What is a Prostate-Specific Antigen (PSA)?
The prostate gland, a walnut-sized gland located just below the bladder in men, is the only organ that produces the protein known as prostate-specific antigen (PSA). The prostate gland's primary function is to produce and secrete prostate fluid, a component of semen.
The epithelial cells are the ones that primarily secrete PSA into the prostatic fluid. Its primary function is to liquefy the semen, which facilitates the movement of spermatozoa. While PSA is predominantly present in the prostatic fluid and semen, it is also detectable in trace amounts in the bloodstream.
Prostate-specific antigen levels in the blood are typically elevated in men with prostate cancer. PSA testing measures the amount of PSA in the blood and is often used as an initial screening tool for prostate cancer. While a high PSA level blood test does not necessarily indicate the presence of prostate cancer, it can suggest further testing, such as a multiparametric MRI (mpMRI) or prostate biopsy.
However, it is essential to note that the PSA screening test has limitations and can sometimes produce false-positive or false-negative results. High PSA levels can also be caused by things that are not cancerous, like an infection, inflammation, recent ejaculation, or an enlarged prostate (benign prostatic hyperplasia).
In addition to its role in prostate cancer diagnosis, the PSA level can also be used to monitor the disease's progression and the treatment's effectiveness. A rising PSA level over time may indicate that the cancer is growing or spreading, while a decreasing PSA level may suggest that treatment is working.
It is worth noting that the use of PSA testing in prostate cancer screening is a controversial topic in the medical community due to concerns about overdiagnosis and the overtreatment of indolent (slow-growing) cancers. The UK National Screening Committee recommends against routine PSA testing. Still, it acknowledges that it may be appropriate for high-risk groups, such as men with a family history of prostate cancer, and black men.
However, data is coming out that favours prostate cancer screening.
Update on screening for prostate cancer
According to new research by Prostate Cancer UK, the UK is now in a position to implement a prostate cancer screening program. Prostate cancer screening has been demonstrated to reduce prostate cancer mortality by 20%. However, it was previously believed that the risks of screening outweighed the benefits, so it was not rolled out nationally. The study indicates that with new imaging tests (MRI scans) and safer biopsies, tens of thousands of men are spared yearly from unnecessary biopsies or sepsis during diagnosis, thus reducing the potential for harm and a better pick-up of aggressive prostate cancer.
This announcement follows the UK National Screening Committee's decision last week to review the evidence for prostate cancer screening, including population-wide screening and targeted intervention for black men or men with a family history of the disease, which are known risk factors for developing prostate cancer.
Prostate Cancer UK welcomes these decisions and urges the committee to consider all the latest evidence from the UK and Europe, supporting the case for further screening. It also highlights the need for the preventive services task force and further research in cancer screening to enhance how men are diagnosed in the early and later stages.
A study by Prostate Cancer UK looked at clinical trials, current practices, and real-world data from 16 NHS trusts in London and the southwest. It also looked at a prostate cancer screening trial that was done before more modern scans and biopsies were used. The study found a significant reduction in men experiencing harm during the diagnostic process, amounting to 902 fewer men for every 10,000 PSA tests conducted annually.
The harm reduction is primarily attributed to a decrease of almost 64% in unnecessary biopsies, resulting in 602 fewer men for every 10,000 men undergoing a PSA test. Additionally, there was a 55% decrease in men who developed sepsis. Nearly 77% fewer men were diagnosed with clinically insignificant cancer, leading to 294 fewer men for every 10,000 men undergoing a PSA test.
These findings have significant implications for prostate cancer screening programs and indicate that newer scans and biopsies have resulted in substantially fewer men experiencing harm during the diagnostic process.
In recent years, two new techniques have played a crucial role in reducing harm during prostate cancer diagnosis: multiparametric MRI scans (mpMRI) and transperineal-guided biopsies.
Before 2019, men with high levels of PSA in their blood were typically referred directly for a biopsy, which came with a risk of severe infection and could potentially miss cancer, leading to repeated biopsies. Prostate Cancer UK helped pay for research that showed using mpMRI scans before biopsies could safely stop 27% of biopsies that were not needed while also improving accuracy and making it more likely that cancer would be found during the first biopsy. The charity worked closely with the NHS to ensure this innovative technique was implemented nationwide, significantly reducing unnecessary harm.
In addition, the increased use of transperineal biopsies in recent years, which carry a lower risk of sepsis, has further contributed to reducing the risk of harm during a prostate cancer diagnosis.
In January, Prostate Cancer UK released data indicating that new screening techniques have unnecessarily harmed tens of thousands fewer men each year. However, the charity also revealed that many men are still diagnosed with stage 4 incurable cancer, with 10,000 cases reported while 12,000 die annually. These statistics underscore the critical need for a screening program that could potentially save thousands of lives.
What if my GP won't give me a PSA blood test?
This is a common situation that many men encounter. You have a right to ask for a PSA blood test.
If you have a family history of prostate cancer, breast cancer, or colon cancer, or you are of Afro-Caribbean origin, you should start doing screening tests for prostate cancer at age 45.
All other men at the age of 50 should have a PSA test and a digital rectal examination.
If the GP still refutes, then change your GP.
As a prostate cancer specialist, I fully support screening for prostate cancer, especially in the high risk group.
What is a typical PSA test result?
There are no normal PSA levels.
PSA levels should always be interpreted with other factors like age, family history, and digital rectal exam.
Based on PSA, do I have prostate cancer?
Here is an example of a general risk table for prostate cancer based on PSA level:
PSA Level (ng/mL) Risk of Prostate Cancer (%)
<2.5 ~10%
2.6-4.0 ~20%
4.1-10.0 ~25-30%
10 ~50-60%
Again, it is essential to note that these numbers are not definitive, and the risk of prostate cancer can vary depending on individual factors.
My PSA test came high. What do I need to do?
A one-off PSA value without any other test must be interpreted cautiously. Make sure you have taken the blood test correctly.
How to prepare for the PSA test
Before undergoing a PSA test, it is vital to avoid certain activities, including:
- If you have an active urinary infection (UTI), treat it and delay the PSA blood test by six weeks.
- Do not ejaculate within 48 hours before the test.
- Do not do intense physical exercise 48 hours before the test, such as cycling.
- If you had a prostate biopsy or recent catheter insertion, delay the PSA testing by six weeks.
These activities may affect the PSA test results, and it is essential to follow these recommendations to ensure accurate test results.
What is done if a screening test shows a high PSA level?
In the UK, your GP may refer you for a specialist appointment within two weeks if you have a high PSA level after a screening test.
During the specialist appointment, the NHS urologist consultant or urologist will take a detailed medical history, including any issues of how you empty your bladder and conduct a physical exam, including a digital rectal exam (DRE), to check for any abnormalities or lumps on the prostate gland.
If necessary, the specialist may recommend a multiparametric MRI (mpMRI) scan of the prostate gland, which uses different MRI scans to create detailed prostate images. This scan can identify any suspicious areas that may require further investigation. The mpMRI is usually done as an outpatient procedure and takes around 30 to 40 minutes.
If the mpMRI results are concerning, the specialist may recommend local template prostate biopsies. The results of the mpMRI guide these biopsies to ensure that any suspicious areas of prostate cancer are targeted.
The prostate biopsy is usually performed under local anaesthesia. It involves introducing an ultrasound probe through the back passage and inserting a thin needle through the perineum and into the prostate gland to obtain small tissue samples. Apart from the suspicious area, random biopsies of the prostate are taken. These prostate tissue samples are sent to a lab for examination under a microscope.
Patients may experience discomfort during and after the biopsy, which can usually be managed with over-the-counter pain relievers.
Not all patients with high PSA levels will require a biopsy. Deciding to proceed with a biopsy will depend on several factors, including the PSA level, imaging test results, and individual patient factors.
What increases the risk of prostate cancer?
- Age: The risk of prostate cancer increases with age, with most cases occurring in men over 50.
- Family history: Men with prostate cancer have an increased risk of developing the disease, especially if their father or brother was diagnosed before age 60.
- Ethnicity: Prostate cancer is more common in African American men and less common in Asian and Hispanic men.
Those with a strong family history of cancer should be referred for genetic testing.
Regular PSA test
If you have high-risk factors for prostate cancer, you should check your PSA on a minimum-yearly basis. Some men prefer a six-monthly check, which is also acceptable. There is no such research on prostate cancer PSA testing frequency.
What prostate cancer treatment is available?
According to the National Institute for Health and Care Excellence (NICE) and the National Comprehensive Cancer Network (NCCN), prostate cancer treatment depends on the stage (early stage Vs late stage) and patient fitness. The treatment should always be balanced with the risk factors each treatment for prostate cancer carries, like urinary incontinence, erectile dysfunction and others.
Prostate cancer early detection
- Active Surveillance
- Radical prostatectomy
- Radiation therapy and Hormone Therapy
- Focal treatments like high-intensity focused ultrasound (HIFU), NanoKnife and Cryotherapy
Prostate cancer late detection (prostate cancer that has spread)
- Watchful Waiting
- Hormone Therapy
- Novel Treatment (Enzalutamide, Abiraterone, Darolutamide, Olaparib)
- Chemotherapy
Reflection from a prostate cancer doctor
Prostate cancer screening, especially in those with higher risk factors, has decreased prostate cancer mortality and identified those men with early stages of prostate cancer.
The PSA test, combined with the prostate health index, PSA velocity, prostate biopsy, MRI scan, and other tests, form part of the armamentarium to diagnose prostate cancer.
