Abstract:

The incidence of breast cancer is rising annually. Along with the broader implementation of tumor screening and increased health awareness, there has been a significant uptick in the diagnosis of early-stage breast cancer. Early-stage breast cancer is generalized to breast cancer without distant metastasis, which is compared to the concept of late-stage breast cancer. The aim of treatment for early-stage breast cancer is to achieve a cure. Treatment is guided by evidence-based medicine, following guidelines and consensus to administer personalized and precise therapies to patients. Clinical research, as the foundational evidence for these guidelines and consensus, brings more optimized treatment for breast cancer patients. According to the updates of domestic and international guidelines and consensus between 2022 and 2023, this review summarized and classified the important clinical studies that have changed the clinical practice for early-stage breast cancer. These studies were based on molecular sub-types and categorized into optimization of neoadjuvant and adjuvant treatment of early breast cancer, escalating and de-escalating of adjuvant treatment, and the optimization of local treatment. The studies related to the optimization of neoadjuvant and adjuvant treatment of human epidermal growth factor receptor 2 (HER2)-positive breast cancer included the PHEDRA study which aimed at the application of pyrotinib, a small molecule tyrosine kinase inhibitor (TKI), to neoadjuvant treatment, the ExteNET study which investigated adjuvant treatment of neratinib, and FDChina study which confirmed the efficacy and safety of pertuzumab and trastuzumab fixed dose combination subcutaneous injection (PH FDC SC). The primary study addressing the optimization of neoadjuvant and adjuvant therapy in triple-negative breast cancer (TNBC) was the KEYNOTE-522 study. In terms of escalating in adjuvant therapy, the APHINITY study evaluated the efficacy of pertuzumab added to trastuzumab in high-risk HER2-positive breast cancer. MonarchE and NATALEE focused on the efficacy of abemaciclib and ribociclib in patients with hormone receptor-positive breast cancer. The SOFT TEXT study focused on ovarian function suppression (OFS) combining exemestane or tamoxifen in high-risk premenopausal breast cancer. Descending related studies in adjuvant therapy included the PLAN B study confirming 6 cycles of docetaxel in combination with cyclophosphamide in HER2 negative early intermediate to high-risk breast cancer. Among the studies related to the local treatment of breast cancer, the ACOSOG Z11102 study explored the feasibility of breast conservation in multicenter focal breast cancer. The SOUND study explored the exemption from axillary surgery in people with low-risk breast cancer. The PRIME Ⅱ study explored the possibility of exemption from radiotherapy after breast conservation in elderly patients with low-risk breast cancer, and the IMPORT HIGH study compared different dose-escalated simultaneous integrated boost radiotherapy regimens after breast conservation surgery. The FAST-Forward study focused on hypofractionated breast radiotherapy. These studies provided robust evidence for the implementation of clinical practice and the formulation of diagnostic and treatment guidelines and consensus. In this review, we focused on the update of domestic and international breast cancer treatment guidelines, and the impact of these studies on the clinical practice for early-stage breast cancer.

Key words: Early breast cancer, Guidelines, Consensus, Clinical research