MRI vs Biopsy - breaking news

[cesanon]

From pcri conference today. New article from New England Journal of Medicine.

MRIs are now proven superior to biopsies.

[Tall_Allen]

I don't agree. Here's a discussion of what it actually says - note my comments:

prostatecancerinfolink.net/...

[cesanon in reply to Tall_Allen]

Your analysis is a bit too nuanced for me.

Would you be kind enough to do a dumbed down version here.

I did pick up that an arm of the trial subjects didn't get the biopsy. Seems like you lose something without that.

But it seems like there should be enough information to inform a decision to do an MRI before doing a biopsy.

That seems pretty actionable to me.

[Tall_Allen in reply to cesanon]

No, there isn't enough information. For every diagnostic test, one needs TWO critical kinds of information: (1) how true is a positive result, and (2) how true is a negative result. Their study completely left out #2. In other words, an mpMRI with PIRADS 3-5 was more likely than a TRUS biopsy to find significant cancer at biopsy, but we have no idea how many significant cancers were missed when they were PIRADS 1 or 2. In other trials, an mpMRI failed to find significant cancer in about 15% of men.

The other questions I raised were these:

• Do men want to know when they have insignificant cancer? That is, should we get rid of the concept of active surveillance entirely?

• How do we justify the huge increase in cost (in the US) just to screen men? Isn't a test like PHI that only costs $125 a much better idea before a first biopsy?

• If we were to adopt mpMRI screening as standard of care, where would all the trained radiologists come from?

I hope this explanation was more understandable. Feel free to ask questions.

[cesanon in reply to Tall_Allen]

"Isn't a test like PHI that only costs $125 a much better idea before a first biopsy?"

What is a PHI test?

[ctarleton in reply to cesanon]

medscape.com/viewarticle/88...

[Tall_Allen]

Prostate Health Index, PHI, is a blood test that is pretty good at predicting whether a biopsy will be positive or negative. At a cutoff of 35, it has good accuracy: 65% of positive biopsies will have had a score over 35, and 65% of negative biopsies will have had a score under 35. And it's predictive accuracy is better for significant PC. It's a LOT more cost/effective at deciding whom to biopsy than giving an mpMRI to everyone.

[Raymonda100 in reply to Tall_Allen]

Is a 4 K test the same as a PHI test?

[Tall_Allen in reply to Raymonda100]

They are similar -- they both look for sub-types of PSA that only show up with prostate cancer. Their accuracy is the same. The difference is that 4Kscore costs about $400 and is not covered by medicare.

[Hidden]

MRI's are expensive and then I think the urologist would still want to do a biopsy to find out the gleason score. Doesn't an MRI just indicate that a tumor is present? A DRE can do that although it could miss a tumor that an MRI wouldn't. Can an MRI really tell anything more than that?

[Tall_Allen in reply to Hidden]

An mpMRI can indicate the degree of SUSPICION for a high grade cancer. It is very useful for the CONFIRMATION biopsy for men on active surveillance and for a SECOND biopsy when the first came up negative yet suspicion remains. DREs are pretty useless.

[Hidden in reply to Tall_Allen]

My PSA was a very innocuous and normal looking 2.7. Don't say DRE's are useless -- a DRE is what turned up enough suspicion to get me sent to a urologist. He did another DRE and then a biopsy. Gleason 8, 5 of 12 cores positive. My prostate cancer would still be growing, a year and a half later, absent that DRE. Too many people have stories that they were diagnosed only after they became symptomatic, meaning late in the game. I count my lucky stars that I had that DRE ... which I insisted on ... the GP kept putting it off to the next visit.

[adlerman in reply to Hidden]

I was saved by a "useless" DRE. I decided to use a VA clinic in Orlando instead of outside Doctors. Only problem at the time was High Blood pressure- an older Doctor doing the intake physical did a DRE- found a lump that turned out to be Gleason 8

with a PSA of 3.8- at the time under 4 was considered to be safe so without the DRE there's no telling what the cancer would have looked like when it finally caused problems.

[33Ford in reply to adlerman]

Yep, I ended up on the other side of that issue! My primary care dr quite doing DRE (I think this was in accordance with guidelines). And my PSA was 4.3, also conceded not that high at my age (73). A year later my PSA was 8.4, was sent to a urologist, DRE found lumps, biopsy ended up 9/10 in 11 or 12 samples! Then MRI, CT & Bone Scan. Ended up being stage IV 1ma. An earlier DRE sure would have been nice!

I had several MRIs and CT scans of my lower back and pelvis area earlier (like a month earlier) for a back and hip issue. No one noticed anything in these scans!!

[Ian2017]

An MRI didn't show cancer in my case (it was done on my lower back only and there was apparently 'insufficient contrast' to pick up the tumor which had metastatsized - no one was expecting a cancer diagnosis anyway). The cancer was revealed only in a subsequent bone scan. My PSA was low too (about .375) and has never been higher than about 6, so has never been a useful indicator of the cancer. I'd recommend a biopsy any day, for peace of mind if for no other reason.

[ewhite999]

My first biopsy was a false negative. An MRI a few days later showed cancer in prostate and beyond. This prompted a second biopsy which was positive. Needless to say, I’m a big believer in MRI’s. Biopsies are limited as they can’t take a sample from the far side of the prostate and that could be the only place cancer is present

[Tall_Allen in reply to ewhite999]

That is an ideal use of an mpMRI - to show what to biopsy when there is suspicion after a first negative biopsy. But that is a very different use from screening all men with elevated PSA with it.

[bigbassman]

My initial urologist booked me for a standard TRUS biopsy when my PSA rose from around 4 to around 10 over 8 months. His major concern in doing so, as he told me, was that my Free:Total PSA ratio had gone down to 0.12. That figure subsequently decreased to 0.08 by the time I started treatment. Recent DREs and a prostate ultrasound had all been remarkable. K4 and other PCa marker tests were inconclusive. After researching TRUS and becoming concerned about the level of discomfort and worse, the lack of accuracy vs MRI targeted types of biopsies, a concern confirmed by 2 PCa survivors I knew who had had 2 or more successive negative standard TRUS biopsies, I paid for an MRI, which, I'll admit, was driven more by my fear of the TRUS discomfort than by anything else. The MRI confirmed 2 large PCa tumours. In my case, a strandard TRUS would very likely have found my PCa, but I had no way of knowing that ahead of time. The MRI result really made my decision to go ahead ASAP with the TRUS biopsy, on the indication by the radiation oncologist that the MRI data would be used to target the TRUS biopsy. Results were very clearly Gleason 8 (4+4) in 9 of 10 cores.

[Tall_Allen in reply to bigbassman]

As you say, a single TRUS biopsy would most likely have found the same large tumors, and saved you some money. It's always impossible to know what would have been. In the study mentioned by the OP, they only took cores from suspicious areas and none from other areas.