Question for hemepaths

[pathstudent]

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My best friend was just diagnosed with aml m3 acute promelocytic leukemia. They did morphology, flow , fish and cytogenetics on his blood. They scheduled him for a bone marrow but I don't see the point of it his t(15;17) came back positive on 98% of the cells. What can a marrow add? I dint get it. He is being seen at an elite top 20 academic hospital. So I assume they k is what they are doing. But I don't know why he would need a bone marrow biopsy. Can someone help out.

 

[Parts Unknown]

At my fellowship training institution a bone marrow biopsy was required for all patients being put on a protocol (which was most of them).

Even without a protocol, it is always nice to have a "baseline" marrow available for comparison against the day 14 marrow. If your friend is young there usually isn't a compelling reason to cut corners.

 

[2121115]

Virtually all leukemia treatment protocols require a bone marrow biopsy to place the patient on the appropriate treatment path. To be honest, I am not sure how they derive these algorithms.

 

[Freak]

Dumb medstudent question, but I thought APL/M3 was treated with ATRA with great success.

 

[Parts Unknown]

Dumb medstudent question, but I thought APL/M3 was treated with ATRA with great success.

Indeed, APL has a much better prognosis than other forms of AML due to ATRA + chemo. Unfortunately, there is always a minority of patients with stubborn leukemic clones that do not respond well to conventional therapy.

 

[Giemsa]

At my reference centre, they repeat flow, genetics etc. on the marrow even if they've done it hours earlier on an initial peripheral blood sample.

I asked about this (since it seems redundant) and was told that it was because the WHO categorization is based on the findings in the marrow, not the peripheral blood.

Having said that, I've never seen a case where the phenotype / genotype in the peripheral blood was substantially different than that in the marrow.

Has anybody else?

 

[pathstudent]

At my reference centre, they repeat flow, genetics etc. on the marrow even if they've done it hours earlier on an initial peripheral blood sample.

I asked about this (since it seems redundant) and was told that it was because the WHO categorization is based on the findings in the marrow, not the peripheral blood.

I thought AML could be diagnosed based on 20% blasts in PB, maybe things have changed the last few years.

I guess if they want to see how the marrow is responding durring induction, then it makes sense.

 

[Giemsa]

I thought AML could be diagnosed based on 20% blasts in PB, maybe things have changed the last few years.

No, that's right.

My reference center supposes (theoretically) that there could be subtle molecular or immunohistochemical differences in the blasts that end up in the peripheral blood and those in the bone marrow, and that categorization/ prognostication should be performed on the bone marrow blasts.

I've never seen a case where the flow/molecular/cytogenetic results differed substantially enough between blood and marrow to change the diagnosis.

 

[2121115]

I have seen several cases where unexpected markers were picked up on the blasts in the marrow which were not on the PB blasts - CD7 mostly. In those cases we never would have known to look for CD7 on the residual blasts in later marrows to see if they were persistent disease. It didn't change the diagnosis, but it was helpful nonetheless.

 

[yaah]

At my reference centre, they repeat flow, genetics etc. on the marrow even if they've done it hours earlier on an initial peripheral blood sample.

I asked about this (since it seems redundant) and was told that it was because the WHO categorization is based on the findings in the marrow, not the peripheral blood.

Having said that, I've never seen a case where the phenotype / genotype in the peripheral blood was substantially different than that in the marrow.

Has anybody else?

While that may be true, to me it sounds more like a justification for doing more billable tests. You don't need to do it on both. Sometimes they get done on both if there are questionable blasts on the PB. But if it's someone who has a suspicious peripheral blood and is likely to require a bone marrow anyway, there is very little point to do flow on the PB. The reason for sending cytogenetics is to get it started before the marrow is done, and there is no real reason to repeat that on the marrow.

You do not need flow to make a diagnosis of AML. Cytogenetics is required for classification but not flow. Some argue that you should do it to see if there is an aberrancy you can follow but others would argue it still isn't necessary.

 

[pathstudent]

Yeah and in my friends case they have (15;17) they can follow with fish and maybe pcr which is a million times better than flow for residual disease. And besides even if flow does detect 1% blast with cd7 are there protocols for therapy.

Flow has to be the most overutilized test. In my experience all it adds to most lymphoma cases is a two thousand dollar bill. You don't need flow to dx dlbcl follicular burkitt mantle Hodgkin etc. It is useful in minute biopsies or fna specimens to establish kappa lambda restriction but that is about it. The worst is where it is ordered and run on metastatc cancer cases simply because the surgeon writes history of lung cancer rule out met vs lymphoma

 

[cjw0918]

I'm sorry to hear about your friend. As someone who's had a bone marrow bx (NOT fun!) I'll tell you what I recommend. Tell your friend to ask for sedation-I got Versed (sp?) and Ativan but it didn't work that great b/c I don't think they gave it enough time to take effect. So make sure they give it a couple of minutes before they do the procedure. The only good thing about the procedure is that it's fast. The aspiration will make you see stars, but it's only a few seconds. Best of luck to your friend.

 

[pathstudent]

I'm sorry to hear about your friend. As someone who's had a bone marrow bx (NOT fun!) I'll tell you what I recommend. Tell your friend to ask for sedation-I got Versed (sp?) and Ativan but it didn't work that great b/c I don't think they gave it enough time to take effect. So make sure they give it a couple of minutes before they do the procedure. The only good thing about the procedure is that it's fast. The aspiration will make you see stars, but it's only a few seconds. Best of luck to your friend.

Thanks. It was done today under sedation.

Good to know. I can't believe they were always done under local. You hear about how medicine was done 30 years ago and it seems so primitive and cruel. It makes you wonder what things will be like 30 years from now and how they will view us.

 

[lipomas]

Thanks. It was done today under sedation.

Good to know. I can't believe they were always done under local. You hear about how medicine was done 30 years ago and it seems so primitive and cruel. It makes you wonder what things will be like 30 years from now and how they will view us.

Reminds me of that star trek movie (#4?) where they go back in time and McCoy encounters an old frail woman on a stretcher and asks her what's wrong with her. And she says "Dialysis." He proceeds to then cure her with a pill and calls it the dark ages. Who knows where medicine will be in the future. All we know is that there will be two things intimately involved

1) Robots
2) Lawyers to keep track of all the patents on tests and equipment.