Ki-67

it's the amount of cells in percentage that were dividing at the moment when the sample was taken.

My ki67 on my biopsy was under 1, at surgical path under 5. But oncotype was 13, high end of the “low” range and higher than some people on this forum read as having grade 2. Makes no sense

Veeder, as Gudrun described above, ki67 is expressed as the percentage of cells in the sample that are dividing (getting ready to grow). The higher the percentage, the more aggressive the cancer is expected to be. Anything over 20% is considered “high risk”. Because the test is visually determined it’s not necessarily considered the best predictor of aggressiveness, and some no longer test for it. Do you have your ki67 %?

Ki67 correlates in some ways to grade, which is how the cells look - how well differentiated the cells are and how fast they’re growing. When I was first diagnosed my ki67 was 40% (my ER was only 50% positive) and my grade was 2 (and my Oncotype was 42); second diagnosis my ki67 was 50% (I was TN that time) and my grade was 3, so you can have a mid-grade cancer with a high ki67. My MO explained that some of that may have to do with ER and PR receptors (negative is more aggressive than positive).

Chronicpain, part of the reason we see different numbers from biopsy to Oncotype is that biopsy is often a small sample of the tumor. Breast cancer tumors tend to be heterogenous, so when Oncotype testing occurs they’re grinding up and testing the whole tumor rather than just a tiny sample. It’s far more comprehensive of a test and provides more detailed information than the biopsy. It’s not necessarily dissimilar (we can trust our biopsies to give us grade and receptor status), just more detailed.

All of these tests and numbers get confusing but they do work together to create a detailed look at our particular cancer, which really helps hone and drive a personalized treatment plan.

Meow, my first biopsy didn’t either - my MO didn’t test for it at the time. I had to ask for it and at first they refused, then did it when my Oncotype score came back so high. By the time I was dx’d again they were testing all biopsy samples. I feel they believe it’s one more piece of the puzzle