Switching from letrozole to Tamoxifen?

Congratulations on reaching that milestone as 5 years of Femara must be rough.  I am on anastrazole but early in treatment.  Just over 3 months but doing ok except for really bad dry mouth during night snd s little fatigue now snd again.  I read that Femara depletes estrogen more than anastrazole.  
since you have finished 5 years of the AI have they offered you to take the Brest cancer index test to see if 5 more years will benefit you?  Since my bilateral breast cancers were small and caught early medical oncologist told me 5 years should be enough snd I am 73 so that makes a difference too.  The ER+ cancers are known to come back years later but I don’t know about the stats.  Wish you the best .  You are doing good snd s real trooper to finish medication when you didn’t feel like it.  
Barbara