How aggressive is IDC with a ki-67 of 93%

Based on my understanding, Ki-67 represents the percentage of cells that are dividing meaning the speed at which the cancer is growing. Lower numbers are better. 1% would mean only 1% of the cancer cells are dividing. 100% would mean all cancer cells are dividing. 93% is aggressive. My original breast cancer had a Ki-67 in the teens so moderate. My recurrent breast cancer is Ki-67 50% so it’s considered aggressive this time. I did surgery, radiation and have been on Kisqali and Letrozole for 4 years now and doing well. My neuroendocrine lung cancer (NETs) is Ki-67 2% so very very slow growing. Based on symptoms and old scans I’ve likely had lung NETs for at least 30 years and it still hasn’t spread outside my lungs. Higher Ki-67 is likely to spread faster.

Sorry to hear about your breast cancer. Good that you are starting treatment soon to squash your cancer. You’re going to see better days. You’ll get through this. Prayers for you.

Thanks. Just had PET and lymph node biopsy at Mayo in PHX. 🙏🏻

I never got tested for ki67 so I don’t know a thing about it. I just want to wish you all the best. You’ll get through this hump and feel better soon. 🤗

The ki is on pathology report when they looked at tumor cells. Usually pretty small print embedded in the report towards the end of dictation.

When I was first diagnosed with Triple Neg. Breast Cancer.... the only other test result from the biopsy were the KI67 , which was very low with me. I focused on that result for at least a few weeks before I accepted what matters to me is that I'm taking care of getting rid of this. In my case it was a small, positive for cancer, tumor, surgery, and chemo.... 5 months long.
KI67 is just a marker, or indicator, for something we all know about cancer... time is not our friend when it comes to treatment... Whether you have a faster growing cancer or not.... take care of business.

When I first learned I had invasive breast cancer, I assumed the treatment would consist of some combination of surgery, chemotherapy and/or radiation. I knew that cancers had stages but was unaware of "grades" as well. Reading the biopsy report and seeing mention of Grade 3 and a Ki-67 of 50% rudely introduced me to the biological aspects of the cancer cells themselves. With a grade 3 and Ki-67 of 50%, I considered my cancer, though staged as !C, to be aggressive. A relatively high Oncotype DX score added to that conclusion and chemotherapy was added.

My oncologist, however, does not really get into any detail in answering my questions about Ki-67, e.g., what exactly is it? If is a gene? A protein? I'm not how widely the test is even used when doing biopsies. I've also read that different labs can reach different measurements. In my own case, my initial biopsy showed a 50% level of Ki-67 but the biopsy done during my actual double mastectomy came back with 30% which is still high, though lower.

Based on my diagnosis, I think my oncologist may be recommending not only an AI but also a CDK-inhibitor. I think CDK inhibitors may initially have been recommended for metastatic breast cancer, but now seem to have broadened in their use to include higher Ki-67 levels.

I've found articles about Ki-67 but don't get into their details. I know that the my 3 biological markers (grade, Ki-67, and Oncotype) suggest my cancer cells are aggressive.

I should mention that when you get the Oncotype DX results, you are given a basic number but no breakdown of the actual genes which are tested. I had a genetic test done prior to my breast cancer diagnosis and tested negative for the BRCA genes and any other genes associated with breast cancer. I'm curious what those other genes could be that were picked up by the Oncotype DX test.

I was told that the genes tested in the Oncotype are not related to your genes but the tumor genes. Ki67 is a protein produced by the gene MKI67 that is included in the Oncotype’s tests . And they also explained that KI67 is determined by the professional that examines the tumor so it’s subjective.

Angiemal: Thanks for that additional info!