Evaluation of upper limb lymphoedema and diagnostic accuracy of bioimpedance spectroscopy. A comprehensive validation in a Brazilian population

Lymphoedema is a complication of breast cancer treatment. Its early diagnosis is related to a good prognosis for lymphoedema treatment. The bioimpedance spectroscopy (BIS) evaluates changes in extracellular fluid. The objective of our study was to evaluate the validity, agreement and accuracy of BIS in the diagnosis of breast cancer-related lymph-oedema in a Brazilian population. Methods: This is a prospective, cross-sectional study of a convenience sample of 462 women who underwent surgical treatment for breast cancer (mastectomy or breast-conserving treatment). The validity, agreement and accuracy were performed comparing BIS (lymphoedema index (L-DEX) ≥ 6.5 or 10) with volumetry by water displacement, which is the gold standard for evaluating lymphoedema. Receiver operating characteristic curve was performed. Additionally, other methods like perimetry and indirect volumetry of the upper limbs were compared with water displacement volumetry (direct volumetry)