@Sirrah - Initially my breast surgeon said i would be onTamoxifen, so assumed that was what I would go onto! (Shows how much THEY know about hormone treatment!) Tamoxifen has been around for decades & is one of the best known hormone treatment tablets!
However - From my first visit to the Onc - Tamoxifen was never suggested, so I asked her why?
I took notes! (Please correct me if I've got this wrong, ladies!)
Oestrogen is produced in the ovaries until menopause, and then post menopause, it is continued to be produced by a fat hormone (aromatase) to keep the level 'up' - but it should by then be a lesser level than in Pre Menopausal women.
Tamoxifen is a Selective Oestrogen Receptor Modulator. If the pathology showed the cancer was Oestrogen Positive - the oestrogen is feeding the cancer in the breast & it is blocked by the Tamoxifen - often given to PRE Menopausal women or those forced into menopause by chemo as their levels are still quite high in the body.
AIs (Aromatase inhibitor - i.e. the hormone that is producing oestrogen from the fat tissue) eg, Femara, Arimidex, Letrozole, Anastrazole - blocks that chemical reaction in the fat - so is often given to POST menopausal women.
Different Hormone Tablets affect different women differently! Some have massive side effects whilst others have virtually none. I don't think they know exactly why this is so - tho research into it should be vital - to try & determine which one will suit which woman/man better right from the start of treatment. Up til now, I think it is trial & error, to be honest.
So I started on Letrozole. I already have had quite severe arthritis for 20 years (and I have a reasonable tolerance of pain level i.e. I am used to the pain and don't take many tablets for it!) But within a week of being on Letrozole, I was in massive pain & taking daily anti-inflam tablets - my whole body, but specifically my feet and hands. They just ached & hurt 24/7. My body just didn't want to work properly - getting out of bed or a chair was painful & awkward - and also made me more likely to have a fall. I put up with it for 6 weeks - and at my Onc Review - told her of my agony. She immediately suggested I try Exemestane which I started the next day. When I saw her again 8 weeks later, she was happy for me to stay on it, as most of the bad side effects I was having from Letrozole had virtually stopped.
On the flip side - some others on the forum have NO real side effects from Letrozole ..... and it is considered one of the best oestrogen blockers, so if it is suggested that you try it - DON'T BE AFRAID TO GIVE IT A GO!! It may be perfect for YOU!
All the best for your continued treatment xx