Understanding Prostate Cancer Numbers

There are several numbers you’ll encounter as you travel on your journey through prostate cancer. The first will be your PSA or Prostate Specific Antigen number. As a side note, contrary to the “Prostate Specific” in the name, minor amounts may be produced in the pancreas or in salivary glands. However, by far most PSA is generated in the prostate.

PSA generation has 2 main causes:

1. Prostate cancer
2. Irritation of the prostate

Things that can irritate the prostate and cause PSA generation include prostate infections (prostatitis) and activities that physically pressure the prostate.

In order to rule out prostatitis, your urologist may prescribe a course of antibiotics. After you’ve completed the antibiotics, you’ll get another PSA test. If your PSA drops back into the acceptable range afterwards, you and your urologist may decide to wait several months before checking PSA again.

Other things that may irritate your prostate and cause PSA to rise are Benign Prostatic Hyperplasia (BPH/enlarged prostate), or recent ejaculation. Another common cause of prostate irritation in some men is bike riding. You’ll want to refrain from biking and ejaculation for several days prior to a PSA test.

Here are some guidelines for PSA levels from the Prostate Cancer Foundation:

• Age 40-49: Typically below 2.5 ng/mL.
• Age 50-59: Typically below 3.5 ng/mL.
• Age 60-69: Typically below 4.5 ng/mL.
• Age 70+: Often, levels up to 6.5 ng/mL may be considered within normal limits.

Talk with your urologist about whether your PSA level is appropriate for your age and physical condition.

If you and your urologist decide that your PSA level is suspiciously high, the next step in your journey will probably be an MRI – Magnetic Resonance Imaging. An MRI can give your urologist an idea of whether there are areas of your prostate that might be cancerous.

The MRI will result in the next set of numbers that will help determine whether your prostate harbors some cancer – the Prostate Imaging - Reporting and Data System (PI-RADS). PI-RADS is a standardized scoring tool for evaluating possible cases of prostate cancer. It was developed to improve the prostate cancer diagnosis process, reducing the number of unnecessary biopsies. Coincidentally, one of the doctors on the team that developed the PI-RADS scoring system works at the University of Cincinnati Hospital – Dr. Sadhna Verma.

The purpose of getting a prostate MRI is to assess the likelihood that prostate cancer is present. This will help you and your doctor decide whether a biopsy is necessary. And, if the decision is that a biopsy is necessary, the MRI will give an idea of which area(s) of the prostate should be targeted.

Here is the PI-RADS rating system:

PI-RADS 1: Very low risk (clinically significant cancer highly unlikely).
PI-RADS 2: Low risk (clinically significant cancer unlikely).
PI-RADS 3: Intermediate/Equivocal risk (unclear if significant cancer is present).
PI-RADS 4: High risk (significant cancer likely).
PI-RADS 5: Very high risk (significant cancer highly likely).

A PI-RADS score of 1 or 2 may lead you and your doctor to conclude that a prostate biopsy is not needed, thus avoiding the risks and discomfort that comes with a biopsy. On the other hand, a PI-RADS score of 4 or 5 will likely lead you and your doctor to proceed to getting a biopsy.

Here’s an excerpt from an MRI report:

Lesion #1: Right peripheral zone apex posterolaterally.
Size: 1.3 x 0.7 cm (series 650, image 35).
ADC: Mild/moderate hypointense.
DWI: Iso/mild hyperintense.
DCE: Focal Enhancement. PI-RADS 4.

Notice the last line of the report: PI-RADS 4. This indicated that significant cancer was likely to found in the right peripheral zone apex of the prostate. This meant a biopsy was the proper next step.

Biopsy is the “gold standard” for determining whether cancer is present not only for prostate cancer but for almost all forms of cancer. A biopsy consists of taking a sample of the tissue suspected of being cancerous and then subjecting that sample to a test that’s been proven to determine whether cancer is present and, in some cases, determining how serious that cancer is.

So now we come to the next set of numbers you’re likely to encounter: The Gleason score.

Developed by Dr. Donald Gleason in the 1960s – 1970s for the Veterans Administration, the Gleason score is a system used to grade prostate cancer based on the microscopic architectural pattern of cancer cells, ranging from 1 (most differentiated) to 5 (least differentiated).

That is, a pathologist trained in recognizing the 5 patterns examines the samples taken from the biopsy. For each sample, the pathologist identifies the most frequently occurring pattern. This becomes the first number in the Gleason score. Then the pathologist identifies the next most frequently occurring pattern which becomes the second number in the Gleason score. Adding these two numbers gives you a single Gleason score. In practice today, ratings 1 and 2 are not used. Thus, a Gleason score ranges from 3 + 3 = 6 to 5 + 5 = 10.

This system is simplified by the “grade group (GG)” 1 to 5 scale as follows to help patients understand risk level:

GG1 – low risk (Gleason score 3+3=6)
GG2 – favorable intermediate risk (Gleason score 3+4=7)
GG3 – unfavorable intermediate risk (Gleason score 4+3=7)
GG4 – high risk (Gleason score 4+4=8)
GG5 – high risk (Gleason score 9 or 10)

Here’s an excerpt from a prostate biopsy report:

H. Prostate, right medial mid, biopsy:
- Prostatic adenocarcinoma, estimated Gleason score 3+3=6 (grade group 1).
- Carcinoma involves 10% of one of one (1/1) core.

This snippet tells us that:
1. The sample’s Gleason score is 3+3=6
2. The Gleason score translates to grade group 1 – low risk.
3. The part of the sample taken that was cancerous was 10%. Thus, 90% of the sample was NOT cancerous, another indication of low risk

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