[blessthischick]

Flow cytometry results as indicator for progression

by blessthischick on Sun Apr 20, 2014 4:12 am

Hello all

Wondering if you can please help.

I recently had flow cytometry repeated after 7 months and I am not understanding a few things. I spoke with my haematologist by phone and he said there was a dilution of 3.8% cells used and 89% were abnormal 7 months ago and this time there was 2% dilution and 94% were abnormal. I am not understanding the dilution bit although apparently its to do with it wasn't the first lot of plasma cells that came out on aspirate?

In terms of risk to progress, I am sure I have read somewhere that greater than or equal to 95% abnormal plasma cells will put people at high risk for progression. However, my haematologist does not seem concerned and I am wondering if he is on the same planet as me?

Also I have had a conversation with my specialist nurse. There were 7% abnormal plasma cells in my aspirate and 10% on my trefine. She said they take the aspirate as diagnostic of SMM and I was under the impression that it was the trefine. She went onto say that by aspirate I am mgus and by trefine I am SMM. This has left me totally confused and I am wondering if anyone can shed some light on this? I was under the impression that diagnosis of SMM was based on trhe trefine?

I hope someone can help clarify...

Kay

[Multibilly]

Re: Flow cytometry results as indicator for progression

by Multibilly on Sun Apr 20, 2014 10:07 am

Hi Kay,

Maybe I can help you out here.

Parametric Flow Cytometry (PFC) looks for specific antigens (markers) on your plasma cells that are associated with multiple myeloma. Depending on the type of PFC being done, this could be looking for 4 or 8 different markers.

When the cells go through the PFC test, only those plasma cells with a given marker are counted. So, the results of the PFC are simply percentages of cells that have those individual markers. Healthy plasma cells don't usually have these markers.

Therefore, the PFC test results are NOT telling you that 95% of your plasma cells are abnormal. Rather 95% of those cells that have the specific multiple myeloma markers on them are "abnormal", which doesn't sound too unusual to me. After all, these are the cells that have the markers on them that signify that they are not typical to begin with.

When you talked to your nurse, she probably didn't use the word "abnormal". She probably said "there were 7% plasma cells in my aspirate and 10%....". Those percentages are simply a total count of ALL the plasma cells (healthy and otherwise) from your BMB. This is the percentage that is used in staging MGUS versus SMM, etc, NOT the PFC abnormal percentage counts.

In summary, your total plasma cell percentages of 7% and 10% are completely unrelated to the 95% abnormal cell percentage figure in the PFC.

BTW, I have no idea what "trefine" is.

[blessthischick]

Re: Flow cytometry results as indicator for progression

by blessthischick on Tue Apr 22, 2014 3:19 am

Hello again Multibilly

I am sorry I did put abnormal where I should not have, I realise that the bone marrow biopsy looks at the percentage of plasma cells and not only abnormal. I must have had a blonde moment. I am having a lot of these lately. I found my reading specs in my oven the other day lol thank goodness the oven wasn't on!

The trefine (actually it may be spelt trephine) is the sample of the bone they take after they have done the aspiration. Do you guys get that done as well? They use a needle much like an apple corer (although thankfully not as big!) and end up with a beautiful cylindrical pinky sample of bone which needs to be at least 2 cm long. I have been told by my consultant that this is the more accurate as opposed to the aspirate when looking for progression. Is any of that familiar to you?

I am still trying to get my head round the usefulness of flow cytometry, what is the point of it?

I am sure you asked me if I had other tests repeated, but these have disappeared from your post. I am wondering what they were? They have not repeated FISH, I was told there would not be any value in this. Is that true? Apparently t(14:16) is referred to as a primary abnormality that will be present from MGUS through smoldering myeloma and into multiple myeloma. Is is possible that this abnormality could change?

Again your help is much appreciated, Kay

[Multibilly]

Re: Flow cytometry results as indicator for progression

by Multibilly on Tue Apr 22, 2014 6:55 am

Hi Kay,

1. We do the same thing here with BMBs. We test both the aspirate (bone marrow) and the biopsy (bone + marrow cells). The biopsy apparently is also called a trephine biopsy, which is now a new word I can use in Scrabble

2. PFC is useful in that it can confirm if cells are indeed malignant and whether they are myeloma cells or not (they could be another kind of cancer, etc). By characterizing the antigen signatures (immunophenotype) and looking at those results over time, it can also help determine if the disease is evolving.

PFC is also exquisitely sensitive at detecting abnormal cells based on the markers it is set up to detect. So, when you are getting treated, it is a helpful test to see if you've actually completely knocked down the disease. When you hear about minimal residual disease (MRD) testing to see if you really have wiped out the myeloma or not, this is often the test they use to determine if you've gotten to zero MRD. So, PFC is very useful to see if you need further treatment or not during a particular treatment regime.

3. I guess if you have t(14:16), you already know you have a high risk factor for symptomatic multiple myeloma (it's not really completely characterized for MGUS for SMM), so I see the doctor's point about not doing any additional genetic testing.

4. It sounds like you already had the basic plasma cell percentage tests done as part of your most recent BMB, so not sure there really are an other tests that you would do against the BMB.