Accuracy of Oncotype DX Test!!

MsShelly:  I am not a scientist, nor do I play one on TV.  But, I had some discordant results between my biopsy and Oncotype test, so I've been asking lots of questions and getting (what I think are) answers along the way.

In a nutshell:  my biopsy showed Grade 2 (moderately differentiated) ER/PR+ Her2-.  I've got the path report and it's pretty straight-forward.  My Oncotype test came back at a 42, which indicates high Ki67 proliferation (my original path does not include a Ki67 test), and my tumor was detailed as barely ER+ (6.6 on a scale where 6.5 is the cut-off for negative), and PR- and Her2-.  So, am I positive, or negative?  Am I in a "good place" (1.3cm tumor, Grade 2) or in a "bad place" (high Ki67, high rate of recurrence?)

For planning purposes (treatment...and life...) I tend to side with the Oncotype test results.

My MO says that in general, the Oncotype test confirms what the path report details.  Path comes from a specific area of the tumor, but since the understanding is that most tumors are homogenous (they're pretty much the same through-and-through), what you're getting is a representative sample.  Oncotype grinds up the sample and then tests genetic markers - so it's like a tumor smoothie, and you might find something in that that you didn't find in the original path sample.  While I have yet to be able to find a peer-reviewed article that confirms this, what I've been told is that the huge difference between path and Oncotype often happens when there is an aggressive cancer involved.  With a 42 Oncotype score, I have an 18% recurrence rate with chemo and five years of Tamoxifen.

But for what it's worth chemo doesn't promise non-recurrence, for someone with a score of 42 - or 10.  For you, the risks of chemo far outweigh the benefits - even if it that doesn't seem to be the case.  I mean, conventional wisdom says that if you have chemo you'll be that much safer from recurrence, right?  It can be hard to believe that forgoing chemo may actually be better for you.

I'm hoping someone else with a wealth of knowledge comes along and has a better explanation than I do. I don't know if I've helped at all.

This happened to me too. My original path showed ER+ (about 30percent) stage 1 grade 3, node negative. K167 like 140.

Had the oncotype. First go-around they couldn't get it from my biopsy. Sent a piece of my tiny tumor. Got a 38 on that- but their RNA test said I was ER negative. Like you, some smidge under the <6 or whatever. So was the oncotype valid? Am I ER positive ? Should I be taking Aromasin? Which I am, by the way. My doctor said I was ER positive via the IHC staining. If you look at the oncotype results it does say positive either by Their test OR IHC.
<br />So I did have chemo, am taking Aromasin , and hoping. It all makes me very grumpy.

Allie, you could go either way, but if it were me I would probably do the chemo. Do you how much your recurrence rate is reduced by chemo?