TNBC and MammaPrint

MountainMia

I see a lot of comments about Oncotype scores to predict potential for recurrence of BC. Oncotype doesn't work with HR-, and of course we TN gals are in that group. MammaPrint does supposedly work for TNBC.

I'll have my lumpectomy Thursday, IDC and DCIS, tumor originally measured at about 7mm. No decision on chemo yet.

Have most of you had MammaPrint testing done? What feedback do you have on it, for good or for bad? How were the results reported to you? Did you have to ask for the testing?

NancyHB

My understanding of both Oncotype and Mammaprint is they're used to drive treatment decisions based on tumor genomics. Part of that test result is the potential for recurrence (my first ER+ dx resulted in an Oncotype score of 42, most likely because my tumor was PR- and Luminal . That being said, triple negative is almost always treated with at least chemo, so I don't think many do the Mammaprint (and because it's meant to inform treatment I don't know if insurance would pay for it in the case of TN?) Any result is a generality of potential recurrence, not a guarantee of how/when it could recur.

What benefit would you get from the result? Would it help you decide on chemo, or would you want it specifically to measure potential recurrence

MountainMia

Thanks, Nancy. My MO does not automatically recommend chemo for TN but takes in size and lymph node involvement, and I expect other things, to his decision. I'm new to this and wondered in Mammaprint was one of the things included in that equation. Thanks again.

NancyHB

Standard of care for TN >5 mm is chemo because there are no other systemic options like Tamoxifen or AIs, and because TN tends to be aggressive (usually grade 3). On the plus side, TN usually respond well to chemo, so it’s really the first line of defense. With ER+ tumors there is more room for wiggle size-wise and node-status-wise, which is where the Oncotype and Mammaprint tests come in. The genomic testing offers insight into the aggressiveness (or not) of the particular tumor, which can better inform treatment decisions.

I did more reading on Mammaprint and it’s similar, but not the same as Oncotype, and offers interesting results. I wish I’d known more about it back when I had my recurrence.