BACKGROUND: Immediate lymphatic reconstruction (ILR) has emerged as an effective intervention to reduce breast cancer-related lymphedema, which affects 2-30% of patients who undergo axillary lymph node dissection (ALND). Our previous research validated ILR's effectiveness over 14 months, but the duration was short and warranted further study. This study provides long-term evidence of its benefits in a well-defined patient cohort. METHOD: This retrospective cohort study included unilateral breast cancer patients who underwent ALND between November 2019 and February 2021 with ≥ 24 months of follow-up. Patients were grouped by whether ILR was attempted intraoperatively. Exclusion criteria were recurrence, prophylactic mastectomy, and pre-existing lymphedema. The primary outcome was lymphedema incidence at ≥ 24 months; the secondary was lymphedema-free survival. Outcomes were evaluated using Cox regression models. RESULTS: Among 73 patients, we analyzed ALND patients divided into a control group (n = 57, defined as no-try or failure) and an ILR group (n = 16). The pooled median follow-up was 37 months. (range, 26~47 months). Among the ILR group, 13 underwent end-to-end anastomosis and 3 end-to-side. Postoperative lymphedema was higher in the control group (24.6%) compared to the ILR group (6.3%). Multivariate Cox regression analysis showed a significantly lower hazard ratio for the ILR group (HR: 0.117, 95% CI: 0.014-0.965), emphasizing ILR's effectiveness in reducing lymphedema risk post-ALND. Additionally, survival plots illustrating lymphedema-free survival showed a significant difference. CONCLUSION: Our study emphasizes ILR's efficacy over extended follow-up. The ILR group exhibited a lower rate of postoperative lymphedema, supporting ILR as an effective preventive measure against Breast Cancer-Related Lymphedema (BCRL) following ALND.