Thanks both Roadrunner and Lyndu. When I was dx with underactive thyroid - just over 3 years ago not, doc told me that my hormones were affected - along with everything bythe underactive thyroid, eg periods were affected, and mood swings etc - like the menopause (apparently not had that yet, but have a feeling thats all coming on fast with the drugs - ho hum - which in turn made me wonder whether the thyroxin had any input to the bc I was dx with in june just gone. Well will ask the onc when I see him on 1st september (I had hormone receptors - which one dont know yet). My understanding is that both the bc and underactive thyroid are connected to autoimmune but maybe thats where the connection ends, Thanks again.
As far as I know, underactive thyroid isn't going to affect what drug you take for the breast cancer.
Whether there's a connection - I remember a breast care nurse telling me a long time ago that there was a statistical connection - ie more women with low thyroid have bc than in the general population - but no-one had come up with a causal connection. I have low thyroid - but I must admit I haven't followed it up. Low thyroid is very common in women over about 40, I understand. My onc certainly didn't express much interest in it as far as my treatment went.
I have an overactive thyroid - but the treatment for this is to suppress the thyroid function completely with carbimazole, then take thyroxine to replace what is missing. My thyroid went wrong 12 months before I was dx with BC. I have just stopped my thyroid medication, but was on it for 2.5 years - 12 months before dx and then all through treatment. This never had any effect on the BC treatment I was given (mastectomy, chemo, rads, tamoxifen, herceptin), and I have asked both my onc and at the thyroid clinic, and they all say that there is no connection between the two conditions.
The only difference for me compared with a patient without BC, was that I continued the thyroid medication for longer - the usual treatment for an overactive thyroid is to take tablets for 18 months, then stop and see what happens (50% of patients will be cured, 50% will relapse). As I was in the middle of chemo at the time, they decided to keep me on the thyroid tablets as they didn't want me to be having a thyroid relapse at the same time. I am now waiting to see if I relapse - not as bad as waiting to see if BC comes back, but still unnerving, as I really don't want to feel that unwell again.
Following surgery for tubular breast cancer I have been told (not seen the ONH yet) that I will have to have 5/6 weeks radiotherapy and adjunct treatment (hormone receptors on tumour) which may start even before the radiotherapy. Does anyone know if having treatment for underactive thyroid affects which drug you are given, or basically has any connection with breast cancer. Thanks