Breast cancer in women aged 80 years and older accounts for about 12% of cases, but its management is challenging due to the population's heterogeneity and the lack of relevant evidence-based guidelines. Treatment decisions must consider biological age, comorbidities, life expectancy, therapy-related toxicities, and tumor biology. This study evaluates the clinical outcomes of elderly breast cancer patients treated with a multidisciplinary approach, including oncologists, surgeons, and geriatric specialists. A retrospective analysis of breast cancer patients aged ≥80 years treated at Fondazione Policlinico Universitario Agostino Gemelli IRCCS in Rome, Italy, from January 2016 to December 2020 was conducted. The study reviewed clinicopathological data, surgery, adjuvant therapies, and clinical outcomes. Treatment decisions were guided by multidisciplinary evaluations, including onco-geriatric assessments (GA) and guided treatment decisions. Primary outcomes included overall survival (OS), disease-free survival (DFS), and cancer-specific survival (CSS). Surgical and treatment-related complications were also documented. A total of 238 patients aged ≥80 years were included in the study. Of these, 203 (85.3%) underwent breast-conserving surgery, while 35 (14.7%) underwent mastectomy. Axillary surgery was performed in 129 (54%) cases. Regarding adjuvant treatments, 93 (39.1%) patients received radiotherapy, and 101 (42.4%) received endocrine therapy alone. Chemotherapy was administered to six high-risk patients following GA, with no reported toxicities. Over a median follow-up of 42.3 months, the study reported one local recurrence (0.5%), one regional node recurrence (0.5%), and 19 cases of distant metastases (9%). A total of 19 patients (9%) died due to breast cancer. The overall complication rate was low, with 10% experiencing wound dehiscence, hematoma, lymphedema, or similar issues. Five-year survival outcomes were OS 73.3%, DFS 66.6%, and CSS 88.5%. This study highlights that a multidisciplinary approach to breast cancer management in patients aged ≥80 years yields favorable clinical outcomes with low recurrence, metastasis, and complication rates. The personalized treatment strategies, guided by onco-geriatric assessments, balance survival benefits with quality of life while minimizing risks of overtreatment or undertreatment. These findings emphasize the importance of individualized care in this complex patient population and offer valuable insights for optimizing management strategies as the elderly demographic continues to grow.