Recent advances and updated highlights in breast cancer pathologic diagnosis: a narrative review.

Background and objective: With the rapid development of breast cancer treatment, breast cancer pathologic diagnosis has faced many requirements and challenges. This article reviews and summarizes important results that will change the clinical practice of breast cancer in 2023 and 2024.

Methods: As of April 2024, a comprehensive literature search, compilation, and analysis were conducted across PubMed, Baidu Scholar, ClinicalTrials.gov, and relevant academic conferences.

Key content and findings: This article focused on invasive lobular carcinoma (ILC), phyllodes tumors, new advances in immunohistochemical (IHC) indexes, updated advances in neoadjuvant therapy for breast cancer, and advances in the study of human epidermal growth factor receptor 2 (HER2)-low breast cancer. ILC has unique molecular distribution and clinical characteristics, distinguishing it from the traditional molecular classification and clinical features of invasive ductal carcinoma. Understanding the accurate diagnosis, immune microenvironment, and genetic changes of phyllodes tumors holds pivotal importance in guiding clinical treatment. Pathologic evaluation after neoadjuvant therapy is essential for the treatment of breast cancer patients, but clear and uniform criteria are lacking. With the breakthrough of new antibody-drug conjugate drugs in the treatment of breast cancer patients with low HER2 expression, the pattern of traditional anti-HER2 treatment has changed, bringing targeted benefit opportunities for more breast cancer patients. At the same time, the dichotomy used for breast cancer HER2 detection and interpretation has also been broken, which puts forward more accurate requirements for pathological diagnosis. IHC results for HER2 low also exhibit variability and are influenced by various factors.

Conclusions: Breast cancer treatment and pathology have made significant progress in 2023 and 2024. This will help ensure more accurate diagnoses and provide long-term treatment benefits for patients.