To clarify for you, the grade 2 refers to the s phase, or how many cells are reproducing at any given time within a tumor. This would be middle of the road, 1 being the least aggressive and 3 being the most aggressive reproduction in cells.
The 1a or 1b would be the stage of your cancer, this refers to how advanced it was, with stage 0 being in situ or encapsulated. Stage 1 would refer to a tumor 1cm or smaller with no node involvement. Definitely a preferable stage. Stage 4 being the worst meaning metastatic disease.
@windyshores is awesome at helping to decipher the tests. I am so glad she is here for all of us.
I agree with her and others about having a conversation about your endocrine therapy with your doctor. There are quite a few options that could be considered.