Metastatic Breast Cancer: An overview of supportive care needs

Background: Globally, breast cancer is the most common diagnosis in new cases of cancer, with 2.26 million new cases diagnosed in 2020. 1 Breast cancer treatment can be highly effective, especially when the disease is diagnosed early. Mortality rates have been on a steady decline in recent years in high-income countries, largely due to advancements in population screening programmes and early-stage treatments. 2 Metastatic breast cancer, also known as stage IV or advanced breast cancer, is rare as a primary diagnosis, making up 6-10% of new cancer diagnoses. Metastatic breast cancer has a current 5-year survival rate of 25-27% 3,4 , and is considered an incurable disease caused by the spread of breast cancer to other areas beyond the lymph nodes of the axilla to other sites in the body. 5,6 However some patients (estimated at 10%) will attain long-term disease control, or undetectable disease, and thus achieve a prolonged survival. 7

Improved survival rates for metastatic breast cancer have come predominantly as a result of advances in therapeutic options including targeted therapies, immune checkpoint inhibitors and antibody-drug conjugates. 2,5 Novel agents targeting the oestrogen receptor (ER) and human epidermal growth factor receptor 2 (HER2) pathways, and the tumour microenvironment have been associated with improved survival outcomes; although adverse event profiles and response to therapy can vary between individuals 8,9 . As such, there has been a notable extension in survival time for patients with metastatic breast cancer, though it varies by the clinical, pathologic, and disease characteristics and extent of metastasis.