Premedication with steroids in breast cancer - supportive treatment or tumour growth promotion?

Glucocorticoids, most commonly dexamethasone, are widely used alongside breast cancer therapy to alleviate adverse effects of chemotherapy, particularly allergic reactions and nausea. However, growing evidence shows that the activation of the glucocorticoid receptor (GR) has context-dependent effects on tumour biology, with both tumour-suppressive and tumour-promoting consequences. This review summarises the molecular basis of GR signalling in breast cancer and its prognostic relevance across molecular subtypes. Particular emphasis is placed on ligand-dependent and ligand-independent GR activation, crosstalk with the oestrogen receptor and GR-regulated transcriptional programmes associated with tumour cell migration and therapy resistance. Overall, the available evidence suggests that the use of glucocorticoids in triple-negative breast cancer is not biologically neutral. Assessment of GR using methods such as routine immunohistochemistry may add future value for patient's stratification for GR-targeted therapy and could inform more personalised supportive treatment and follow-up strategies; however, these approaches require prospective validation before clinical implementation.