What type of test should I request

trinigirl50

Hi All

My tumour is set to be dumped next March after 5 years according to my BS (ex).

I have extremely high probability of recurrence and want to do a diagnostic test on the tumour should new therapies for prevention become available in the future for high risk persons like myself. Alhough I have googled myself into a tizzy, I cant find any definitive answer on what is the most useful/comprehensive test I should have done. I have ILC pr- so I suppose Ecaderin loss should be included?

The only test that was ever offered to me was the standard Grade, Er Pr and Her2 test.

Any suggestions?

I posted here because this seems to be a thread where posters are as current as possible with the breast cancer world.

thanks in advance.

LoriCA

trinigirl50 it sounds like you want to have NextGen genome sequencing done, which is done by labs such as Foundation One and Caris. That test is to find acquired mutations in the cancer (as opposed to inherited mutations found with genetic testing) that could ideally be targeted with precision treatments. Honestly though, I don't think it makes sense to have it done on an old tumor sample. From your profile it looks like you were diagnosed at an early stage and have completed treatment? If you were to have a recurrence, you would need to have a new biopsy and it would make sense to request genome sequencing at that time. At my last biopsy we took extra samples specifically for this kind of testing. The test is expensive (mine with F1 was $6800), not all insurance companies cover it, and only a small number of people are finding actionable mutations because it's still in it's infancy. It would make more sense to have that kind of testing done if/when the cancer returns for two reasons - the cancer may not be exactly the same as it was the first time (even things like ER, HER2 status can change, which is why you would need a new biopsy), and there will likely be more knowledge about precision oncology, more biomarkers they know to test for, and hopefully more actionable mutations in the future.

FWIW the only thing actionable on my F1 test was my HER2 status, which we already knew, so the $6800 was a complete waste for me (my insurance did agree to cover after some fighting about it).

trinigirl50

Thank you LoriCA

I guess I was hoping they might come up with new therapies for certain mutations before my disease progressed (which I hope never happens). The thought behind getting the test was so that I could take advantage of any new therapies as a preventative measure as opposed to curative/or delaying measures. I know they are doing a clinical trial for ecadherin loss (or hope to do one soon) so I figured if I tested my tumour before it was destroyed and found specific mutations, I could use any new therapy as a preventative (like the AIs).

But I take your point. It is too early in the process as yet, and any mutations found will probably not be actionable. Maybe I will ask the lab to hold onto my tumour for a couple more years.

Thank you for your sound advice.

FarAwayToo

What Lori said above.

I asked my oncologist this question and she said that the value of testing the original tumor is pretty small. If one recurs, the ideal is to get recurrent tumor biopsied, as it most likely will have some new mutations. She said if getting to the metastatic tumor is an issue, liquid biopsy (testing blood) is sometimes an option, although not as accurate.

She told me straight up "if you recur, I will not go by your original tumor pathology, I will want to know the biology of your cancer at that point".

ShetlandPony

Trini, all I can think of is whether additional testing could inform the decision of five years versus ten years of letrozole.

Also you might want to see if any ILC researchers would be interested in the tissue. Maybe try lobularbreastcancer.org

santabarbarian

You might consider asking that they run a few specific tests, that would be cheaper and possibly practical. PDL1, TILs, AR receptor status, etc These are all tests that might inform maintenance type programs or prevention programs. TILs is predictive in a positive way. PDL1 drugs exist now. AR drugs exist now.

Sometimes the recurrence is hard to biopsy and in that case it could be good to have more data.

trinigirl50

Thank you Shetland Pony. I am pretty sure they will tell me 10 years of Letrozole based on my pathology, although I would love to stop taking it.

I understand that if I progress I need to re biopsy but I was talking about preventative therapy so Santabarbarians advice is spot on and I am going to discuss that with my oncologist. If that peters out, then I will see if I can donate my tumour to Lobular researchers.