HR+, HER2– BC: Disease landscape and clinical management
How are women impacted by breast cancer?
Breast cancer (BC) is the most common cancer type, and the leading cause of cancer mortality, in women worldwide.1
HR+, HER2– is the most common subtype of BC, accounting for ~70% of cases3
Hormone receptor-positive (‘HR+’), human epidermal growth factor receptor 2-negative (‘HER2–’) BC is characterised by expression of the oestrogen receptor (ER) and/or progesterone receptor (PR), and lack of expression of HER2, in tumour cells.3
- Early breast cancer (eBC) is defined by tumours that have not spread beyond the breast or nearby lymph nodes,4 and comprises ~66–90% of all new BC diagnoses.5–7
- Early-stage tumours represent a biologically distinct disease state, characterised by lower clonal heterogeneity than advanced/metastatic tumors, indolent growth kinetics and disease confined to the breast and/or regional lymph nodes, with limited systemic dissemination.5,8-11
- Metastatic breast cancer (mBC) is defined by cancerous cells that have spread (metastasised) to other parts of the body. It is biologically more heterogeneous than early-stage disease, with increased clonal evolution, treatment-driven selective pressure and activation of alternative signalling pathways that contribute to therapeutic resistance and disease progression.9,12
References
- https://gco.iarc.fr/today/en/dataviz/bars?types=0_1&mode=cancer&group_populations=1&sort_by=value1&sexes=2&key=total (accessed March 2026);
- https://gco.iarc.who.int/media/globocan/factsheets/populations/900-world-fact-sheet.pdf (accessed March 2026);
- https://seer.cancer.gov/statfacts/html/breast-subtypes.html (accessed March 2026);
- https://emedicine.medscape.com/article/2007112-overview (accessed March 2026);
- Fasching PA, et al. Geburtshilfe Frauenheilkd 2024; 84:164–184;
- https://www.nationalbreastcancer.org/breast-cancer-facts/#:~:text=Approximately%2066%25%20of%20breast%20cancer,localized%20stage %20is%20over%2099%25 (accessed March 2026);
- https://digital.nhs.uk/data-and-information/publications/statistical/cancer-registration-statistics/england-2021---summary-counts-only/cancer-incidence-by-stage (accessed March 2026);
- Turner KM, et al. Am J Physiol Cell Physiol 2021; 321:C343–C354;
- Pasha N, Turner NC. Nat Cancer 2021; 2:680–692;
- Paik S, et al N Engl J Med 2004; 351:2817–2826;
- Sparano JA, et al. N Engl J Med 2018; 379:111–121;
- https://www.cancer.gov/types/breast/stages/metastatic-breast-cancer (accessed March 2026).
