Help understanding diagnosis

KeepingCalm

I am 39 and I had a successful bilateral mastectomy and immediate implant reconstruction 3 weeks ago with no positive lymph nodes and clear margins. Here are the stats of my diagnosis: Oncotype Dx score 17

- 13 cm (crazy) of DCIS and IDC 1cm - Stage 1b

- pathology: ER+ (>90% strong staining) and PR + (1%, moderate staining) and HER2 negative

- Ki67<5%

- Oncotype Dx score 17

The tricky thing is I participated in a clinical trial of Ibrance (palbociclib) for 12 days prior to mastectomy and so my oncologist suspects that that may have shrunk the tumor (although on ultrasound and MRI it wasn't listed as much larger) and also possibly made my Ki 67 (<5%) lower than it would have been to begin with in turn possibly lowering the Oncotype score.

Does anyone have any idea how much the palbociclib might have influenced these numbers in just 12 days? Also, my oncologist seemed concered about such a low PR positivity. Does anyone have any input on that?

Anyone have experience with low PR+? 4 cycles of TC chemo is being recommended followed by endocrine therapy. I'd love to hear anyone's thoughts or experiences with all of this!

Chemotherapy is being recommended as a result of my age, the PR, and the concern that the trial may have made the Ki67 and Oncotype artificially low. I'm not looking to decline chemotherapy just to understand to what degree the palbociclib could have made a difference in such a short time.