Using MRI-guided biopsies to diagnose prostate cancer with high accuracy


Many prostate cancer patients — and particularly those who don’t like the idea of prostate biopsies — think that if one uses MRI-guided biopsies alone one might only need to have one or two biopsy cores taken to accurately diagnose prostate cancer.

Alas, this is a misguided perception, and an interesting study (by Lu et al.), to be presented at this year’s annual meeting of the American Urological Association, shows us just how misguided.

Between 2012 and 2016, Lu et al. administered MRI/TRUS fusion biopsies to > 600 patients at their institution in Connecticut. All the patients were given both a systematic fusion biopsy and a series of targeted biopsies. All the MRI scans were evaluated by experienced genitourinary radiologists (using both the Likert and the PI-RADS classification systems), and all the biopsies were carried out by one or other of two experienced urologists who were highly familiar with the use of MRI/TRUS fusion-guided biopsy processes.

In addition, with regard to the biopsies of targetable “regions of interest” (ROIs) visible as a consequence of the MRI scans, each of the ROIs visible in the prostates of the patients were sequentially biopsied multiple times to see if this made a difference to the chances of diagnosing either any prostate cancer at all or prostate cancer that was of greater clinical significance.

Here is what Lu et al. report are their core findings:

  • 628 patients were given MRI/TRUS fusion-guided biopsies (out of 744 patiensts who were initially given MRI scans).
    • 465 (62.5 percent) were suspected of having prostate cancer.
    • 163 (37.5 percent) were already known to have prostate cancer.
  • 1,233 ROIs were identifiable in the prostates of the 628 patients.
  • Each ROI was biopsied with an average (median) of five targeted cores
  • 581/1,233 ROIs (47.1 percent) were positive for prostate cancer of any Gleason score (≥ 3 + 3 = 6) in 380/628 patients (60.5 percent).
  • Cancer detection rates overall increased significantly with an increasing number of biopsy cores (see Table below)

Specifically,

  • For prostate cancer of any Gleason score (≥ 3 + 3 = 6),
    • Taking just one targeted biopsy core from an ROI identified only 69 percent of all cancers
    • Taking five cores identified 99 percent of all cancers
    • Taking additional cores beyond the first five had no significance.
  • For any clinically significant prostate cancer with a Gleason score of > 3 + 4 = 7,
    • Taking just one targeted biopsy core from an ROI identified only 54 percent of the relevant types of cancers
    • Taking  five cores identified 96 percent of the relevant types of cancers
  • For PI-RADS 4 lesions, additional sampling up to 6 cores significantly improved detection of  prostate cancer with a Gleason grade of ≥ 3 + 4 = 7 detection
  • For PI-RADS 5 lesions, sampling beyond four cores did not improve detection of  prostate cancer with a Gleason grade of ≥ 3 + 4 = 7

In other words, it was essential to take more than one core (and often as many as five or more cores) from each ROI to accurately diagnose the patient on the basis of the targetable lesions identifiable by MRI.

This study, carried out by a group of clinicians who were already experienced in the use of MRI scanning of the prostate and its application to targeted biopsying of the prostate, should make it very evident that — even with high quality MRI scanning — it is simply not possible to accurately diagnose prostate cancer on the basis of a single biopsy core from each targetable lesion.

Prostate cancer simply isn’t that cooperative.

7 Responses

  1. I am a prostate cancer survivor and I had 12 core samples taken in my biopsy procedure. I was lucky that my urologist was very experienced in performing the current biopsy. The invasiveness of this practice causes concerns since the needle core samples involve the needles piercing the rectum. Having newer procedures is a great thing. There is also another recent post of a blood test called isoPSA to diagnose prostate cancer. Again if approved and is found to be effective could be better for the patient. With the needle core samples there is a chance of the urologist missing the target which could create a false negative? Glad to see research is progressing to find better diagnostics for this disease. Might be that some men decide not to proceed when they get detailed information of how the needle core samples are taken but this is a dangerous way to deal with prostate cancer. Just another observation. I have a friend who chose to proceed with HIFU as a remedy for his prostate cancer and there was a point made that there is no biopsy performed with needle core samples. However, this person had a problem later as a known side effect of a collapsed urethra. He ended up going to the emergency room and also had to have a stent placed in his urethra as a needed remedy for an extremely painful side affect.

  2. Dear William:

    I have no idea who treated your friend for prostate cancer with HIFU without first giving him a biopsy to confirm that he actually had prostate cancer — but most physicians would consider that to be unethical and bad medical practice.

  3. OK. Thanks for the reply. … It is possible I had the wrong understanding about the biopsy at where the HIFU procedure was done as info from this friend of mine? I was focusing on some other way to get a prognosis than from the 12-needle samples for other men when they receive positive PSA results. My results out of 12 needle samples I had 3 of the 12 as Gleason 3 + 3 and 1 more as Gleason 3 + 4. Hoping researchers will develop a less invasive procedure for confirming a diagnosis of prostate cancer. I did understand what was explained … in the information I read.

  4. Sitemaster, sorry for the delay in this new reply. I have about 3 to 4 months of intense research before I decided on what treatment I was going to select. I think the person who is a friend of mine actually already had received a biopsy using the current method of detecting prostate cancer? I do not remember the exact conversation now that I try remember the details. The friend actually had to go to one of the Caribbean areas or country, not sure of actual place, because FDA had not approved the procedure in the US when this person had the procedure done on him. When I was looking at HIFU it had been approved in the US (maybe before 2016) but it was I guess never ok’d for actually treating the prostate for cancer….just the term I read regarding HIFU procedure. May have been a Site-master, like yourself think it was something like an ablation of the gland??

    The person I was talking about is the one who had a collapsed urethra some time after he completed the treatment and had to go to the emergency room. He was told about this as a side effect. He was back here in the US and had to have a stent placed from a surgeon or urologist at a local hospital near his residence.

    I just read last week from Med-Ed about the new test for PSA is IsoPSA, which was not being used when I had my biopsy back in January 2017. Not sure if FDA has approved this as of March or April 2018? I was mentioning the information I thought I had about the HIFU procedure, as there would not be any needle puncture samples done? I was really surprised when I had heard some men would actually not get a biopsy because of the invasiveness. I really think it was a very small group but that being true these guys were taking a big chance of dying from prostate cancer. What I read about the IsoPSA procedure, that it would eliminate having to go with the current biopsy procedure and it was also more accurate with the results. I also had read that this new procedure made some urology doctors not too happy because they would not be doing the blood testing and thus they would not be billing the patient for this procedure? This may not be accurate as well?

    Thanks for your reply and comments and hope if this new way of a diagnosis of actual prostate cancer is going to be approved it will be much better for the patients. One other point, I have another friend who I worked with for about 15 to 20 years and he has had several of the current methods of biopsies because some were “false positives” he told me he was really getting tired of going through some of the false positives for about the last 5 to 8 years.

  5. Dear William:

    In November last year Genomic Health and Cleveland Diagnostics agreed to work together to commercialize the so-called IsoPSATM developed at the Cleveland Clinic, but this technology is not yet commercially available and — as far as I am aware — no one is suggesting that the IsoPSA technology will be able to actually diagnose prostate cancer. What they are saying is that they hope it will have value in helping to determine who needs and who does not need a prostate biopsy, which is a very different issue and which is going to come with all sorts of legal and ethical questions.

    While lots of men would certainly benefit from not having to have prostate biopsies because they do not actually have prostate cancer, you also need to consider the fact that there is a significant but relatively small number of men who have relatively low PSA levels and no immediately evident symptoms of disease who do actually get diagnosed with aggressive forms of prostate cancer when they are biopsied. Any test that suggests that such a man doesn’t need a prostate biopsy and who subsequently is found to have aggressive disease will present problems for the test manufacturer and for the physician who fails to biopsy the patient based on such a test.

    I think we all need to be cautious about some of the new tests that are in development until we get data from much larger trials and can have much more insight into exactly what such tests do and don’t tell us.

    I am going to repeat what I told you previously, which is that the only currently approved method for diagnosis of prostate cancer is based on a positive biopsy specimen. Many other tests can help to determine whether a biopsy is really necessary in a particular patient, but none of those tests can give an accurate positive determination of the presence of prostate cancer at this time.

  6. OK. Thanks for this info as I had read some similar info several months ago.

    I did not realize what you explained is not what I got from what I read before.

    The good thing is researchers are continually working on better ways of dealing with prostate cancer treatments. Being able to get info such as what you as a site master publish is a great thing. Most of the physicians, since I had three consultations, do not seem to really give their opinions of treatments except if they do surgeries, radiation, or hormone procedures as their field of expertise.

  7. Thanks for your explanation. It seems to me you really have to do intense research to decide how to deal with this disease. The current procedure for biopsy as I read is best or the only offering at this time. There has been mention of the urologist missing a target sample which could leave a cancerous lesion to be a false negative. Point here is that the urologist performing the biopsy has to be experienced & very skilled. I was very fortunate to have a very skilled urologist as pathology examined the four cores out of 12 and when I had decided to go with the radical prostatectomy the entire gland and some surrounding tissues removed all of the cancer was contained in the capsule. Last three PSA tests I had after surgery showed levels of 0.01.

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