Endocrine Therapeutic Strategies for Patients with Hormone Receptor-positive Advanced Breast Cancer

Abstract

Endocrine treatment constitutes the therapeutic backbone for patients with oestrogen and/or progesterone receptor-positive breast cancer unless there is visceral crisis or suspected or known endocrine resistance. Whether all patients who are suitable for endocrine therapy should receive combination therapy or whether there remains a role for single-agent endocrine therapy is yet to be determined. Cancer biology (ESR1 mutational status) and disease pattern determine the choice of single-agent endocrine treatment. Possibly, patients with low disease burden, slow progression and presumed endocrine sensitivity might still be considered for single-agent endocrine therapy, whereas patients with more aggressive disease including visceral metastases might benefit from combination therapy. Improved guidance on selection and sequencing of treatments should become available once overall survival (OS) and progression-free survival (PFS) data have been reported from the ongoing trials in breast cancer, principally, FALCON (NCT01602380), PALOMA-2 (NCT01740427) and MONALEESA-2 (NCT01958021), which include different patient groups and, probably, different endocrine sensitivity.