AIs prevent body from making estrogen. Exemestane is steroidal and irreversible, so it tends to have long term effect compared to Anastrozole. I will ask my onco about photoestrogen effect in breast cancer. I found this article about this article about phytoestrogen effect on breast cancer, the conclusion is particularly interesting. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9776930/
I also remember reading some where that low breast cancer in Asia is linked to high consumption of soy.
" In conclusion, in this review, none of the selected studies found statistically significant adverse effects of soy consumption on BC recurrence or mortality (specific or all-cause). Almost all studies showed beneficial effects of soy isoflavone intake, in variable ways, on BC recurrence and mortality. These results coincide with other recent works and suggest that soy isoflavone intake is safe for BC survivors.

However, in order to confirm the current results, larger studies are needed. Future research should have larger sample sizes, more accurate assessments of soy isoflavone intake (and total phytoestrogen intake), better control of confounding factors, and longer follow-ups."