Traditional vs. mapping biopsy: the pros and the cons


It has been widely argued that three-dimensional prostate mapping biopsies (3D-PMB) are necessary and more appropriate than traditional transrectal ultrasound (TRUS) biopsies in the assessment and staging of certain types of patient, most particularly those who are considering some form of focal therapy (e.g., cryotherapy or high-intensity focused ultrasound) to only one lobe of the prostate form treatment of unilateral prostate cancer.

Onik et al. have now published data comparing the results of 3D-PMB with those from traditional TRUS-based biopsy data in 180 patients who had initially been diagnosed with unilateral cancer on TRUS biopsy. These patients were all considering some form of conservative management, and were restaged with 3D-PMB prior to making final treatment decisions. The 3D-PMB was carried out transperineally using a brachytherapy grid under TRUS guidance. Biopsies were taken every 5 mm throughout the volume of the prostate, and labeling of the specimen coordinates allowed accurate reconstruction of the location and extent of each patient’s cancer.

The results of this analysis were as follows:

  • 3D-PMB was used to obtain a median of 50 cores (with a standard deviation of ± 20.61).
  • 110/180 patients (61.1 percent) were shown to be positive bilaterally by 3D-PMB.
  • 41/180 patients (22.7 patients) had their Gleason scores increased to ≥ 7.
  • 36/180 patients (20 percent) had negative results on 3D-PMB.
  • Complications of 3D-PMB were self-limited (in other words, they resolved over time without specific intervention).
  • 14/180 patients (7.7 percent) required short-term urinary drainage using an indwelling catheter.
  • 2/180 patients (1.1 percent) had blood in his urine (hematuria), and one of them required overnight bladder irrigation.

This study appears to confirm that transperineal 3D-PMB can be used with a high level of safety to accurately stage appropriately selected prostate cancer patients.

What is of particular interest to The “New” Prostate Cancer InfoLink is the high percentage of patients in this study — over 60 percent — who were initially assumed to have unilateral disease (based on the original TRUS-guided biopsy) but were in fact shown to have bilateral disease based on the 3D-PMB. This would suggest that the number of patients who needed interventional treatment at all (as opposed to some form of expectant management) and who were eligible for focal therapy is actually very small.

It should also be noted that although the adverse events associated with 3D-PMD in this study were relatively few, patients need to understand that 3D-PMD is not a benign procedure. Some men do have significant adverse events. These patients were all biopsied by a recognized and highly experienced cryotherapist. Whether the average urologist would be able to achieve similarly low levels of adverse events is not known.

Of course the critical question raised by a study like this is just who needs to undergo a mapping biopsy? We don’t have a good answer to that question at the present time.

6 Responses

  1. On August 11 at you posted the following:

    “Fota et al. report that preoperative needle biopsy data have limited correlation with the laterality of significant cancer and positive surgical margins in final pathology specimens after laparoscopic radical prostatectomy (LRP). In other words, even though the patient’s initial biopsy result suggests the presence of cancer in only the left or the right lobe of the prostate, it is very common to actually find cancer in both lobes at the time of surgery.”

    This and other studies continue to highlight the shortcomings of standard TRUS needle biopsies.

    In response to your poser, anyone with a life expectancy of over 15 years considering active surveillance or anyone considering treatment for “apparent low-risk disease” would do well to consider 3D mapping biopsy. It is the best technique currently available to determine the nature and extent of prostate cancer, and Dr. Onik uses it as a basis for follow-on focal treatment if appropriate.

    As with all treatments and procedures, you get the best results from doctors who are recognized and highly experienced. The “average urologist” doesn’t do this procedure. I developed a urinary infection after a TRUS biopsy, I didn’t after a transperineal 3D mapping biopsy.

  2. Which leads us to three related questions: (1) Is the standard, TRUS-guided biopsy a waste of time in an environment (e.g., the USA today) in which the vast majority of men are diagnosed with relatively low risk disease? (2) Can we afford to give a 3D mapping biopsy to everyone who needs a biopsy? (3) If the standard of care was the 3D mapping biopsy, might more men who perhaps don’t really need a biopsy think harder before they agreed to this?

  3. The sitemaster asked:

    Which leads us to three related questions:

    (1) Is the standard, TRUS-guided biopsy a waste of time in an environment (e.g., the USA today) in which the vast majority of men are diagnosed with relatively low risk disease?

    Since 3D-PMD is hardly in the cards to become SOP, TRUS-guided biopsy will continue to be the SOP. What Onik reports is that those with what is considered unilateral disease have to consider the multifocal and heterogeneous nature of PCa which complicates the issue for those that claim the low risk of the currently diagnosed disease. This also, in part, explains the high failure rate of current PCa treatments.

    (2) Can we afford to give a 3D mapping biopsy to everyone who needs a biopsy?

    Never in a million years. As it is 3D-PMD is hardly ever done. The way care is going these days, and with the current controversy about the value of testing with PSA, we will be lucky not to see a reversal in the mortality rate.

    (3) If the standard of care was the 3D mapping biopsy, might more men who perhaps don’t really need a biopsy think harder before they agreed to this?

    Be assured that this would be an overkill situation for the great majority. Economically the system would not be sustainable. Patients are driven to biopsy and treatments because most lack of them basic prostate cancer education. As long as this is the case, men will remain in the twilight zone …

  4. (1) Isn’t what we are really talking about “APPARENT low-risk disease.”? Based on the information that you continue to post, 25 to 35% of men are under-staged, about 10% of men are over-staged by TRUS biopsy with some of showing no prostate cancer at all upon mapping biopsy.

    (2) Can we afford it? I certainly can’t say what Medicare, etc., can bear. Mine was done as an outpatient procedure for ~$3K. Really knowing was worth that to me — the insurance ended up paying most of it.

    (3) Good point. It’s easier to talk yourself out of prostate cancer if you haven’t had a biopsy. This might keep some men away who should be kept away; however, others?

    How many stories have we seen posted on the social network where the TRUS biopsy came back low to moderate risk disease and surgery showed something much worse? Too many. You have to wonder if some shouldn’t have gone directly to ADT. Scans don’t seem to pick up metastasized prostate cancer very well.

    Seems to me that knowing the nature and extent of prostate cancer before monitoring or treating it would be a good thing. I just wish it could be done with imaging instead of all those needles.

  5. I’ve had two “top in the country” robot surgeons say that the saturation biopsy could make nerve-sparing surgery more troublesome. One said that the effect of biopsy can be hit or miss. Sometimes he sees no impact and other times, even a traditional six-core can leave the prostate as “if a hand grenade had been set off.” He then went on to say that 50 cores would then increase this risk. I’ve been on expectant management for about a year and am considering the two types of follow-up biopsy.

  6. It took two 12-core biopsies to find the one core of cancer they found. The cost was about $1,900 each, for a total of $3,800 out of pocket to me. The cost for the mapping biopsy was about the same but found tumors in the same area that was found with the two 12-core biopsies. Other than having a catheter for about 2.5 days (which I removed myself) I found I had much more information and confidence in the extent of my disease. There was actually less pain as you don’t feel the needle going off and it did not take that long for the anesthesia to wear off. I have to think if this became the standard of care, it would become cheaper.

    Robert

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