Young female early breast cancer (≤ 40 years) treatment presents unique challenges due to its aggressive features. Using data from the Taiwan Cancer Registry (2007-2017), this study investigated its clinical characteristics, treatment patterns, and prognostic factors. The proportion of young female breast cancer declined from 12% to 8% during the study period. Triple-negative (TN) breast cancer was more prevalent in younger patients, while hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative subtypes increased with age. Stages II and III were observed more frequently in older patients, whereas extremely young patients (20-29 years) exhibited compromised overall and recurrence-free survival. Subtype analysis revealed worse outcomes for TN and hormone receptor-negative/human epidermal growth factor receptor 2-positive (HER2+) cases. Treatment patterns showed that targeted therapy was more commonly administered to younger patients with HER2+, while endocrine therapy was used less frequently for HR+ cases, reflecting tolerability and treatment compliance challenges. Future research should focus on optimizing therapeutic strategies and addressing long-term survivorship to enhance care for young women with breast cancer.