Need a ONCO DX test but was started on letrozole before surgery

Update March 18, 2023: I've read all the responses and gained good information from you all on my journey. I know now that my surgeon and oncologist were aware of needing to preserve tissue for the potential need for an Oncotype DX test however, the glitch occurred when they assumed my multiple biopsies (I think 6 in total) taken prior to surgery would be "more than enough tissue" for the Oncotype DX test, thus not concerned about starting the letrozole prior to mastectomy. What the doctors didn't understand is the Onco test needs a minimum of a 2 mm untouched, continuous piece of tissue for each test sample. I have educated them on this. A total of 5 out of 6 of the biopsies throughout my breast were known as positive. Once this was determined and 2 more non-biopsied highly suspicious tumors were identified, there was no reason to perform yet another series of biopsies as I made the recommended decision to have a double mastectomy. I was started on letrozole 5 weeks prior to surgery but only after all, biopsies were completed. All tumors and cancerous tissues from the mastectomy were, therefore, not viable for an OncoDx test.
So, here I am 10 months from diagnosis and 7.5 months post-surgery. After speaking to multiple oncologists around the country, U of Chicago Oncology Professor, and contact with the Oncotype DX engineers/scientist, they unanimously affirmed, I would never be able to have the Oncotype DX testing performed. The great news, without exception from all consulting physicians/scientists, was that most of my known breast cancer findings are very much in my favor.
I have come to terms with my situation and have adopted a seriously positive view of my prognosis. I am starting to feel like myself, energetic, full of life energy for the first time in 5 yrs. I had suffered unexplained, increasingly severe fatigue starting 5 years ago. Interestingly, I was told by all that based on my cancer's slow growth, it also started about 5 years ago! I am changing my lifestyle, exercise, and diet. I am taking charge of the things I can. I now view this problem as a blessing in a scary disguise. I may have dodged a painful bullet with chemo. I am at peace with my lot now as I have exhausted every and any avenue of rectification.
I thank you all for your interest, care, and great information. I wish you all peace and wellness in your journeys through this difficult "bump" in the road.

I am very glad that you taking charge of the things you can! In terms of changing lifestyle, exercise and diet, would you please share more details on them? How and what do you do? I really want to improve myself to a healthier life style too. Best wishes!