Tamoxifen
"I am going on 5 years taking this medication religiously.  I was diagnosed with Stage 2B ductal carcinoma, invading my chest wall and 3 lymph nodes in 2008. So far, cancer free. The side effects are minimal. My skin is drier and I do feel aged but I also had my ovaries removed after testing   for BRCA2 so I think it might be due to that also. I want to continue taking for another 5 years since I'm only 34."