breast cancer

I want to know why Arimidex is not yet largely used istead of Tomoxifen in the relevant cases?

The answer is simple... Because it's much more expensive

Arimidex is used to treat metastatic breast cancer. the use of arimidex for early breast cancer is not in the "Sal Briut" at this time but patients which have contraindications fotr treatment with tamoxifen are given Arimidex.