Tamoxifen?

I have been taking Tamoxifen for ADH. I don't have BC nor have I had it. I'm taking the Tamoxifen due to the ADH and my high risk. My question is: My oncologist said that he would like for me to stay on the Tamoxifen for the "5 years" as long as no side effects..... I know it's hard to look into the future but lets say in 10 when I'm 46 I get breast cancer, could I take the Tamoxifen again.? Or What about women who have take Tamoxifen and finished their 5 year tx, and end up with breast cancer 2 years later or either they have a recurrence of BC. would the Tamoxifen be an option with the chemo. If it warrants??
I also want to thank you for this site, even though I don't have BC just ADH (atypical ductal hyperplasia), I find this site very helpful. Thanks again.

[CCF-RN,MSN-JS]

Dear Rfrancis, Whether or not tamoxifen would be recommended would depend on the situation.  Such variables as the amount of time that has elapsed, hormone receptors on the tumor etc. would need to be taken into account.  Also there are other types of hormone therapy (aromatase inhibitors) that are now available that could be used instead of tamoxifen.