Does Oncotype apply on young women with larger tumor size?

Yes, the Oncotype score does apply to your situation. That said, given your young age, if possible it would be beneficial to see more than the generic results that are given to everyone, but instead see results that are adjusted to reflect your age.

While the Oncotype test is meaningful and does have prognostic value, to my understanding, the other factors that have prognostic value are tumor size, tumor grade and patient age. Genomic Health (the company that does the Oncotype test) have a computer program available only to Medical Oncologists that allows the MO to input the Oncotype score along with those 3 factors, to determine a recurrence risk figure that is more specific to the individual patient. It's called "Recurrence Score - Pathology-Clinical). A couple of people on this site have mentioned that their MOs used this program, as did my MO. In the situations I am aware of, the patients had very favorable factors (older age and/or good pathologies) and their recurrence risks ended up being significantly lower than the Oncotype score alone would have suggested. I don't know if this program is also used on patients who are younger and who therefore might end up with a higher risk than indicted by the Oncotype score alone, but I think you should ask your MO about this. Perhaps he has already run the program, which might be why he is recommending chemo. If not, perhaps he can run this program for you (or explain if it is not applicable or appropriate in your situation).

Don’t forget that chemo can cause harm to healthy tissues as well as cancer cells. My understanding is that the oncotype score helps to determine if it might cause more harm than good. Getting chemo “just for good measure” could cause unnessary lasting side effects. I suggest you get a third opinion or talk to a nurse navigator to get a better understanding.of oncotype. Unfortunately, with this disease we have no guarantees.The elephant in the room is that oncologists get paid well for prescribing chemo and that can unconsciously affect their judgement. I found a long article written by an oncologist about this so it s not just my admitted paranoia.

I think if I had results like that I'd want to get the Mammaprint test done as well as Oncotype.

I'd also spend a lot of time on the Predict website looking at the charts and stats with the various options and meditating on what I value and how I think about things. https://breast.predict.nhs.uk/predict_v2.1/

fwiw, I didn't have to make this choice with chemo but I had to with tamoxifen/AI as I'm only very slightly ER+ and there is a lot of confusion about whether hormonal tx helps people in my boat or whether risks outweigh the benefits. There are things for which we just don't have a lot of data and we have to be ok with a fair bit of uncertainty, as well as considering how much you can modify your other factors (diet, exercise, alcohol, smoking, stress).

Once you make a decision, don't look back. Just leap in and don't look back at all. Whatever happens in future, you'll deal with it then.

Soffee, here is more information about the additional Genomic Health tool (RSPC) that some Oncologists use to assess and personalize Oncotype scores:

https://ascopubs.org/doi/abs/10.1200/jco.2014.32.15_suppl.570

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5847032/

I understand your worries about your treatment plan.

I had 3 tumors, biggest 1.9. But with micromets. And LVI. I am on Tamoxifen since my mastectomy in august. January I took my ovaries out( own initiative) and in november I did rads 15 times. There was no way I could get chemo-of course at some point skipping chemo made me feel like I was in danger! I had 2 grade one tumors and one grade 2. My oncologist said: you will not benefit from chemo.

Good luck on your decisions dear,

Monique(Netherlands