Exploring the concepts and practices of advanced breast cancer treatment: a narrative review

OBJECTIVE: To explore the concepts and practices of advanced breast cancer treatment. BACKGROUND: Metastatic breast cancer (MBC) has become a chronic disease, with a median overall survival (OS) of around 3 years and a 5-year survival rate of about 25%. OS are strongly associated with the best available care, which consists of not only application of guidelines, but also multidisciplinary specialized care, the most efficacious medicines, and so on. Advanced breast cancer (ABC) Guidelines are the most important and authoritative guidelines for MBC. METHODS: In this review, we demonstrate the history and evolution of the global ABC Guidelines. Since 2015, Chinese multidisciplinary experts have drafted guidelines for clinical diagnosis and treatment of MBC. All of these ABC guidelines describe specialized therapeutic principles for different subtypes MBC in detail. Encouragingly, we have found that some special subtypes are hopeful of being cured, such as HER-2 positive patients with low tumor burden or HR-positive (HR+) MBC with non-visceral metastasis. In our opinion, the definition of cure of MBC is that MBC patients achieve CR and remain for more than five years after systemic treatment, including those with local therapy. Consequently, we also have conducted some researches and meaningful explorations in different subtypes of MBC. In HER2 positive MBC, our study revealed that regular HER2 circulating extracellular domain (ECD) assay can provide the real-time monitoring of tumor burden and prediction of poor outcome, and may present an important opportunity to reassess HER2 status. In HR+ MBC, we suggested that hormone therapy (HT) maintenance is the priority choice for HR+/HER2− MBC after first-line combined chemotherapy. Besides, our real-world study revealed that fulvestrant combined with ovarian suppression was an active option for premenopausal HR+/HER2- MBC. And also, we observed that everolimus (low-dose) combined with hormone therapy was still effective for HR+/HER2− MBC. For mTNBC patients, we found that THA and endostatin exhibited potential efficacy and was well tolerated in pretreated patients. CONCLUSIONS: Our concepts and practices will contribute to the design of relevant clinical research and accumulation of evidence, and cure of MBC is promising.