Another Oncotype question

ER/PR 3+ (Very high), No LVI identified, Ki-67 15%, Oncotype score 21.  Decided against chemo, will have hysterectomy next week and start 5+ years Arimidex right after.  Since my BC is so hormonal, I'm hoping that taking all my estrogen away will in itself prevent recurrence.

This is very interesting.  I find out my oncatest results on Thursday.  My oncologist said she didn't think I will need chemo.  She didn't say why she thought that.  If it comes back that I don't need it, I will ask her why she thought I wouldn't need it.  Maybe we can start to see a pattern.

I'm highly ER positive, and my oncotype came back at 25 which is smack dab in the middle of the intermediate range.  My MO was surprised.   I ended up having neoadjuvant chemotherapy and I still had 2 positive nodes.....although my tumor did respond fairly well to the chemo, not great, but there was a response.   As we have been told, estrogen positive breast cancers don't respond very well to chemotherapy, if they are grade 1 or 2. I am pretty certain there isn't a correlation between node status and oncotype, correct???   But, it says something about the DNA of my particular tumor, possibly??  Or maybe I've had this cancer in my body for a long time and it was very slow growing......I remember on the day I was diagnosed someone saying (the radiologist I think) that my tumor was probably there for 3-4 years.......I think it might have been there even longer?   It's such a mystery....a very scary one at that!   I'm obviously concerned.  I'm hoping Tamoxifen and AIs will be the key to my treatment. 

I am strongly positive ER/PR (100% both) with oncotype 29. I agree with others they're not necessarily related.

This question of a relationship between ER positivity and Oncotype DX score is an important one. Two years ago, some of us were discussing the effect of being PR negative, and how that might influence our Oncotype scores.  Here's what I found back then.  I've edited my original comment so it's relevant to those of us with strong ER reactivity, which I also had.  Keep in mind that the results of traditional ER histologic testing (immunohistochemistry) doesn't necessarily correlate well with results of the testing done by Genomic Health Inc.  Okay, here goes...

In the formula used to calculate the Oncotype DX score, the ER result (the amount of ER gene expression) is included with a group of genes that are associated with less aggressive tumor growth and, therefore, lower risk of recurrence.  Other genes in that group (the "ER Group") are PR, Bcl2, and SCUBE2.  Because those genes are considered "good" proliferation genes (high expression of those genes is associated with a lower risk of metastasis), their combined value is multiplied times a negative multiplier factor ("-0.34") in the Oncotype DX formula.  When all the numbers that comprise the Oncotype DX score are combined, the value of the "ER Group" genes is subtracted from the total (because of the negative multiplier factor).  So, that means higher ER gene expression, and/or higher PR gene expression (etc.), produces a lower Oncotype DX score.  Conversely, the lower the expression of the ER and/or PR genes, the higher the Oncotype DX score.

The opposite is true for the proliferation genes that are associated with rapid cell growth and greater risk of recurrence.  Examples of those genes are Ki-67 and HER2 (and a bunch of others).  Their expression scores are multipled times a positive multiplier factor.  So, the higher the expression of Ki-67 and other genes in that group, the higher the Oncotype DX score; and the lower the expression (or if they are not expressed at all), the lower the score.  For instance, that's why someone whose tumor is HER2+ will usually have a high Oncotype DX score.

Here's an image from Genomic Health's website (http://www.oncotypedx.com/en-US/Breast/HealthcareProfessional/~/media/Images/Basic/Breast/HCP/Proliferation.ashx?w=708&h=226&as=1) showing the grouping of the individual components of the Oncotype DX test and the multiplier factors used to calculate the score.

 This is why someone who is strongly ER+ is likely to have a low Oncotype DX score.  That's not absolute, though, because all the factors contribute to the result.

otter

Thank you Otter!  I was hoping someone would post with clearer info for those who had yet to get the details to understand the relationships between ER, PR, HER2, and Ki 67 and the Oncotype score.  I'm always surprised when members report that their MO thinks their score will be low and their pathology reports seem to indicate otherwise.  Is this just to keep a patient calm?

 After doing this research, I knew my score would very likely be mid to high intermediate and it was 1 point from high risk.   My PR (5%), HER2 (+1)  and Ki 67 (40%) highly impacted the score.   

So Anndh - Are you saying your biopsy specimen came back with the triple negative status and then when you had your lumpectomy it came back with the completely different numbers??   Yes, please let us know about your oncotype score!

I was 99% ER and 95% PR.  Oncotype was 8.

Otter



I love your detailed explanation of oncotype. This board is great Where did you find this explanation? I had oncotype done even though I'm stage III with one positive node. I had 16 cm tumor. I think my MO wanted conformation as to how I could have such a large tumor with initial metastatic work up negative. I'm going on 2 years since dx. Hopefully I really am middle aged with another 53 years to go.

txmom of two...gosh I would totally get a second opinon.

With a 1% KI67 .... I just don't see much indication chemo would work, unless they are concerned the foci have different characteristics.

Elizabeth1959, the website for the company that does Oncotype DX testing (Genomic Health) has a section explaining the technical basis of Oncotype DX testing, and how the researchers came up with the Oncotype DX formula:  http://www.oncotypedx.com/en-US/Breast/HealthcareProfessional/Underlying.aspx

I do a lot of reading of scientific and medical articles.  When I was in those waiting stages during my "cancer year," I had quite a bit of time and incentive to read.  So, I dug up the journal articles in which the development and validation of the Oncotype test was reported, and I read them.  They contain more detail than what's on the Genomic Health website, but the website provides a pretty good summary.

txmomof2, it's possible that, with a multifocal tumor, the test results from one of the lumps might be different from results on the other lumps.  And, test results from one part of a single lump can be different from another part. The fact that your results were the same on the biopsy as on the tumor removed at surgery is good; I think most med onco's would base their treatment recommendations on those results. But, you're right -- your med onco is probably playing it safe by worrying that one of those other lumps might be a whole separate tumor.

I think a 2nd opinion (at least) is essential when there are these types of questions.

otter

So what is the range for the ki67 score?  What is low, mid and high?

anndh, That's what I had to do TC x 4, then rads.  Out of curiosity, do you know the staining on your ER and PR?  Highly, moderately, or weakly?