An athlete must ensure that all substances prohibited in-competition have been completely cleared from his/her body before an event period. This means the substances are not detectable in the athlete’s sample. It is not possible for USADA to list specific stop times for substances prohibited in-competition. If the on-going or daily use of a substance is needed, or the medication cannot be stopped before an event long enough to allow it to clear from the body, an application for a Therapeutic Use Exemption (TUE) should be submitted.
As for how long you’ll take it - news at 11. At this point, all of us taking AIs are guinea pigs. ( Physician’s Note : Doctors might interject here that taking an FDA approved drug after an informed discussion with a licensed and treating physician does not meet their opinion of “guinea pig.” Participating in important clinical trials can make a significant different in the way we treat breast cancer, so don’t let fear of being a “guinea pig” dissuade you from making an otherwise informed choice about clinical trials ). Is 5 years best for aromatase inhibitor use? Is 7 years better? How about 10 years? There just hasn’t been sufficient data collected (yet) to draw hard and fast conclusions. You’ll probably be on your AI for 3 years minimum, if you’re switching over from tamoxifen; or for 5 years minimum, if you haven’t taken tamoxifen. Beyond that, who knows? By 2 or 3 or 5 years from now, more studies will have been completed, and there’ll be better data on which your oncologist can base his recommendations. Good luck!
Research suggests the common table mushroom has anti- aromatase  properties and therefore possible anti-estrogen activity. In 2009, a case-control study of the eating habits of 2,018 women in southeast China revealed that women who consumed greater than 10 grams of fresh mushrooms or greater than 4 grams of dried mushrooms per day had an approximately 50% lower incidence of breast cancer. Chinese women who consumed mushrooms and green tea had a 90% lower incidence of breast cancer.  However the study was relatively small (2,018 patients participating) and limited to Chinese women of southeast China.