Routine Indocyanine Green-Guided Axillary Reverse Mapping Prevents Lymphedema Without Compromising Oncological Safety: 54-Month Follow-Up in a Middle-Income Setting

Axillary lymph node dissection (ALND) is associated with a high risk of lymphedema. We assessed whether routine indocyanine green (ICG)-guided axillary reverse mapping (ARM) reduces the incidence and severity of lymphedema after ALND, while maintaining long-term oncological safety, in a propensity-matched cohort. In this retrospective study conducted between 2019 and 2024, 121 women undergoing ALND for invasive breast cancer were divided into an ARM group (n=62, from 2022 onward) and a non-ARM group (n=59). Lymphedema was assessed by blinded nurses using the Frustum formula (≥10% and ≥5% inter-limb volume difference) and International Society of Lymphology (ISL) staging at 3, 6, 12, 24, 36, 48, and 60 months. Propensity score matching (1:1) was used to balance age, BMI, neoadjuvant therapy, stage, surgery type, surgeon, and pandemic period (standardized mean difference <0.08). Sensitivity analysis was performed using inverse probability of treatment weighting (IPTW). Oncological safety was evaluated through histopathology of ICG-positive nodes and recurrence monitoring over a median follow-up of 54 months (IQR 36–72). After matching, the 60-month lymphedema incidence (≥10% threshold) was 8.1% in the ARM group versus 39.0% in the non-ARM group (p<0.001), yielding an absolute risk reduction of 30.9% and a number needed to treat of 3.2. Severe lymphedema (ISL stages 2–3) occurred in 6.5% versus 30.5% (p<0.001). Lymphedema-free survival significantly favored the ARM group (log-rank p=0.0003). Adjusted Cox regression demonstrated an 82% lower risk (hazard ratio 0.18, 95% CI 0.07–0.45; p<0.001; concordance 0.78), with robustness confirmed by IPTW (hazard ratio 0.20, p<0.001). No recurrences were observed (0/121; upper 95% CI 2.5%) over 54 months, despite 59% of patients having stage III disease. Routine ICG-guided ARM was associated with an 82% reduction in clinically significant lymphedema and appears oncologically safe over 54 months—the longest follow-up reported in a middle-income setting. Prospective randomized trials are warranted.