PSA

What is Prostate Specific Antigen (PSA)?

PSA is produced exclusively by cells of the prostate gland. Used in conjunction with the digital rectal examination, PSA is a useful screening test for benign prostate enlargement, prostatitis and prostate cancer development.

There are some things a man should not do before having a PSA test. This list of “don’ts” will help ensure your test results are as accurate as possible.

Prior to a PSA Test: Don’t Do These Activities

• Participate in vigorous exercise and activities that stimulate or “jostle” the prostate, such as bike riding, motorcycling, and riding a horse, ATV, or tractor, or getting a prostatic massage for 48 hours before your test.
• Participate in sexual activity that involves ejaculation for 48 hours before your test. Ejaculation within this time frame may affect PSA results, especially in younger men.
• Schedule your PSA test to be done for at least six weeks after undergoing any of the following procedures: prostate biopsy, transurethral resection of the prostate (TURP) for BPH, urethral catheter, cystoscopy, or any other procedure that involves the prostate. If you are in doubt about the possible impact of any procedure on your PSA test, talk to your doctor.
• Schedule a PSA test if you have a urinary tract infection. A bacterial infection in the urinary tract can cause PSA levels to rise temporarily. If you are not sure if you have a urinary tract infection, have a urine test before your PSA test to make sure. If you do have a urinary tract infection, you should wait at least six weeks after you have completed your antibiotic treatment before you have your PSA test.
• Schedule a digital rectal examination (DRE) before your PSA test. Although a DRE should not have an impact on PSA levels, having the PSA test first is a precaution.

Don’t forget to tell your doctor these facts if you are going to get a PSA test:

• If you undergoing chemotherapy, as these drugs can cause an elevated PSA level
• If you are taking any medications, especially statins, nonsteroidal anti-inflammatory drugs, or medications that control urinary problems such as dustasteride or finasteride. All of these substances have the potential to affect PSA levels.
• If you have undergone urinary tract or prostate surgery recently, or if you have suffered a pelvic injury or sports injury.
• If you have prostatitis or BPH.

When Should Prostate Cancer Patients Be Treated? What to Do?

Men receiving prostate cancer diagnoses and treatment have sharply increased as a result of widespread prostate cancer screening utilizing the prostate-specific antigen (PSA) test over the past 30 years. But according to current research, many men would not have been harmed by the disease, and some men's lives have not been prolonged as a result1.

With the benefits of greater screening in doubt, doctors must decide whether and how often to screen as well as what to do if cancer is found. The difficulty we currently face with prostate cancer is that we have become almost too proficient in screening, as Dr. Judd W. Moul, Director, Duke Prostate Center, Duke University Medical Center, notes.

PSA Presentation: Unlocking the Pandora's Box

According to Dr. Moul, the Director of Duke Prostate Center in Durham, North Carolina, the PSA test might produce as many questions as it can resolve. It almost appears like we're detecting prostate cancer too early in many guys, he adds, mainly because many prostate tumors don't become fatal for a very, very long time. "Screening is all about early diagnosis," he says. This "over-diagnosis" and the treatment that follows could pose excessive risk and unnecessarily lower quality of life.

A biopsy, which has risks, is required to confirm the diagnosis since increased PSA levels do not always indicate the existence of prostate cancer and because there is currently no "man mammography" to reliably assess the intra-glandular extent of a tumor. Even then, there is still some doubt because prostate needle biopsy pathology has sampling error, which could lead to an underestimation of the cancer's grade in 30–40% of cases.

PSA as a Baseline Test: A Useful Instrument

When used as a baseline test at age 40, the PSA test is unquestionably helpful for younger men. Dr. Moul notes that despite the PSA test now being included in both the National Comprehensive Cancer Network's (NCCN) and the American Urological Association's (AUA) guidelines, there is still little knowledge of and use of it in this manner (AUA). The doctor can assess a patient's future risk for prostate cancer and how aggressive or nonaggressive to be with screening over the following 10–20 years by getting a PSA value at age 40.

Active surveillance versus treatment

Physicians and patients must decide between therapy and active surveillance once a biopsy reveals malignancy. What should we do if a biopsy finds a very little cancer or an ambiguous malignancy? is a dilemma Dr. Moul struggles with. Should we risk lowering his quality of life right away or wait a little before performing a radical prostatectomy on him?

Given the paucity of reliable clinical trial data to determine therapy or identify individuals for active surveillance, there are no clear criteria for decision-making. According to Dr. Moul, "The patient's gut instinct and final decision are what matters most."

It is not nearly as frequent a strategy as active treatment because there is little agreement among doctors over the frequency and intensity of "active surveillance" and patient worry over the potential presence of the malignancy.

Dr. Moul believes that improving the active surveillance procedure for patients with early-stage illness is the way to go.

Doctors will be better able to assess when active surveillance is necessary with more robust longitudinal data.

appropriate. The best timeframe for biopsies and how closely to monitor a patient after the initial PSA test would also be clarified by further studies.

The Potential of Diagnostic Developments

To assist guide treatment or decide on a strategy for additional biopsies, a more accurate diagnosis is required. Dr. Moul hopes that an imaging test that reliably assesses the size and aggressiveness of prostate tumors will be developed because there is now no imaging test comparable to those that are available for breast cancer.

Newer generation ultrasound or MRI advancements in intra-glandular imaging may serve as a foundation for focal-gland treatments such focal cryotherapy and high-intensity focused ultrasound (HIFU). However, without such

The most promising technological advancements are those in molecular diagnostics, which are still in the works. These comprise ongoing investigations into novel biomarkers and advancements in genetic testing, including the PCA3 urine test. The clinical community will have to wait till clinical trials validate them.

Taking Care of Advanced Illness

The FDA's approval of sipuleucel-T, cabzitaxel, abiraterone, and denosumab for advanced castrate-resistant prostate cancer is one of the most recent advancements in the treatment of metastatic disease. Dr. Moul issues a warning that the availability of these new medicines and their cost have sparked discussion regarding their respective cost/benefit and the best order in which to employ them.

In this regard, the FDA-cleared circulating tumor test (CTC) may help medical professionals monitor and forecast the progression of cancer as well as assess the effectiveness of treatment in patients with metastatic disease. CTC counts have been proven to be more accurate indicators of therapy response than a drop in PSA levels in patients with metastatic prostate cancer3.

In order to help guide proper treatment, Dr. Moul emphasizes the need for more study on multi-modality and multi-disciplinary care that combines surgery with radiation or hormonal therapy. "We need to manage patients with prostate cancer that is life-threatening with the full arsenal of tools available."

References

1. The NCI Cancer Bulletin, dated September 8, 2009. http://www.cancer.gov/aboutnci/ncicancerbulletin/archive/2009/090809/page2

Prostate Cancer Facts & Figures 2010, American Cancer Society, p. 30

3. [Package insert] CellSearch® Circulating Tumor Cell Kit (Epithelial). Veridex LLC. LBL 50058, Rev. 6, 2009-05. Raritan, NJ. The document is accessible at: http://www.veridex.com/pdf/7800047 04.pdf. 11th of August 2009 access.

 

Resources and Articles:

Why Your High PSA Test May Not Be Prostate Cancer