[Lani]

AIs seek to stop the conversion of testosterone to estrogen in order to avoid "feeding" estrogen responsive breast tumors (or cells related to them which take up residence elsewhere)--by "feeding" I am referring to encouraging/allowing their growth and spread

Chemotherapy often puts patients into early menopause (ie their ovaries stop secreting estrogen)--in some patients it is permanent, in others temporary

Some foods, cosmetics etc contain estrogen-like compounds which may enter the blood stream and act like estrogens on tumor cells.

Trying to determine if a patient is in menopause, if AIs are working or whether some other elements in the environment are causing an increase in the body's estrogen has been difficult because we do not yet have a totally reliable test for blood estrogen content.

Makes it hard to interpret results of some trials as to whether patients truly tok their AIs for as long as they were supposed to, whether AIs work equally in all,
whether other compounds are interfering etc.

Hope this helps!