The goal of this observational study is to assess survival outcomes and treatment-related toxicity in patients with early-stage breast cancer receiving adjuvant therapies, using high-quality individual patient data pooled from seven clinical studies conducted by the Hellenic Cooperative Oncology Group (HeCOG), including 3 phase III trials and 4 observational studies. This study aims to assess long-term disease-free survival (DFS) and overall survival (OS), as well as the toxicity patterns associated with dose-dense sequential chemotherapy in intermediate or high-rsk patients.