Are We Underestimating Breast Cancer-Related Lymphedema? The Impact of Diagnostic Thresholds and Compression Therapy.

[BACKGROUND] Breast cancer-related lymphedema (BCRL) is commonly diagnosed using limb volume criteria; however, diagnostic thresholds vary and lack empirical validation. This variability may lead to underdiagnosis, particularly in patients using compression garments that can reduce limb size.

[OBJECTIVE] This study evaluated how different diagnostic criteria and compression therapy influence the reported incidence of BCRL.

[METHODS] A single-institution analysis was conducted on 165 female patients with breast cancer originally enrolled in a randomized controlled trial comparing axillary lymph node dissection with and without immediate lymphatic reconstruction from 2020 to 2025. Limb volumes were measured preoperatively and at 12, 18, and 24 months postoperatively. BCRL incidence was assessed using 5%, 10%, and 15% thresholds for relative volume change (RVC) and interlimb volume difference. The Upper Limb Lymphedema-27 (ULL-27) questionnaire evaluated symptoms. Compression use was evaluated to determine the effect on BCRL incidence.

[RESULTS] BCRL incidence varied by threshold, from 55.8% at 5% RVC to 12.1% at 15% RVC. ULL-27 scores indicated comparable symptom burdens between patients meeting volume-based diagnostic criteria and those wearing compression garments but not meeting volume criteria. Both groups had significantly worse physical domain scores than patients without volume changes or compression use (P < 0.001). Including compression users who did not meet volume criteria increased the incidence of BCRL across all thresholds (e.g., 23.6% to 41.8% at 10% RVC).

[CONCLUSIONS] BCRL incidence varied markedly by volume-based diagnostic thresholds, and inclusion of compression users significantly increased reported rates. Relying solely on volume thresholds may miss symptomatic patients. Integrating compression use and patient-reported outcomes can better identify clinically meaningful BCRL.