Hi,
My Mum has moderate stage dementia, and was diagnosed with breast cancer about a year ago. Mum has had cancer twice before and survived it, always being proactive with diagnosis and treatment.
This time, on consultation with the doctors, we decided the best option was to let Mum have the medication to treat the cancer rather than have the operation and other invasive treatment to remove it. This involves oral medication which 'fences in' the cancer for some time.
The consultant advised against another mastectomy, due to her experience of patients in a similar position. Ie , they don't tend to do well as regards their dementia, and nursing afterwards, understanding everything etc Although this was a difficult decision, we want Mum to have a better quality of life in the remaining time she has left.
Every person should be looked at individually, and there are possible side effects to any medicines.
Its not easy to have to make these decisions on behalf of a loved one, but we do the best we can, based on our love for them. I hope you come to the decision that you find the most peace with.
We don't always have 100% , but one decision will probably weigh down the scales as a better option for your mother.
I wish you and your mother all the best.