Hi Gladys58,
I haven't had to go through chemo, I had stage 2b, grade 2 (4cm) + multiple dcis. I had bi-lateral mastectomy and full node sweep, and radio with Hormone therapy ongoing (early menopause and all that), but for me the question was not so much what % improvement, but from what to what? ie, are you looking at improving risk of recurrence from 5% to 2% or is it 20% to 17%.
What overall level of risk are you assessing. that helped me to choose when it came time. maybe your oncologist/ breast care nurse or gp can help give you that number that you feel good with.
Good luck with your decision.
Aine