If one is ER+ and has ESR1 mutation, it is possible for "cooperative" oncologist to use Elacestrant even if one is Her2+, especially when there is no endocrine regimen left.
Elacestrant vs fulvestrant or aromatase inhibitor (AI) in phase III trial evaluating elacestrant, an oral selective estrogen receptor degrader (SERD), vs standard of care (SOC) endocrine monotherapy for ER+/HER2- advanced/metastatic breast cancer (mBC): Subgroup analysis from EMERALD
https://www.annalsofoncology.org/art...110-X/fulltext