Diagnostic Accuracy of Clinical Measures Considering Segmental Tissue Composition and Volume Changes of Breast Cancer-Related Lymphedema

Background: If we use only volumetry for measuring lymphedema, we could underdiagnose lymphedema with characteristics of biomechanical changes without definite volume change, especially in the medial forearm. Methods and Results: In total, 158 breast cancer patients participated in this study. Arm volume was measured by water displacement volumetry, and segmental volumes were calculated from circumferences by using the truncated cone method. Subcutaneous ultrasound echogenicities were assessed on the medial side of the upper arm and forearm of both arms and graded by subcutaneous echogenicity grade (SEG) and revised SEG (rSEG). The standards for diagnosing secondary lymphedema were according to the volume change and clinical stage. Sensitivity, specificity, receiver-operating characteristic (ROC) curve, and area under the curve (AUC) were used. Analysis of ROC curves yielded AUCs of 0.875-0.933 (p<0.001). Volume differences in each segment were significantly different among the grades by SEG. The highest AUC was found for volume difference (AUC=0.919, 95% confidence interval [CI]=0.860-0.978) in the upper arm near the elbow; however, in the medial forearm, the highest AUC was found for rSEG (AUC=0.948, 95% CI=0.923-0.965 in the proximal forearm; AUC=0.940, 95% CI=0.923-0.965 in the distal forearm). Conclusions: Our findings support the use of SEG by ultrasound in the assessment of lymphedema, especially in the medial region of the forearm. Subcutaneous ultrasound echogenicities may improve the accuracy of diagnosis of lymphedema in the forearm.