AIM: To evaluate preoperative assessment clinical tools forsecondary upper extremity lymphedema surgical candidates. METHODS: A prospective cohort study performed at a tertiary cancer center secondary lymphedema outpatient clinic. Lymphedema evaluation included limb volume measurements, bioimpedance, indocyanine green lymphography, lymphoscintigraphy, magnetic resonance angiography (MRA), lymphedema life impact scale, and upper limb lymphedema 27 (ULL-27) questionnaires. RESULTS: A total of 118 patients were evaluated. Limb circumference difference underestimated lymphedema diagnosis compared to limb volume excess. Bioimpedance (L-Dex) scores highly correlated with limb volume excess (r2 = 0.714; P < 0.001). L-Dex scores were highly sensitive and had a high positive predictive value for diagnosing lymphedema in patients with a volume excess of 10% or more. Indocyanine green was highly sensitive in identifying lymphedema. Lymphoscintigraphy had an overall low sensitivity and specificity for the diagnosis of lymphedema. MRA was highly sensitive in diagnosing lymphedema and adipose hypertrophy as well as useful in identifying axillary vein obstruction and occult metastasis. Patients with minimal limb volume difference still demonstrated significantly impaired quality of life. CONCLUSION: Preoperative assessment of lymphedema is complex and requires multimodal assessment. MRA, L-Dex, ICG, and PROMs are all valuable components of preoperative assessment. Lymphedema clinicians can use these tools findings accordingly to tailor an optimal surgical plan for each patient.