Responsiveness of Ultrasonographic Subcutaneous Tissue Parameters to Complex Decongestive Therapy in Breast...

Ultrasonographic subcutaneous tissue parameters have previously been used as outcome measures in the evaluation of breast cancer-related lymphedema (BCRL). However, their ability to detect clinically meaningful changes-referred to as responsiveness-has not yet been examined. This study aimed to investigate the responsiveness of ultrasonographic subcutaneous tissue thickness measurements, subcutaneous echogenicity (SEG), and subcutaneous echo-free space (SEFS) changes.

Forty patients with International Society of Lymphology Stage 2-3 unilateral lymphedema underwent phase 1 complex decongestive therapy three times weekly for 4 weeks. Ultrasonographic subcutaneous tissue thickness, SEG, and SEFS, alongside circumferential measurements, limb volume, and visual analog scale scores for pain, heaviness, and tightness, were evaluated pre- and posttreatment. Significant symptomatic improvement was observed (p < 0.0001). Edema volume and percentage decreased significantly (p = 0.012 and p = 0.006). Subcutaneous tissue thickness significantly decreased at the upper arm medial, medial epicondyle, and wrist (p < 0.02), demonstrating the highest responsiveness (effect size = 1.74). In contrast, changes in SEG and SEFS were statistically significant only at limited sites and showed small to negligible responsiveness overall; however, SEFS showed comparatively higher responsiveness at the wrist, the site with the greatest baseline free-fluid accumulation. Circumferential and volumetric measures showed low responsiveness.

Subcutaneous tissue thickness was the most sensitive ultrasonographic marker in BCRL, followed by symptom scores. SEG and SEFS showed limited overall responsiveness, although SEFS remained meaningful at the wrist. Edema volume and percentage showed greater responsiveness than overall limb volume and circumferential measurements. Integrating subcutaneous thickness with edema-specific and symptom assessment may enhance monitoring of therapeutic outcomes.