The sensitivity of the PSA test as an indicator of the presence of prostate cancer is known to be about 80 to 90 percent. In lay terms, what this means is that 80 to 90 percent of men who actually have prostate cancer cells in their prostate will have an elevated PSA level compared to men who show no sign of prostate cancer after having at least one biopsy. (Why 80 to 90 percent? Because it depends where you draw the cut-off line for an “elevated” PSA level — at 4 ng/ml or at 3 ng/ml, or at 2.5 ng/ml. The lower the cut-off line, the higher the sensitivity.)
The selectivity of the PSA test is about 50 percent. In lay terms again, this means that an elevated PSA level (again compared to PSA levels of men who show no sign of having prostate cancer after at least one biopsy) is a complete toss-up. You could have some prostate cancer cells … but you could just as easily have none.
According to an article on ther Medscape web site, Pincus et al. have now reported (in a presentation at the annual meeting of the American Society for Clinical Pathology) that the sensitivity of a first prostate biopsy is about 80 percent. In other words, 80 percent of men with prostate cancer cells in their prostate will have a positive biopsy at their first attempt (and 20 percent won’t). They also report that 100 percent of men in their cohort who had a PSA level of 40 ng/ml or higher had a first biopsy that was positive for prostate cancer.
Now let us be very clear indeed. Having some prostate cancer cells in your prostate and having a clinical condition called prostate cancer are not the same thing. To have the clinical condition, you must have prostate cancer cells in your prostate. But having prostate cancer cells in your prostate may not have any clinical significance at all. Why is this important?
It is important because Dr. Pincus and his colleagues have used a circular argument to justify their opinion that “PSA is an excellent marker for prostate cancer, since it has a similar sensitivity to a first prostate biopsy and is less invasive with less risk of morbidity.” What? Say that again!
OK. Let’s say that again — this time in English … Dr. Pincus is arguing that because a prostate biopsy has an 80 percent specificity for finding prostate cancer cells in the prostate, and 80 to 90 percent of men who actually have prostate cancer also have an elevated PSA, then PSA is “an excellent marker for prostate cancer.” The problem, of course, is threefold:
- 50 percent of men with an elevated PSA level still don’t have prostate cancer.
- Of the 50 percent of men who do have an elevated PSA level, about 30 percent who have a subsequent positive biopsy will have clinically insignificant disease which may now get treated unnecessarily.
- And the suggestion that the PSA test is “an excellent marker ” is in comparison to a first biopsy. Is anyone seriously suggesting that we should just biopsy every man in America when he hits 40 (0r 50 or whatever) years of age?
Only a pathologist could think like this. It ignores the entire reality of whether the man considering his potential risk for prostate cancer has a right to an opinion on the subject.
The research team carefully points out that 96 percent of the 1,665 patients at the Veterans Administration New York Harbor Health Care System on whom their data are based and who were found to have prostate cancer (cells in their prostates) on biopsy underwent biopsy only because of an elevated PSA level! That means that (presumably) about half these men had a first biopsy because of an elevated PSA level, and that their first biopsies were all negative (even though 20 percent of them were false negatives). Of course there are no data provided about whether even one of those patients who had a negative biopsy got a serious systemic infection or worse still died as a consequence of such an infection — but that is well within the limits of probability.
If there was ever a study that clearly demonstrated the need for a much better test to assess the risk of clinically significant prostate cancer, this was that study.
The “New” Prostate Cancer InfoLink does not believe that the PSA test is a “bad” test or that it shouldn’t be used. We also do not think that people shouldn’t get biopsies. But we do believe that it’s high time to stop pretending that the PSA test is the test we need. It is simply the test we have. It needs to be used with caution. Subsequent biopsies should also be used with caution. We need to find a much better test just as soon as we possibly can! And we need to be a great deal clearer in our heads that having some prostate cancer cells in our prostates is not necessarily the same as having the clinical condition formerly (and formally) known as prostate cancer.
Filed under: Diagnosis, Risk | Tagged: biopsy, Diagnosis, PSA, risk |
THE "NEW" PROSTATE CANCER INFOLINK 
Sitemaster got it. Or almost got it.
It is absolutely true we would like to have a better test with high sensitivity and specificity that will detect all cases of prostate cancer (no false negatives) and only cases of prostate cancer (no false positives). Such a test would be the ultimate test and will totally nullify the need for pre-treatment biopsies.
Alas, such a test is not available yet and therefore it is absolutely necessary to have an yearly PSA test that needs to be followed by a biopsy, if the PSA level is high.
Are PSA and biopsies 100% correct? No, but in the absence of a better test they are the only choice we have and we should vigorously promote PSA testing.
I have had two biopsies taken by the VA, both were negative, the first taken in about 1992 when my PSA was discovered to be about 5.5; the second taken in 1998 when my PSA was about 9.5 — also negative. My PSA has varied between 9.0 and 11.5 since the last biopsy. I have been seen yearly by Dr Duke Bahn in Ventura, CA, who uses a color contrast Doppler scan of the prostate and so far my prostate shows no distinct signs of “prostate cancer.” Dr Bahn does state that I have a very large prostate, one of the biggest he has evaluated. He always asks if I want a biopsy and I always decline because so far I do not retain any residual urine after urinating and my symptoms of BPH are not intolerable. I do take Super Beta Prostate formulated by biochemist Roger Mason for the past 11 years and seem to be doing fine. When I mention this fact to any urologist they just raise their eyebrows and don’t comment at all? WTFO?
Sincerely,
Frank J. Navratil
Sitemaster wishes to be very clear that (in Reuven’s terms) he doesn’t “got it” at all. He does not agree with Reuven’s postulate that “it is absolutely necessary to have an yearly PSA test.” Indeed, he suspects that this is a waste of time and money and potentially highly risky for an awful lot of men with absolutely no known risk of prostate cancer at all. Such men may be wiser to have a PSA test about once every 5 years or so at age 40 and thereafter to assess their baseline PSA level.
I was surprised to see this:
50 percent of men with an elevated PSA level still don’t have prostate cancer.
I do not recall having seen a reasonable study that demonstrated more than a 35 per cent positive result in men with an elevated PSA – and that usually with a high number of needles (12 plus) or with repeat biopsy.
Any idea where the 50 per cent came from?
Terry:
The 50% was the number reported by the researchers in this specific study (see the Medscape article). I would agree with you that that may well be high, and that the negative biopsy rate for men with an “elevated” PSA level of 2.5 or 3.0 ng/ml is probably more like 65% in the general population of men aged 50 years or older. Of course 50% is also the specificity quoted by our good friend Dr. Ablin. How could I quibble?
:O)
Hi Sitemaster. I’m responding to your comment of November 12, 2010 at 10:48 am in which you said in part that you suspect that:
“… an yearly PSA test … is a waste of time and money and potentially highly risky for an awful lot of men with absolutely no known risk of prostate cancer at all. Such men may be wiser to have a PSA test about once every 5 years or so at age 40 and thereafter to assess their baseline PSA level.”
Agreed, there is clearly a risk of unnecessary biopsies and overtreatment stemming from annual PSA testing. I’m convinced this risk becomes negligible for men who understand that not all suspect PSAs need biopsy follow-up and that low-risk prostate cancer very likely does not need treatment, with active surveillance capable of revealing the wise course.
For such savvy men, annual testing makes sense to me. Annual testing can reveal important clues about PSA velocity, which ties in to prostate cancer, infection and BPH. Without annual testing for patients who are diagnosed with prostate cancer, the patient lacks the clue whether his PSA velocity was greater than 2.0 or not in the year before diagnosis, which at least two studies have confirmed as important in assessing the seriousness of the case. (Note that such a rise can be due solely to infection, which would signify nothing about prostate cancer.) All that said, men with extremely low PSAs can probably safely skip every other year, based on research.
I certainly recognize that you have a basis for favoring a more relaxed kind of screening, but, having to make a choice in the context of uncertainty, I’m recommending annual screening to my sons. I would be recommending that even if my diagnosis wasn’t an added risk factor for them.
Ah … but Jim … your diagnosis has inevitably colored your perspective … and therefore the recommendation to your sons. I’m not saying it is right or wrong, just that your experience is critical to your recommendation. The question I would ask is whether people think your recommendation to your sons would be the same if it had been colored by significant adverse effects after first-line treatment for a low-risk (PSA < 10 ng/ml, Gleason 6, single positive biopsy core) in (say) your mid to late 40s or early 50s — and no further disease progression.
Dear Sir,
PSA testing, with its excessive rate of false positives, is making healthy men into patients. The test is hardly specific and single test results are not to be trusted. Even riding a bicycle to the blood test may raise your PSA outcome!
Try comparing a prostate biopsy to doing a similar test to women with (only) an increased risk of breast cancer. It’s just 12 needles madam! Wouldn’t fly I think.
PSA testing and biopsies are only slightly better than grasping in the dark, in my view (a PSA tested and twice biopsied “patient”), and should not be in any regular screening without corrobating indications.
My husband was just diagnosed with stage II prostate cancer. His Gleason score was 6; T1c (which I don’t understand at all); 5 of 12 biopsy cores showed from a trace to one core at 100%. He is under 40. What confuses me is just exactly how do we know what is or is not slow-growing cancer. All treatment choices are horrific.
Dear Anne:
Please join our social network, where we can help you to understand possible answers to the questions you are asking in the case of your husband specifically.
My brother (age 62) had a PSA test score of 12 and a biopsy showed nil cancer. The urologist congratulated him and advised to take Duadart capsules (one daily for 2 months) and then see him again. What does the urologist want to ascertain and why he has given my brother this capsule?
Dear Anwer:
It seems likely that your brother has a very common condition among men in their 60s that is known as benign prostatic hyperplasia — basically enlargement of the prostate. The Duadart should help to shrink your brother’s prostate down to a more normal size, lower his PSA level, and help to improve any problems that your brother has been having with urination.
The urologist wants to see him again in 2 months to check and make sure that the Duadart has, in fact, been having the desired effects.
Dear Sir,
Thank you very much for giving expert opinion with clarity. God may bless you.
Regards
Anwer Arain