Prostate Cancer Screening: What the PSA Test Can and Cannot Tell You

What it involves

MedlinePlus explains that prostate cancer screening looks for signs of cancer in the prostate, a gland below the bladder that makes fluid for semen, before any symptoms appear. Two tests are commonly used: the PSA blood test, and the digital rectal exam, in which a provider feels the prostate for lumps.

Who this is for

• Men in their 50s and 60s deciding whether a PSA test is right for them
• Men under 55 with a father or brother who had prostate cancer
• African American men, who MedlinePlus says have a higher risk and may develop prostate cancer at a younger age
• Men with a weak stream or frequent night trips who wonder whether the prostate is the cause

What to expect

• A conversation about your age, family history, race and general health, the factors MedlinePlus says to weigh
• A plain explanation of the possible benefits and harms before any test is ordered
• A blood draw for the PSA test if you decide to go ahead, with the result reviewed in context
• A referral to a urologist if the result or exam calls for more testing, such as a repeat test or a biopsy

Why this is a shared decision

MedlinePlus says it is not clear whether early detection and treatment lower the risk of dying from prostate cancer, and that prostate cancer usually grows slowly and may never cause health problems. The goal of screening is to find the cancers more likely to spread so they can be treated early. Because there are benefits and risks, it advises talking with your provider to decide whether screening is right for you, instead of following one rule for everyone.

What the guidance says about age

The encyclopedia notes that for some men 55 through 69, screening may help reduce the chance of death from prostate cancer, while for many men screening and treatment could be more harmful than helpful. It adds that the US Preventive Services Task Force recommends against PSA-based screening in men 70 and older. Men younger than 55 with a higher than usual chance, such as a father or brother with prostate cancer or African American men, should talk with a provider about it. The preventive screenings by age guide shows where it sits among other screenings.

What a PSA number means

PSA is a protein made by the prostate. The encyclopedia says a normal level is considered up to 4.0 nanograms per milliliter, with most men in their 50s or younger below 2.5, and that older men often have slightly higher levels. A high number is linked to a greater chance of cancer but is not proof, and a low number is not a guarantee. An enlarged prostate, an infection, a recent bladder test or catheter, recent ejaculation and a recent colonoscopy can also raise it. The enlarged prostate guide covers the most common benign cause.

Possible benefits and harms

MedlinePlus lists the benefits as finding and treating cancer early, a better sense of your risk, peace of mind after a low result and the option of closer monitoring. The harms include a false positive that causes worry and may lead to a biopsy, with possible fever, pain, blood in the semen or a urinary tract infection, and treatment you may not have needed. Common treatments can have permanent complications such as urinary incontinence, erectile dysfunction and trouble controlling bowel movements. Weighing those against your own preferences is the purpose of the conversation.

Getting ready for the blood test

The encyclopedia says no special preparation is usually needed, but you should tell your provider about every medicine you take because some can make the PSA falsely low, and you should not have the test soon after a urinary tract infection or a procedure on the urinary system. The draw itself is a routine blood draw with a small prick. The blood work preparation guide explains when fasting does and does not matter for other tests.

After an abnormal result

MedlinePlus says a provider considers your age, earlier PSA results, how fast the level has changed, whether a lump was felt on the exam and your other risk factors. Men at higher risk may repeat the PSA test, most often within three months, sometimes after an infection is treated first, or have a free PSA test, an MRI of the prostate or a biopsy if the level stays high or keeps rising. Those steps are arranged by referral. Men who notice trouble urinating can read the frequent urination guide first. Prostate treatment can sometimes affect erections, and men who already have trouble can read the erectile dysfunction guide, while the annual physical page for Wellington patients explains what a yearly checkup covers for men weighing screening.

Sources

• MedlinePlus: Prostate Cancer Screening (health topic)
• MedlinePlus: Prostate-specific antigen (PSA) blood test (medical encyclopedia)