The co-authors of Invasion of the Prostate Snatchers, blog alternate posts weekly. We invite you to post your comments.

Tuesday, December 30, 2014

PSA, The Human “Check Engine” Light


Why all the controversy about PSA? How can people fault a simple blood test that uncovers cancer at an early stage? The problem is that the PSA test doesn't specify what type of cancer the patient has. In addition to the presence of cancer, there are two other common causes of PSA elevation—prostate gland enlargement that comes with age, called BPH, and chronic prostate inflammation, called prostatitis.

PSA by itself doesn’t diagnose prostate cancer.  It is a nonspecific indicator, like the “check engine” light on the dashboard of your car.*  Does this eliminate the value of PSA?  Of course not.  An elevated PSA reading is a useful indicator of the need for further research into the cause.

The biggest fear--and the primary argument used by PSA naysayers--is that so many urologists recommend immediate random biopsy with any PSA elevation whatsoever.  A million men are biopsied annually in the US, resulting in the over-diagnosis of innocuous prostate cancers in about 100,000 men each year.  Most of these men end up undergoing unnecessary radical surgery or radiation.

So how do we eliminate the bathwater (random biopsies) without throwing out the baby (PSA)?  The first step is avoiding the trap of rushing headlong into something before learning the whole story. Since we know PSA is nonspecific, most elevations will be from prostate enlargement, not cancer.  PSA needs to be interpreted in relation to prostate size.

One might think that only ultrasound or MRI can reliably measure prostate size.  And while imaging is indeed the most accurate method, practiced doctors can roughly estimate prostate size with a simple digital prostate exam.  Also, there is a PSA blood test variant called “free” PSA that is suppressed in men with BPH.  Free PSA is reported out as a percentage of total PSA.  When free PSA percentage drops below 10%, BPH as a cause for PSA elevation is less likely.

Sequential PSA testing is the best way to diagnose inflammatory prostatitis, the other common reason for benign PSA elevation. Inflammation can increase PSA, which often oscillates up and down as the inflammation in the gland waxes and wanes.  This bouncing PSA pattern is in sharp contrast to an elevation of PSA caused by cancer.  A rise in PSA from cancer is usually unidirectional—up, up and up.

Historically, despite the drawbacks from biopsy of over-diagnosis, infections and discomfort, it has been the gold standard for diagnosing prostate cancer. Only very recently have new advances in multiparametric MRI imaging enabled men with PSA elevation to consider this imaging alternative--rather than random biopsy--as a first step. Our recommendation to use a multiparametric MRI (at a center of excellence) followed by a targeted biopsy if a suspicious lesion is detected, has been discussed in more detail in previous blogs. 

*I wish I could take credit for the check engine light idea that so nicely conveys the useful but nonspecific character of PSA.  This little pearl of knowledge was passed on to me by a patient. 


Anonymous said...

I completely agree with the PSA test as a valuable non-specific indicator. I am appalled that some insurance lobbyists are pushing to extend routine PSA test to 55 years and later. I am 48 and had no symptoms at all, but a PSA test by an thorough physician found aggressive prostate cancer that was right to the margins and ready to break free. I believe PSA test should be routinely done on much younger men (40s?) but should be used for what it is a "Check engine light"

Anonymous said...

Slow, steady increase in my PSA for 20 years. 2012 3.5 2013 4.5. Nothing to worry about, even though my Dad lost a 3-year fight with prostate cancer, was what my PCP stated. Feb 2014 no PSA test then because of a change of national protocols. Had it checked by a urologist 14.32 in August, subsequent biopsy showed "advanced, aggressive" cancer in 12/12 cores. Yes, I did allow a surgeon snatch it.
Do I recommend PSA tests? Absolutely. My 24 yo son will get a regular one, even if I have to pay the $50 for it or $80 for a free P
SA test.

Anonymous said...

I agree emphatically with the 2 "anonymous" posters.
But I have a question about the confusing statement "The problem is that the PSA test doesn't specify what type of cancer the patient has."
What does this mean? Pls explain. Shouldn't it read ". . .doesn't specify WHETHER the patient has PCa"?
Thank you.

Anonymous said...

Just another fan of the PSA test checking in with my experience.

Always had a low (under 3) slow rising PSA and a "normally enlarged" prostate until age 71. At age 72 it went up to 5.9. At "your age" nothing to worry about according to my PCP. I hated hearing the "at your age" part and independently went for another PSA after sweating for 8 months and found it at 11.9. I had my primary refer me to a urologist who suggested but did not insist (again, "at your age" it is probably okay to wait watchfully) I do the random 12 core biopsy. I said "go for it" and biopsy showed 7 cancerous cores all with Gleason scores of at least 6 and 3 with Gleason scores of 7 (4+3 variety). By this time I am 73 years old and very nervous. Subsequently all scans showed no break out of cancer from capsule so I found a skilled Da Vinci surgeon and had a radical prostatectomy. I'm 74 now, strong healthy and the after effects of the surgery are very minimal and manageable. My PSA so far has been non-detectable.

Start young, keep up with your PSA and don't let AMA protocols based on age (young or old) deter you. I have seen four of my friends die of prostate cancer, three because they watchfully waited after PSA jumps and the fourth because he never did the first PSA.

Henry Franklin said...

As you state the PSA test is a non-specific test that does not diagnose PC. but is only an indication of a problem that needs further investigation.
This is also the case with all other cancer test, a Mamogram for breast cancer only detects a lump which may or may not be cancer that needs further tests to actually diagnose cancer.
The same applies to both a pap smear and an FOBT test for bowel cancer. My question is as to why there is only a debate about the PSA test for PC? could it be that Prostate Cancer only affects Men??????????????

Prostate Oncology Specialists said...

@anonymous: The problem is that the PSA test doesn't specify what type of cancer the patient has." ^^ and shades found here:
videos are helpful. "Following that of course, there are different methods of monitoring - some centers use regular biopsies, frequent PSA testing, and different types of thresholds for deciding who has the type of cancer that does need treatment. I won't go into that at this point, because that is a complex area, but the first and most important take home message is that this idea -- it's safe to watch certain types of prostate cancer is an established medical fact. Some doctors, unfortunately are still unaware of this fact."

Bryan said...

Yes I agree. 49 here. For years tod don't do PSA until 50, even tho my dad had prostate cancer. Last annual visit I was offered option and said ok do it even tho totally non-symptomatic. While physical exam of prostate was normal PSA was very high (like 12). This led to follow up with specialist and biopsy that was thankfully negative although so atypical cells to monitor.

I can say to any guy possibly confronting a biopsy that it is nothing to worry about. Please don't avoid it because it is just not that bad. Honestly.

I was afraid of results and lucked out at least for now. But either way at least you know if you have it done. And if it is something you get it as early as possible. And if not you have a baseline.