© 2020 P.Ziti and Co. All rights reserved.Objective: The diagnosis, treatment, and management of the breast cancer (BC) require a multidisciplinary approach. In newly diagnosed BC, fluorine-18-fluorodeoxyglucose positron emission tomography (18F-FDG PET) can detect extra-axillary regional nodal and distant lesions. Subjects and Methods: Between 2010 and 2015, this study included 101 patients with early-stage BC who were examined with 18F-FDG PET before surgery. Patients were divided into two groups: Group 1 consisted of patients with suspected 18F-FDG uptake and Group 2 with the remaining 18F-FDG-negative patients. Differences between these groups were tested using the Pearson chi-square test, Fisher's exact test, Mann Whitney-U test, independent t-test and ROC analysis. They could be followed-up after 2015 for 5 years. All patients were then rediscussed either neoadjuvant therapy or surgery in the oncology board in 2020 with changing neoadjuvant criteria and oncoplastic surgery techniques. Results: Fluorine-18-FDG PET was found to have a sensitivity of 77.8% and a specificity of 90.8% in detecting axillary lymph node metastasis. During the minimum 5-year follow-up, one patient had bone metastasis, 2 patients had a local recurrence, and 3 patients had metastatic lymph nodes in the axilla. In the re-evaluation of the same patients over 5 years, the decrease in mastectomy decision was remarkable (P-value 0.01). Conclusion: We observed that we could not achieve significant difference in 5-year metastasis/recurrence between the groups. Moreover, due to F-FDG PET high false positivity, it significantly extended the time to surgery (P-value 0.01). In early-stage BC, 18F-FDG PET demonstrated better performance in axillary lymph nodes metastases detection in comparison with other diagnostic imaging methods, even if SLNB remains the gold standard technique.