Hi Susan. My Mother was diagnosed in March of 2009. After a lumpectomy, although the cancer itself was removed, following pathology, her surgeon wanted to go in again to take out additional surrounding tissue in order to have "safer margins" around the affected area. She chose, instead, to have a mastectomy. Also, she refused the suggestion of chemo and radiation. She began arimedix and was told she would need to continue for 5 years. Her most prevalent "side effect" was an overall decrease in body temperature, as well as some overall achiness. She discontinued taking it last October (2011), when she was diagnosed with stage 4 laryngeal cancer.