May 31, 2020 08:26PM - edited May 31, 2020 08:36PM by ShetlandPony
Hi, KMom. I will share some thoughts that you may wish to discuss with your oncologist. These are the musings of an educated and well-read ILC patient, but one who has no medical degree.
Your Oncotype test was done on the original biopsy of the tumor. You said, “And that biology hasn't changed just because more nodes. Right?“ You also said, “ I did 6 mos letrozole which appears to have shrunk the tumor but didn't clear the nodes.“ My thought about this is that maybe the cancer that was/is in the nodes has a somewhat different biology from the biopsy sample. That it developed mutations that made this sort of subset one with more of a tendency to spread and more of a tendency to resist letrozole. In other words, if they were to analyze the original tumor biopsy vs. the cancer in the nodes, it would be different, with the node cancer having a more aggressive profile that could have sent cells to distant sites. And so maybe chemo should be considered.
The other thing is that I am starting to think that because Oncotype was validated with mostly IDC (and postmenopausal women), and because the studies of LobSig showing that Oncotype and PAM50 (Mammaprint) may not be the best tests for ILC, the clinical characteristics of the cancer should be given more weight when it is ILC. So, with all those nodes, lvi, and tumor size, once again, chemo should be considered even though the Oncotype score is low. Even more so if you are premenopausal.
Here is a link to a paper about LobSig. This test is not available for use yet.
(By the way, in case you are wondering, I was premenopausal and my Oncotype was 16.)