Help me make sense of this?

shelleym1

How can I have a low Oncotype, a mitotic score of 1 (Grade2) but yet have a 26% ki67 proliferation rate? That's high! It just doesn't make sense to me. I don't see my onc for a few weeks and I will ask her then. But I was curious if any of you had this happen as well?

123JustMe

What is Ki-67?

An antigen is a protein that sits on the surface of a cell and stimulates the production of an antibody. Ki-67 is an antibody marker to a tumor antigen that can be found in breast cancer cells.

If your tumor is tested for Ki-67, your pathology report will show a Ki-67 score. High scores—greater than 20%—mean that the cancer cells are growing and dividing at a rapid pace.

Higher-grade tumors typically have a higher Ki-67 score. However, there is no conclusive evidence that Ki-67 is associated with survival. Some studies have found that it is; others have found that it is not.

Some studies have suggested that there are certain estrogen receptor (ER)-positive tumors with a high Ki-67 score that may not respond as well to tamoxifen or an aromatase inhibitor. However, they do respond well to chemotherapy.

You should not worry if your pathology report does not include information about your tumor’s Ki-67 level. Some labs do the test; others do not.

If you had an Oncotype DX test done on your tumor, Ki-67 is one of the 21 genes the test used to predict your breast cancer recurrence risk.

123JustMe

This is from Dr. Susan Love. Seems like there is nothing "standard" when it comes to breast cancer.

Stacy7

I also would love a response to this thread other than susan love or google article because i barely understand it.. I need to hear from women that have had input from their onc on this topic

shelleym1

Interestingly enough I was not advised to have chemo due to low oncotype score. Just surprising that oncotype would turn out low with a high ki67. I've read plenty on google about what Ki67 is and all. But just trying to make sense of it all.

tshire

Doesn't make much sense to me either- I am grade 1, mitotic index 1, with a higher ki67 and Oncotype than you have (see stats). I have a very high ER/PR+ rate too. Mammaprint came back high risk Luminal B so I guess I'm doing chemo.

I thought this study about long term prognosis with Luminal B type BC was interesting. They looked at almost 10,000 European women treated in the past 10-20 years and reclassified them based on the new definition on Luminal B (ER/PR+, ki67>20). Highly recommend reading: http://www.breast-cancer-research.com/content/16/3/R65

shelleym1

Thanks for the link. This stuff is just so confusing!

AnniebNJ

Thanks for the link. Very interesting, it seems with my high ki67 (30%), I would be considered luminal b. I guess that is what pushed me into the low intermediate range for the oncotype (19). Hopefully I didn't make the wrong decision regarding no chemo. Ugh, I will always be second guessing myself. Damn this disease.

tshire

AnniebNJ, The good news for you and me was that Grade 1 Luminal B is quite unusual had a very good prognosis even without chemo, according to that study. Figure 4 shows the hazard ratios for each grade by subtype. The discussion is particularly interesting:

"Despite being increased in number by our proposal, only a small proportion of luminal A–like tumors were defined as poorly differentiated (2.5%). Reciprocally, a small proportion of our redefined luminal B–like tumors were well-differentiated (4.6%). Such a pattern was observed in a previous study in which the intrinsic subtype assignment was based on gene expression profiling. Bastien et al. reported 14.1% poorly differentiated luminal A tumors and 9.4% well-differentiated luminal B tumors among women with locally advanced primary invasive breast cancer studied using the PAM50 gene set [8]. Interestingly, an accurate assessment of tumor grade remains a powerful prognostic parameter, though it is not included in any of the surrogate definitions for luminal tumors. In our present series, patients with G1 tumors belonging to the luminal B class had significantly better outcomes than patients with G2 and G3 tumors of the same class, despite the fact that almost 80% of the former group of patients did not receive any chemotherapy in addition to endocrine therapy. Conversely, patients with G3 tumors of the luminal A class had worse outcomes than those with G1 and G2 tumors of the same class, with HRs not different from the HR for patients with G3 tumors of the luminal B class, despite the fact that >40% of the former patient group did receive adjuvant chemotherapy. It is tempting to speculate that a more comprehensive surrogate definition of the luminal classes of tumors for clinical purposes could incorporate grade as a first discriminator (G1 for luminal A and G3 for luminal and biological features to define the luminal classes among the G2 tumors only."

AnniebNJ

Thanks tshire. Apparently grade 1 trumps ki67and I guess we're part of the 4.6%.