Hello bicycle-woman and thanks for your post,

There was a trial called Poetic that was looking at these questions whether it would be better to give endocrine therapy before treatment. 

You can read about the Poetic Trial results here. It is not completely straightforward as the trial shows that having endocrine therapy benefitted  some women.

The trial took tissue samples (biopsies ) before and after surgery to look for a protein in the cells called Ki67. They used this as a biomarker  to find out how well treatment was working. You can see the results above.

Sometimes hormone treatment is given to reduce the size of the cancer as it sounds likely in your case. 

I can't really give you percentages as there are so many different variables and different types of breast cancers.

Your own doctors are probably best placed to try and give you that information as they have all your medical notes and can give their opinion based on your pathology which includes the .stage and grade of breast cancer. You could also see if you could have a discussion with your breast care nurse at the hospital before you see the doctors at your appointment next week.

You are very welcome to ring and chat through this with one of the helpline nurses here.  The number to call is Freephone 0808 800 4040 and the lines are open from 9am till 5pm Monday to Friday.

All the best,

Catherine