Background: Breast cancer (BC) poses a significant health concern for females, often resulting in complications such as lymphedema due to treatment effects. Objectives: This study examines the link between lymphedema and the number of removed negative axillary lymph nodes (LNs) after sentinel lymph node biopsy (SLNB) in BC patients. Methods: A prospective study from 20l6 to 20l9 included l50 eligible women out of l 600 BC patients who underwent axillary sentinel node biopsy (SNB). The prognostic value of isolated negative nodes and BMI in predicting lymphedema post-SLNB was analyzed. Results: Among 950 women receiving radiotherapy, 4% developed lymphedema. Notably, patients with lymphedema were younger (average age 53.34 years). BMI didn't differ significantly, but the number of removed sentinel LN-negatives was crucial. Patients with 4-5 nodes removed had an 89.47% likelihood, while those with 1-3 nodes had zero incidence. Conclusions: BC-related lymphedema significantly impacts patient well-being. Our study establishes a direct correlation between the number of removed negative LNs and the severity of edema, emphasizing the need for further research.