Question about Oncotype Test

I’m wondering who called you? I’ve heard that around 3 mm or so is the size they can start testing the sample. Seems like you’d have that on 17mm tumor. I imagine everything will check out, but I’d still do my due diligence by calling the people at Genomic Health, and also calling the pathology department where your mom’s sample is stored. Often pathologist are quite open to speaking with patients. I called my pathology department three years after the fact and the chief of staff volunteered to pull my slides and take another look that same day.

PS My doctor is among many who does not put a lot of stake in the ki-67 since it can be quite subjective.

There is not a lot of stock put into the Ki67 test since it can vary even between pathologists in the same lab. I, too, suggest making sure that the samples were labeled correctly. It seems suspect that they were able to test the micocalcifications and not the tumor. Was there any spread to the lymph nodes?

My tumor was 16mm, grade 2, strongly ER/PR positive (90% and 70% respectively), and my Ki67 score was 15%. I had micrometastasis and isolated tumor cells in the lymph nodes. My oncotype score came back at a 13.

I sympathize with the feelings of uncertainty. I would think, in this kind of a situation, that it might be good to get a second opinion. With a missing oncotype score, I certainly would.

The Ki67 test is part of the oncotypeDX test and is now standard in test results for your particular cancer. It isn't to be ignored. These days, the accuracy is much better with Ki67 whilst a lot of doctors poo-poo it based on results in "the old days"...things have changed and it is still very much relevant considering it is included in the OncotypeDX test.

General Information re Ki-67 Determinations by the Pathologist using IHC:

Ki-67 is a protein that is a marker of cell proliferation or cell growth (a higher percentage suggests more dividing tumor cells).

In general, rapidly dividing cells may be more responsive to chemotherapy. The 2015 St. Gallen panel commented on pathologic methods that detect Ki-67 protein:

>> "There can be little doubt that Ki-67 scores carry robust prognostic information [24], and that high values predict the benefit of addition of cytotoxic chemotherapy [25], but definition of a single useful cut point has proved elusive both because Ki-67 [protein] displays a continuous distribution [26], and as a result of analytic and preanalytic barriers to standardized assessment [27]."

In other words, despite the results of studies which report some prognostic and predictive value, there are technical issues with determination of Ki-67 percentages by standard IHC methods, including interobserver variability (different results when different people perform the test on the same sample) and lack of reproducibility across laboratories, as explained in detail here:

>> Polley (2013): "An International Ki67 Reproducibility Study"

>> http://jnci.oxfordjournals.org/content/105/24/1897.full

>> (Free PDF available via link)

Also, different clinical studies use different values as cut points or cut-offs between what is considered "low" or "high" Ki-67.

This can make it difficult to rely on the results of clinical studies in which Ki-67 was determined in other labs and/or to interpret the clinical significance of a Ki-67 test result based on such studies. Accordingly, some institutions no longer perform Ki-67 testing by IHC (at this time), and clinical consensus guidelines (e.g., from ASCO) do not generally support the broad use of Ki-67 protein (determined by standard IHC) to guide adjuvant chemotherapy decisions.

To ensure receipt of current, case-specific advice, patients should ask their Medical Oncologist for his/her views on the significance of their Ki-67 protein result and how it should be weighed in connection with their treatment decisions.

BarredOwl