The most common cancer affecting men is prostate cancer. It is estimated that 80% of men will have prostate cancer by age 80. It is often also said that more men die with prostate cancer than because of prostate cancer because it is usually a very slow growing cancer. However aggressive forms do exist and thus prostate cancer is the 3rd leading cancer killer of men.

Prostate cancer screening becomes an important health concern for men as they age. Prostate cancer screening is accomplished by a combination of PSA + DRE (see below). There is a lot of controversy with regards to screening for prostate cancer, so we will investigate this during the next few articles. Let’s start with the basics.

What’s the prostate?

The Prostate Gland

The prostate is a part of the male reproductive system. It is made up of glands, which produce the fluid component of semen (the sperm are made in the testicles). Androgens, a group of male hormones, including testosterone, are responsible for signaling the prostate to do it’s job.

The prostate is found just below the bladder, surrounding the urethra (the tube that carries urine and semen out of the body). It is also directly in front of the rectum (part of the colon). The anatomic location of the prostate explains why problems involving the prostate typically affect urination and ejaculation.

What’s PSA?
PSA stands for prostate specific antigen. It is a protein that is made exclusively by the prostate gland and excreted into the blood (so it’s just a simple blood test). An elevated PSA means that the prostate is working harder than normal, which can be caused by a few different conditions. The most worrisome condition is prostate cancer. However, inflammation or infection of the prostate (called prostatitis) and benign prostatic hyperplasia (BPH) can also cause elevations in PSA. The normal total PSA level is between 0 and 4 ng/mL. Essentially, the PSA gives us a way to see how the prostate is working, with elevations showing that for some reason the prostate is working “too hard.” Then we need to figure out why.

It is very important to mention two things.  First, it is recommended that the PSA level be double checked if elevated as lab errors do happen.  The test is cheap and easy to repeat.  Second, trauma, antibiotics, and most importantly certain medications can affect PSA levels.  Specifically, a class of drugs called 5a-reductase inhibitors (Proscar, finasteride, dutasteride, Avodart), typically used to treat BPH, can falsely lower your PSA.  Please be sure your doctor knows if you are on any of the medicines!

I’ve heard about total PSA and free PSA – what’s the difference?
Well, both can be measured. When we talk about the PSA protein, think of it as a sticky piece of gum. Because it’s sticky, when it’s secreted into the blood it sometimes attaches to other proteins that are also floating around. Because of this, PSA then exists in 2 forms, stuck to other proteins or just by itself. The portion of PSA that exists all alone is the free PSA. The total PSA measure the total amount, so both the free and bound forms of the molecule.

The typical test ordered for screening is a total PSA. Free PSA is usually only ordered if there is a moderate elevation of the total PSA and the doctor wants a bit more information.

What’s DRE?

The Rectal Exam

DRE stands for digital rectal exam. This is an exam maneuver performed by your physician in the office. He or she inserts his/her lubricated index finger into your rectum to feel the prostate gland. Your physician will feel for lumps, bumps, firmness and tenderness. This is rarely painful, but it is a bit uncomfortable. It should only last about 10 seconds. Additionally, the physician is also screening for rectal cancer by feeling for any lumps or bumps in your rectum. So while the exam may be uncomfortable, you are being screened for two of the most common cancers that affect men!

Part 2: The Controversy Behind Prostate Cancer Screening

For more information:

http://www.labtestsonline.org/understanding/analytes/psa/test.html