Ultrasound: Assessment of breast dermal thickness: Reliability, responsiveness to change, and relationship to patient‐reported outcomes

BACKGROUND: The current study assessed the level of reliability of ultrasound to assess dermal thickness, a clinical feature of breast lymphedema. Additionally, the relationship of dermal thickness to patient‐reported outcomes was investigated. METHODS: Women (n = 82) with unilateral breast edema secondary to treatment of breast cancer were randomized to an exercise or control group. Ultrasound measurements of the unaffected and affected breasts were taken at baseline and 12 weeks later at 3–4 cm superior, medial, inferior, and lateral to the nipple. Additionally, women completed breast‐related questions from the European Organization Research and Treatment Committee Quality of Life breast cancer module (EORTC‐BR23) and Lymphedema Symptom Intensity and Distress Questionnaire (LSIDS). Reliability of ultrasound measurements was determined on the unaffected breast. RESULTS: Intraclass correlation coefficients (2,1) ranged from 0.66 (95% CI: 0.52–0.77) for the lateral location to 0.84 (0.77–0.90) for the superior location. Percent close agreement (80%) on the unaffected breast ranged from 0.20 to 0.27 mm compared to 0.57 to 0.93 mm on the affected breast. The standard error of measurement (%) on the unaffected breast varied from 9% to 13% with smallest real difference 0.34–0.41 mm. Dermal thickness of the affected breast was not‐to‐poorly associated with EORTC BR23 and LSIDS scores. CONCLUSION: Reliability of dermal thickness measurements of the breast was excellent for the superior, medial, and inferior locations, and fair to good for the lateral location. However, these measurements were not related to the symptom's women perceive and measured with the EORTC BR23 or LSIDS.