Does Ki67 Score Outweigh Oncotype Score in Breast Cancer?

They are 2 different tests really. The Ki-67 is the doubling rate of the cancer cells while the Oncotype looks at particular mutated genes, ATM, BRCA 1, Rad 51 etc…. With a KI-67 I’m wondering if they recommended chemo even if you have a low Oncotype? I had a 16 but Ki67 was a 2 so chemo wouldn’t have targeted my cancer cells

Thank you for answering …I am taking Anestrozole an aromatase inhibitor for 5 years and possibly longer depending on how I do. I had DCIS 20 years ago so the high KI67 was a huge concern for me especially with this being my second go round

Hopefully the AI’s will do the job and you have no issues. I don’t even know I’m on Tamoxifen. I will switch to AI if I ever hit menopause (I’m 51). Good luck. At least it was caught early!

Judy I had similar results High Ki67 and borderline Oncotype score. I was recommended chemo and also an Anestrozole. I chose Tamoxifen first for 2 years and then will switch to anestrozole. When I switch I will need to get treatment to lessen bone loss.

I had ki67 of 30%, my oncotype score a 5 so no chemo. I did call a scientist at the oncotype facility to ask why such a low score and ki67 of 30%. They said all of the proliferation markers in my tumor were very low and that the pathology report uses a different metric. So I contacted the pathologist at the hospital I worked at and he said the ki67 is subjective which is why a lot of states don't use it and that the oncotype process has been tested for well over 20 years and to put stock in that test. He looked at my tumor and felt it was really between 10 to 20% and not 30%. Hope this helps. I also had 1 positive lymphnode.

Oncotype can determine luminal A or B also which determines the aggressiveness type genome. I’m guessing from my reading. I have ki 67 over 70 and luminal B so….

This is such an understandable question when test results seem to tell different stories. Both Ki67 and Oncotype DX provide valuable but different information - Ki67 measures how quickly cells are dividing, while Oncotype DX looks at multiple genes to assess recurrence risk and chemotherapy benefit. These tests work together rather than one automatically overriding the other, and oncologists consider the complete picture including tumor size, grade, and other factors when making treatment recommendations. Many others in this community have navigated similar questions about conflicting or confusing test results, so hopefully others will share their experiences and insights.