PSA stands for prostate-specific antigen. It is an enzyme produced by prostate cells that is concentrated in semen to help liquefy it after ejaculation.
Higher levels of PSA can be found in the blood stream if there are disruptions in the barrier between prostate cells and the blood stream.
Although elevated PSA can be due to non-cancerous causes, PSA screening is used because it can also be an early indication of prostate cancer. The goal of screening is to detect prostate cancer while it is still in its early stages and men are still able to be cured with treatments
PSA screening test if not perfect. There are sometimes low numbers in men with cancer and high numbers in men without it. However, it is used because it has proven to save lives. The most commonly used threshold to define elevated PSA is 4 ng/ml. Other abnormal PSA values can include a PSA over 2 ng/ml in men on medications such as finasteride or dutasteride for balding or urinary symptoms or a PSA below 4 ng/ml in a younger man if the PSA is high for his age group.
Prostate cancer deaths were decreased by about 40% in the decades following the introduction of PSA screening. Randomized studies of PSA screening have shown a benefit similar to mammography screening for breast cancer. This includes a 20% reduction in deaths caused by prostate cancer and a 33% reduction in cases of metastatic prostate cancer after 10 years of screening.
Because prostate cancer typically has a long natural history, the majority of screening benefits are obtained after 10 years or more. So men with life expectancies less than 10 to 12 years should not undergo screening because they are unlikely to benefit.
Most guidelines recommend obtaining regular PSA levels in men between the ages of 55 and 70 with good life expectancy. Men between the ages of 40 and 54 with risk factors for prostate cancer, including a family history or African ancestry, may be screened at an earlier age.
Causes and Risk Factors
Many non-cancerous things can cause elevated PSA in the blood such as natural increases in prostate size with aging, prostate inflammation, recent instrumentation, recent ejaculation or cycling, and urinary tract infections. A family history of prostate cancer and African ancestry are risk factors for prostate cancer.
When to Speak with a Urologist about Elevated PSA
You should talk to a Urologist about an elevated PSA level if your PSA level is rising rapidly (more than 0.35 ng/ml increase per year) or if your PSA level is over 4 ng/ml. You should also seek evaluation if your PSA level is over 2 ng/ml while taking medications such as finasteride or dutasteride for balding or urinary symptoms.
What to Expect when Seeking Treatment
In addition to a history and physical examination with digital rectal exam, initial assessment typically includes urine testing to rule out infection and repeat blood work to confirm PSA elevation. A process of shared decision making will take place between the patient and physician regarding the risks and benefits of proceeding with definitive testing by undergoing a prostate needle biopsy. Prostate needle biopsy to obtain prostate tissue is the only available proven method of diagnosing prostate cancer.
Prior to testing for the presence of prostate cancer, it is important to understand that there are many different types of prostate cancer including low risk types that may require no additional treatment beyond close monitoring while higher risk types can be cured with surgery or radiation.
The risk of a positive biopsy can be estimated based on comparing a patient’s clinical factors to those of a large study population with known outcomes. Commonly used prostate cancer risk calculators include the Cleveland Clinic risk assessment tool and the Prostate Cancer Prevention Trial risk assessment tool.
A prostate biopsy is the only definitive method for testing for the presence of prostate cancer although it is known that the standard approach to prostate biopsy may miss a prostate cancer even when present about 30% of the time. So continued follow-up is important even with negative findings. Although prostate MRI is improving and useful in certain circumstances, it is not currently recommended prior to initial biopsy.
The prostate biopsy is conducted with ultrasound guidance and generally does not require anesthesia. The ultrasound probe is passed into the rectum to take measurements of the prostate then to guide needle core samples of 12 areas around the prostate after the injection of local numbing medication. The entire procedure takes about 10 minutes. The pathology results are typically returned in one week.
To limit infection risk, antibiotics are prescribed before the procedure and certain individuals with higher likelihood of colonization with antibiotic resistant bacteria will have additional antibiotic injection (recent antibiotic use, healthcare workers, recent foreign travel). To limit bleeding risk, blood-thinning medications should be held after obtaining clearance from the prescribing doctor. The risks of the procedure include about a 50% chance of minor blood in the urine, stool and semen for up to 6 weeks and a 2% chance of temporary difficulty urinating, serious bleeding or serious infection.