days, with real physicians providing telemedicine support through the entire testing process”

Dr. Diamandis – Lunenfeld-Tanenbaum Research Institute, Sinai Health System


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Screening Tests For Prostate Cancer

Screening is testing to find cancer in people before they have symptoms. Its not clear, however, if the benefits of prostate cancer screening outweigh the risks for most men. Still, after discussing the pros and cons of screening with their doctors, some men might reasonably choose to be screened.

The screening tests discussed here are used to look for possible signs of prostate cancer. But these tests cant tell for sure if you have cancer. If the result of one of these tests is abnormal, you will probably need a prostate biopsy to know for sure if you have cancer.

What Is Digital Rectal Examination

Most prostate cancers are located in the peripheral zone of the prostate and may be detected by DRE. During this examination a doctor inserts a finger into the rectum to feel the prostate for lumps, size, shape, tenderness, and hardness. A suspect DRE is an absolute indication for prostate biopsy, regardless of the PSA level. In about 18% of patients with abnormal DRE, prostate cancer will be detected regardless of the PSA level.

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When Should You Test Your Levels

Up until recently, professional organizations recommended yearly PSA screening for all men once they turn 40. Some advocated even earlier screening for high-risk populations, such as African Americans or men who have a family history of prostate cancer .

However, recent findings turned the guidelines around. Studies revealed that some men with normal PSA levels have prostate cancer, while many men with higher levels do not .

New reports indicate that the widespread use of PSA tests led to prostate cancer overdiagnosis in the United States. In turn, many professional associations revised their guidelines, turning against routine screening in most cases and especially in men under 55 or over 70 years old .

The overall benefit of PSA screening for prostate cancer in men aged 55 to 69 years is small. Ultimately, men in this age group have to decide whether they want to have the PSA test done or not, even if they belong to a high-risk group .

To decide whether to have a PSA test, discuss the issue with your doctor, considering your risk factors and weighing your personal preferences. We will now discuss some of the limitations of this test.

The Case For Psa Screening

The Prostate Specific Antigen (PSA) Test

The American Cancer Society recommends that doctors discuss annual PSA testing with every man above the age of 50 who has a life expectancy of 10 years or longer; it also calls for yearly discussions to start at the age of 45 for men at increased risk, including African Americans and men with family histories of prostate cancer. The ACS says that if a man cannot decide, his doctor should recommend testing. The American Urological Association also recommends PSA screening. Until 2009, they had the same guidelines as the ACS, but their guidelines now call for doctors to offer the test to all men with a life expectancy of at least 10 years, beginning at age 40.

They have a point. Requiring only a single blood sample, PSA testing is quick, easy, and safe. With a typical cost of about $40, it is inexpensive, and technical improvements have made it reliable in most labs.

Advocates of PSA screening point out that the test has the potential to detect about 80% of prostate cancers. Without screening, some 40% of prostate cancers are not diagnosed until they have spread too far to be curable. Early detection is surely the best hope for curing prostate cancer, and PSA screening is the best way to find early disease.

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How To Get Tested

Samples used for PSA testing are collected by trained health care professionals at hospitals, labs, and other medical settings. Before getting tested, its best to talk to your doctor about the risks and benefits of PSA testing. You may be able to schedule your own PSA test at a clinic or laboratory without a doctors order. However, you will need a doctor to interpret the results of your test and recommend next steps.

Maximum Values Of Psa That Are Considered Normal

The tables have varied considerably as new factors that raise or reduce the PSA arediscovered. As mentioned above, it is also common to discover cancer in men whosePSA is below 2.0 ng/ml. Nor is it rare to find patients with no evidence of cancer of theprostate but with PSA levels that are above 70 ng/ml. In general, if the level is above 4ng/ml there is a greater possibility of finding one or more following diseases such as theones listed below:

  • Any surgery in the groin area such as hernia surgery, vasectomy, etc.
  • Mammary carcinoma
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    Help To Continue The Work

    The Prostate Cancer Free Foundation, reviews the results of hundreds of thousands of men treated for prostate cancer. Tracking them for years. This information is available to you, and others like you, to help find the best prostate cancer treatment. This work takes time, effort, resources all of it done by volunteers. Please help us continue. Please Donate!

    Psa In Other Biologic Fluids And Tissues

    Overview of the Prostate

    Concentration of PSA in human body fluids

    female serum 0.01 – 0.53

    It is now clear that the term prostate-specific antigen is a misnomer: it is an antigen but is not specific to the prostate. Although present in large amounts in prostatic tissue and semen, it has been detected in other body fluids and tissues.

    In women, PSA is found in female ejaculate at concentrations roughly equal to that found in male semen. Other than semen and female ejaculate, the greatest concentrations of PSA in biological fluids are detected in breast milk and amniotic fluid. Low concentrations of PSA have been identified in the urethral glands, endometrium, normal breast tissue and salivary gland tissue. PSA also is found in the serum of women with breast, lung, or uterine cancer and in some patients with renal cancer.

    Tissue samples can be stained for the presence of PSA in order to determine the origin of malignant cells that have metastasized.

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    Psa Testing For Detection Of Prostate Cancer

    The introduction of prostate-specific antigen testing into clinical practice has greatly increased the detection of localized prostate cancer and, by doing so, has decreased the diagnosis of regional and metastatic disease. PSA testing has had such a profound clinical effect that questions have arisen regarding the significance of the cancers that are being detected.

    Stage, grade, tumor volume, and PSA testing are used to determine whether a prostate cancer is clinically significant or insignificant. However, there is no generally accepted precise definition for this distinction.

    The goal of early detection of prostate cancer is to identify clinically significant cancers at a time when treatment is most likely to be effective. The risk of death from prostate cancer is significant in those with moderate- to high-grade tumors. This is especially true in younger men. Long-term survival is compromised when the cancer has spread beyond the confines of the prostate, into the regional lymph nodes, and to distant sites.

    Several studies have shown that with a PSA cutoff of 4.0 ng/mL, clinically insignificant cancers are detected in fewer than 20% of men, but nearly 50% of all the cancers detected because of an elevated PSA level are localized, and these patients are candidates for potentially curative therapy. Only a small proportion of prostate cancers detected by PSA testing and treated with radical prostatectomy are low-volume and low-grade tumors.

    What Does A High Psa Level Mean

    High PSA levels could be a sign of prostate cancer or a different condition like prostatitis or an enlarged prostate.

    Other things can affect your PSA level:

    • Age. Your PSA will normally go up slowly as you get older, even if you have no prostate problems.
    • Medications. Some drugs may affect blood PSA levels. Tell your doctor if youâre taking dutasteride or finasteride . These drugs may falsely lower PSA levels by half of what they should be.

    If your PSA level is high, your doctor may suggest that you get a prostate biopsy to test for cancer.

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    Can I Take The Test At Home

    Although testing for PSA at home is uncommon, several at-home PSA tests are available. At-home PSA tests typically involve collecting samples of blood at home through a fingerstick and sending the samples into a laboratory for testing. When considering at-home PSA testing, its important to understand the potential harms of this test.

    At-home testing may be less accurate than testing a sample taken from a vein. PSA testing can also show a higher result when cancer isnt present and can lead to additional diagnostic procedures. Because the role of PSA testing is highly individualized, its important to seek testing only under the care and guidance of a doctor.

    Pros And Cons Of The Psa Test

    Prostate Cancer Screening: What is Prostate-Specific Antigen (PSA)?


    • it may reassure you if the test result is normal
    • it can find early signs of cancer, meaning you can get treated early
    • PSA testing may reduce your risk of dying if you do have cancer


    • it can miss cancer and provide false reassurance
    • it may lead to unnecessary worry and medical tests when there’s no cancer
    • it cannot tell the difference between slow-growing and fast-growing cancers
    • it may make you worry by finding a slow-growing cancer that may never cause any problems

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    Variations On A Theme

    Even before the PLCO and ERSPC results were unveiled in the spring of 2009, researchers were aware of limitations of PSA screening. Several modifications have been proposed, but none has proved superior to the PSA itself. One approach relies on measurements of both the total PSA and the free PSA. Cancer is more likely when the free PSA constitutes less than 25% of the total PSA; the lower the percentage of free PSA, the more likely the diagnosis of cancer. Another refinement depends on serial measurements of the PSA, typically at yearly intervals. The PSA velocity reflects the rate of change; researchers suggest that a rise of more than 0.75 ng/mL over the course of a year increases the likelihood of cancer. A similar modification, the PSA doubling time, helps doctors establish the prognosis for patients with prostate cancer; the shorter the doubling time, the worse the outlook.

    Normal Psa Levels By Age Chart

    We mentioned earlier in this article that PSA levels increase with age due to age related growth of the prostate gland. A doctor will therefore take into account an age-adjusted PSA level when discussing your prostate health:

    Age Range

    0 to 6.5

    Although there are normal PSA levels by age range, it is still important to screen routinely to ensure these normal levels are not rising.

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    What Is The Cost Of The Psa Test

    The PSA blood test is frequently covered by insurance, especially for men who are 50 years of age and older. PSA blood tests costs $20-$50. However, if it is obtained in the doctor’s office during a visit to the doctor there may be an additional charge of $25-$100 for the office visit. There are PSA blood tests available for home use. The home blood test comes with a lancet to prick your finger and squeeze out a sample of blood, a kit to collect the blood, a bandage, and an address or prepaid mailer to return to the laboratory. Not all of the advertised home blood tests are approved by the U.S. Food and Drug Administration . You can access the FDA web site to make sure you are using an approved test.

    What Does Psa Mean

    ProStvaC mechanism of action. PSA: Prostate

    PSA, or prostate-specific antigen, is a protein produced by the prostate and found mostly in semen, with very small amounts released into the bloodstream. When theres a problem with the prostatesuch as the development and growth of prostate cancermore PSA is released. Sometimes, a mans prostate releases slightly high PSA for other reasons. Rising PSA eventually reaches a level where it can be easily detected by a blood test.

    For more information on rising PSA, download or order your free copy of the Prostate Cancer Patient Guide.

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    Screening For Early Disease

    The purpose of any screening test is to detect disease before it becomes clinically evident. Routine measurements of blood pressure and cholesterol are examples of screening tests that have proved their worth. In the realm of cancer screening, Pap tests for cancer of the cervix, mammograms for breast cancer, and various tests for colon cancer have gained widespread acceptance.

    A screening test is successful if it meets several goals:

  • It has a high sensitivity; that is, it detects a high percentage of cases while missing few

  • It has a high specificity; that is, it doesn’t falsely diagnose disease when none is present

  • The test is reliable and reproducible and also safe, convenient, and inexpensive enough to gain widespread acceptance

  • Above all, the test must lead to a treatment that will improve the patient’s quality of life, extend the duration of his life, or both. In a word, the test should do more good than harm.

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