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Prostate biopsy--false negative?
  1. #1
    Steven L. Guest

    Default Prostate biopsy--false negative?

    I have read that prostate biopsy involves about a 25% rate of false
    negatives. That is, in 25% of negative biopsies, it turns out that the
    patient has prostate cancer after all.

    What is current medical practice regarding when a second prostate biopsy
    is warranted, to make sure that the first biopsy was not a false negative?

    I ask this because I had a prostate biopsy 14 months ago, which was
    negative for cancer. But since that time, I've started experiencing
    kidney failure too, indicative of a rapidly worsening prostate
    situation. That doesn't sound very "benign" to me.


    --
    Steven L.
    Email: [email protected]
    Remove the NOSPAM before replying to me.

  2. #2
    Steve Jordan Guest

    Default Re: Prostate biopsy--false negative?

    On August 14, Steven L. wrote:

    > I have read that prostate biopsy involves about a 25% rate of false
    > negatives. That is, in 25% of negative biopsies, it turns out that the
    > patient has prostate cancer after all.


    If I interpret what S has written, he says that 25% of biopsies report
    that there are no PCa cells when there actually are PCa cells in the
    prostate.

    Sounds to me as if the biopsy simply missed areas that included PCa.
    That's why the "sextant" biopsy, which takes only six specimens, is
    considered by educated uros to be unreliable. Some uros take 8
    specimens. Others take more.

    Duke Bahn, MD, uses CDUS (color doppler ultra-sound) exams to determine
    which areas should be targeted for biopsy.

    > What is current medical practice regarding when a second prostate biopsy
    > is warranted, to make sure that the first biopsy was not a false negative?


    Seems to me that a continued rise in PSA, as well as other out-of-limits
    tests that all too many uros ignore, would give the patient and an alert
    medic notice that it's time to redo a biopsy.

    > I ask this because I had a prostate biopsy 14 months ago, which was
    > negative for cancer. But since that time, I've started experiencing
    > kidney failure too, indicative of a rapidly worsening prostate
    > situation.


    Um, who, exactly, says that kidney failure is "indicative of a rapidly
    worsening prostate situation?" And is the "prostate situation" supposed
    to be cancer?

    Precision in language would be helpful.

    I do not intend to be combative or disrespectful.

    Regards,

    Steve J

  3. #3
    Alan Meyer Guest

    Default Re: Prostate biopsy--false negative?


    "Steven L." <[email protected]> wrote in message
    news:54qdnS-g[email protected]..
    >I have read that prostate biopsy involves about a 25% rate of
    >false negatives. That is, in 25% of negative biopsies, it turns
    >out that the patient has prostate cancer after all.
    >
    > What is current medical practice regarding when a second
    > prostate biopsy is warranted, to make sure that the first
    > biopsy was not a false negative?
    >
    > I ask this because I had a prostate biopsy 14 months ago, which
    > was negative for cancer. But since that time, I've started
    > experiencing kidney failure too, indicative of a rapidly
    > worsening prostate situation. That doesn't sound very "benign"
    > to me.


    Steven,

    I'm not a doctor and can't give an authoritative opinion. You
    need to consult a real doctor or, preferably, a specialist, for
    that.

    However, it is my impression that kidney failure is unlikely to
    be a symptom of early stage prostate cancer.

    In the first place, I suspect that prostate cancer doesn't
    usually become a problem outside the prostate until it has grown
    pretty large in the prostate, which would make is very unlikely
    to be missed on a biopsy. I suspect the 25% miss rate, if it's
    accurate, mainly happens to men with very small tumors that have
    not spread. The miss rate must also, as Steve Jordan said, vary
    with the number of biopsy samples taken. It may be that the 25%
    rate applies for the old standard of six needle samples but not
    for biopsies with more needles (I had 12.)

    Secondly, prostate cancer usually metastasizes first to bones,
    especially the large bones and joints in the back, shoulders, and
    other areas. I _think_ (I'm not sure about this), that a
    metastasis to the kidney would not likely occur until after
    you've already experienced pain in other areas.

    Thirdly, when a significant, symptomatic metastasis outside the
    prostate occurs, the PSA usually gets pretty high. Most of the
    people I have known who have symptoms of any kind have had a PSA
    reading in the hundreds before they noticed any symptoms. I know
    one man who had a PSA of 500 and still didn't have any symptoms
    (though he was probably an exception.)

    So, while it's natural for you to be suspicious of prostate
    cancer when you've had a biopsy for it, I would be more concerned
    about some cause other than prostate cancer.

    As for when a second biopsy is recommended, in the cases where
    I've seen it done there was an increasing PSA. If for example a
    patient had a PSA of 6 and had a negative biopsy, then a year
    later his PSA was 8 or 10, or more, another biopsy might be
    recommended.

    The usual problem with biopsies is the opposite one from the one
    you are worried about. It's not that a significant cancer is
    missed, but that an insignificant cancer is found and the patient
    panics and demands treatment when, in fact, he doesn't (yet at
    least) need it.

    Good luck with the kidney problem. Be careful with it and find
    yourself a good specialist if you can who can help diagnose it
    and plan a treatment.

    Alan



  4. #4
    ron Guest

    Default Re: Prostate biopsy--false negative?

    On Aug 14, 8:31*pm, "Alan Meyer" <amey...@yahoo.com> wrote:
    > "Steven L." <sdlit...@earthlink.net> wrote in message
    >
    > news:[email protected]..
    >
    > >I have read that prostate biopsy involves about a 25% rate of
    > >false negatives. *That is, in 25% of negative biopsies, it turns
    > >out that the patient has prostate cancer after all.

    >
    > > What is current medical practice regarding when a second
    > > prostate biopsy is warranted, to make sure that the first
    > > biopsy was not a false negative?

    >
    > > I ask this because I had a prostate biopsy 14 months ago, which
    > > was negative for cancer. *But since that time, I've started
    > > experiencing kidney failure too, indicative of a rapidly
    > > worsening prostate situation. *That doesn't sound very "benign"
    > > to me.

    >
    > Steven,
    >
    > I'm not a doctor and can't give an authoritative opinion. *You
    > need to consult a real doctor or, preferably, a specialist, for
    > that.
    >
    > However, it is my impression that kidney failure is unlikely to
    > be a symptom of early stage prostate cancer.
    >
    > In the first place, I suspect that prostate cancer doesn't
    > usually become a problem outside the prostate until it has grown
    > pretty large in the prostate, which would make is very unlikely
    > to be missed on a biopsy. *I suspect the 25% miss rate, if it's
    > accurate, mainly happens to men with very small tumors that have
    > not spread. *The miss rate must also, as Steve Jordan said, vary
    > with the number of biopsy samples taken. *It may be that the 25%
    > rate applies for the old standard of six needle samples but not
    > for biopsies with more needles (I had 12.)
    >
    > Secondly, prostate cancer usually metastasizes first to bones,
    > especially the large bones and joints in the back, shoulders, and
    > other areas. *I _think_ (I'm not sure about this), that a
    > metastasis to the kidney would not likely occur until after
    > you've already experienced pain in other areas.
    >
    > Thirdly, when a significant, symptomatic metastasis outside the
    > prostate occurs, the PSA usually gets pretty high. *Most of the
    > people I have known who have symptoms of any kind have had a PSA
    > reading in the hundreds before they noticed any symptoms. *I know
    > one man who had a PSA of 500 and still didn't have any symptoms
    > (though he was probably an exception.)
    >
    > So, while it's natural for you to be suspicious of prostate
    > cancer when you've had a biopsy for it, I would be more concerned
    > about some cause other than prostate cancer.
    >
    > As for when a second biopsy is recommended, in the cases where
    > I've seen it done there was an increasing PSA. *If for example a
    > patient had a PSA of 6 and had a negative biopsy, then a year
    > later his PSA was 8 or 10, or more, another biopsy might be
    > recommended.
    >
    > The usual problem with biopsies is the opposite one from the one
    > you are worried about. *It's not that a significant cancer is
    > missed, but that an insignificant cancer is found and the patient
    > panics and demands treatment when, in fact, he doesn't (yet at
    > least) need it.
    >
    > Good luck with the kidney problem. *Be careful with it and find
    > yourself a good specialist if you can who can help diagnose it
    > and plan a treatment.
    >
    > * * Alan


    Approximately 70-75% of PCa tumors arise in the the peripheral zone of
    the prostate, the zone that is normally probed during biopsy. The
    remaining 25-30% of tumors originate in the central and transition
    zones, areas not routinely biopsied during a trans-rectal biopsy.
    Perhaps this is where the "25% miss rate" comes from...ron

  5. #5
    len Guest

    Default Re: Prostate biopsy--false negative?

    On Aug 14, 5:10 pm, "Steven L." <sdlit...@earthlink.net> wrote:
    > I have read that prostate biopsy involves about a 25% rate of false
    > negatives. That is, in 25% of negative biopsies, it turns out that the
    > patient has prostate cancer after all.
    >
    > What is current medical practice regarding when a second prostate biopsy
    > is warranted, to make sure that the first biopsy was not a false negative?
    >
    > I ask this because I had a prostate biopsy 14 months ago, which was
    > negative for cancer. But since that time, I've started experiencing
    > kidney failure too, indicative of a rapidly worsening prostate
    > situation. That doesn't sound very "benign" to me.
    >
    > --
    > Steven L.
    > Email: sdlit...@earthlinkNOSPAM.net
    > Remove the NOSPAM before replying to me.


    I've never heard any direct relation between prostate cancer and
    kidney failure.

    Kidney failure is possible in some cases for men who have difficulty
    urinating because of an enlarged prostate. Although that could happen
    because of prostate cancer, it would be unlikely unless the cancer
    were pretty far along. In that case, the PSA would most likely be
    very high, and a biopsy would be likely to find the cancer.

    But that is looking for a fairly exotic explanation, when BPH, just
    ordinary benign enlargement of the prostate, if it causes difficulty
    urinating and a man ignores it and lets it go long enough, is a more
    obvious explanation. My next door neighbor was such a man. He
    managed to live for many years on dialysis and died last year at about
    83.

    I don't know if that is the reason for your kidney problems. There
    are many other causes of kidney failure. You should make sure you
    discuss the matter thoroughly with your doctors and do what is
    necessary to resolve the problem. Ask them whether or not, in your
    case, it makes sense to pursue the possibility of prostate cancer any
    further at this point. If so, there may be some things they can look
    at to increase the likelihood of detection. As Ron notes, they might
    change where they probe. They may also check the so-called free PSA
    percentage, which, if it is low, may be more indicative of prostate
    cancer than BPH. But your primary concern at this point should be
    your kidney problems.


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