Breast cancer, as the most common malignant tumor globally, has been a hotspot of research for many years. In 2023, significant progress was made in clinical research on breast cancer in both local and systemic treatments. In terms of local treatment, evaluating axillary tumor burden and selecting appropriate treatment methods have been the focus of research. The SOUND study found that sentinel lymph node biopsy (SLNB) and axillary surgery had similar 5-year distant metastasis-free survival rates for patients with early-stage breast cancer who were negative for axillary lymph nodes on preoperative axillary ultrasound, avoiding SLNB when preoperative ultrasound screening results for axillary lymph nodes were clear. The SENOMAC study provided evidence supporting the possibility of not performing axillary lymph node dissection (ALND) for patients with low-burden sentinel lymph nodes. The OPBC05 study indicated that ALND did not improve long-term survival in patients with residual isolated tumor cells (ITCs) after neoadjuvant therapy, suggesting the feasibility of exemption from ALND. The NSABP B-51 study showed that regional lymph node irradiation (RNI) for axillary lymph node-negative patients after neoadjuvant chemotherapy (NAC) did not significantly improve the primary study endpoint. These studies emphasized the importance of personalized treatment regimens, providing important guidance for the surgical and subsequent treatment of breast cancer. In terms of systemic treatment, early-stage hormone receptor-positive [HR(+)] breast cancer treatment mainly relies on surgery, radiotherapy, and postoperative adjuvant endocrine therapy. However, approximately 30% of intermediate- to high-risk patients still face the risk of recurrence and metastasis. The MonarchE and NATALEE studies confirmed the effectiveness of CDK4/6 inhibitors in early-stage HR(+)/human epidermal growth factor receptor 2-negtive [HER-2(-)] breast cancer patients. In addition, studies on immunotherapy, such as the KEYNOTE-756 and CheckMate 7FL trials, explored the potential of PD-1 monoclonal antibodies combined with NAC in increasing the rate of pathological complete response (pCR) and reducing the risk of recurrence in high-risk patients. Standard treatment for advanced HR(+) breast cancer has evolved from single-agent endocrine therapy to combined therapy with CDK4/6 inhibitors, but resistance remains an issue. New drugs such as ADC drugs and PI3K/Akt/mTOR inhibitors are being explored to provide more treatment options. The TROPiCS-02 and TROPION-Breast01 studies validated the efficacy of TROP2-targeted ADC drugs in treating resistant HR(+)/HER-2(-) advanced breast cancer patients. Meanwhile, the INAVO 120 and Capitello-291 studies highlighted the potential of PI3K/Akt/mTOR signaling pathway inhibitors in improving treatment outcomes, especially for patients with PIK3CA mutations. In the treatment of early HER-2(+) breast cancer, the PHERGain study demonstrated the effectiveness of ¹⁸F-FDG PET/CT-based de-escalated chemotherapy adjusted according to pCR in neoadjuvant therapy for early HER-2(+) breast cancer. The APTneo study found that the addition of atezolizumab to chemotherapy had limited impact on increasing the pCR rate in neoadjuvant therapy, requiring further research to optimize efficacy and safety. Regarding advanced HER-2(+) breast cancer, the PHILA and HER2CLIMB-02 studies demonstrated the effectiveness of TKI drugs in first-line and second-line treatment. The DESTINY-Breast series of studies proved the efficacy and good safety profile of trastuzumab deruxtecan (T-DXd) in patients with HER-2(+) metastatic breast cancer across all age groups, with significant efficacy in patients with treated/stable and untreated/active brain metastases. Research on early triple-negative breast cancer (TNBC) focuses on the combination of immunotherapy and chemotherapy. The KEYNOTE-522 study showed that neoadjuvant therapy with chemotherapy plus pembrolizumab significantly increased pCR rates and event-free survival rates, and FDA and EMA have approved its use in the treatment of high-risk early-stage TNBC. However, the IMpassion030 study suggested that postoperative adjuvant immunotherapy may not be an effective option for all early-stage TNBC patients. For advanced TNBC, the KEYLYNK-009 study results showed that the combination of pembrolizumab and PARP inhibitors with chemotherapy did not significantly improve prognosis compared to pembrolizumab plus chemotherapy, but in patients with tBRCA mutations, this combination therapy significantly improved median progression-free survival (PFS), indicating its potential as first-line maintenance therapy for this patient population. The results of the BEGONIA study indicated that the combination therapy of Dato-DXd and durvalumab showed high response rates and longer PFS, potentially providing new treatment options for patients with advanced TNBC. In summary, research in the field of breast cancer treatment in 2023 has not only made breakthroughs in treatment methods but also innovated treatment concepts, bringing new hope to breast cancer patients.