@buckokey Hang in there! The Letrozole may in fact be shrinking the ILC tumor for lumpectomy surgery which is why it was recommended. HOWEVER mastectomy is often recommended for ILC because ILC is so diffuse and surgery gets clear margins.
I wanted a lumpectomy too, but finally accepted that I needed a mastectomy which showed positive pathology margins (not clear). Then chemo to kill whatever cancer cells were left, a second surgery to get negative margins (clear pathology) and radiation. Because the ILC was so sneaky, I'm very happy that it's out and did not have any reconstruction. Honestly, I am glad to have had a mastectomy as there's no residual ILC. Now I'm on Anastrozole to prevent a recurrence and I'm doing my best.
So to answer your question, the Letrozole may in fact be shrinking everything so that you CAN get the lumpectomy, but if you need a mastectomy, please accept that the most important thing is that it's so important to get it all out because your life is a blessing and you are a most important part of this world.