Hi Daisylou, what a hard decision you have to make for your Mum, I think as she has dementia you may need to discuss it a little more with others as it's so hard for those who have dementia to cope.  I don't know what stage dementia your Mum has but as my Mum had it I understand where you are coming from.  Mine had blood cancer and couldn't cope with the iv and blood transfusion, she didn't have the patience to sit for hours and we had to stop the treatment in the end.  I can't be much more help because your post is very short and we're not professionally trained we are just people looking after people with cancer or have it ourselves.  Maybe others will hop on and give their thoughts but I would investigate it further with the consultant in charge.  Best wishes from me, Carol x