Hi CLKD, I so agree that quality of life is the key.
My mum had a successful breast cancer surgery in December with a diagnosis of it being Oestrogen sensitive and was subsequently started on Letrozole. Since then she's had thinning hair, poor appetite, abdominal pain/nausea, joint/muscle pain, dizziness/losing her balance and the most troublesome to her, low mood and anxiety.
She is now on medication to try and help with the anxiety and is taking pain killers but she's so reluctant to go out anywhere and gets lonely at home.
We saw her Consultant this week. I had printed out information from a cancer specialist website about the Letrozole side effects to discuss with mum and she did talk to him about them. I also said how she did not have the same quality of life at the moment. He did acknowledge the tablets cause most of those symptoms but he was adamant he wanted her to take the Letrozole. And my mum will only do what the doctor tells her, especially as some of her anxiety is focused on the cancer coming back.
I will follow up on your suggestion though and try and find out whether there is a different tablet, until then I guess that I'll try to be supportive