Elacestrant is a precision targeted anti-cancer drug with clearly defined biomarker restrictions and is not broadly indicated for all cancer types.Its core indication is for the treatment of hormone receptor-positive(HR+),human epidermal growth factor receptor 2-negative(HER2-)advanced or metastatic breast cancer,demonstrating significant clinical benefit particularly in patients harboring ESR1 gene mutations.

　　Within the molecular classification system of breast cancer,estrogen receptor(ER)-positive disease is one of the most common subtypes.The growth of these tumors is highly dependent on the continuous activation of the estrogen signaling pathway,making endocrine therapy the cornerstone of treatment for this patient population.However,with prolonged treatment,some patients will inevitably develop endocrine resistance,and activating mutations in the ESR1 gene represent one of the key mechanisms driving this resistance.These mutations cause the estrogen receptor to remain constitutively active even in the absence of estrogen,leading to significantly reduced efficacy of traditional endocrine agents.

　　As a next-generation oral selective estrogen receptor degrader(SERD),elacestrant is specifically designed to target this resistance mechanism.Its unique dual mechanism of action involves not only competitively blocking the binding of estrogen to the estrogen receptor but also effectively promoting the degradation of the estrogen receptor itself,thereby cutting off aberrant estrogen signaling at its source.This mode of action gives elacestrant irreplaceable clinical value in patients with ESR1 mutation-related endocrine resistance.

　　The eligible patient population for this medication includes postmenopausal women or adult men with breast cancer who have experienced disease progression following at least one prior line of endocrine therapy.This means that elacestrant is primarily used in the second-line and later-line treatment settings in the continuum of breast cancer management,providing a new therapeutic option for patients who have failed traditional endocrine treatments.

　　It is particularly important to emphasize that elacestrant has highly specific indications.It is not indicated for HER2-positive breast cancer,triple-negative breast cancer,or other molecular subtypes of breast cancer,nor is it used to treat any non-breast-derived malignancies,making it a prototypical example of precision targeted therapy based on molecular profiling.

　　From the perspective of global breast cancer treatment trends,individualized precision therapy based on molecular profiling has become the mainstream direction.The advent of elacestrant represents an important therapeutic advance in the field of endocrine resistance,bringing longer survival benefits and improved quality of life to patients with HR+/HER2-advanced breast cancer,especially those with ESR1-mutant resistant disease.