(ChemotherapyAdvisor) – Using bioelectrical impedance analysis (BIA) to assess lymphedema using a diagnostic cut-off of L-Dex ratio >7.1 will still miss 20% of true lymphedema cases, underscoring the need for clinicians to integrate other assessment methods to ensure accurate diagnosis, reported Mei R. Fu, PhD, MS, MA, RN, APRN-BC, assistant professor of nursing at New York University, New York, during the 2013 Breast Cancer Symposium held in San Francisco, CA.
These methods may include self-report, clinical observations, or perometry, Dr. Fu added, who emphasized that lymphedema is a progressive and debilitating condition in survivors of breast cancer, with early treatment usually leading to better clinical outcomes.
“Despite its value in assessing lymphedema, the use of BIA in clinical settings is still very limited,” Dr. Fu noted. “In part, this may be due to anecdotal complaints from clinicians about BIA’s ability to identify [a] true case of lymphedema in the clinical settings using L-Dex ratio >+10 as the cut-off point for lymphedema diagnosis.”
Other drawbacks include lack of large clinical data to support the reliability, sensitivity, and specificity of using the L-Dex ratio.
Therefore, Dr. Fu and colleagues examined the reliability, sensitivity, and specificity of BIA, which directly measures lymph fluid changes, in 250 women, including healthy female adults, survivors of breast cancer with lymphedema, and those at risk for lymphedema.
They found the BIA ratio (as indicated by L-Dex ratio) to be highly reliable among healthy women (intraclass correlation coefficient [ICC], 0.99; 95% CI: 0.99-0.99), survivors at-risk for lymphedema (ICC, 0.99; 95% CI: 0.99-0.99), and all women (ICC, 0.85; 95% CI: 0.81-0.87).
Results showed reliability to be acceptable for survivors with lymphedema (ICC, 0.69; 95% CI: 0.54-0.80). At a diagnostic cutoff of >+7.1, the L-Dex ratio discriminated between at-risk survivors of breast cancer and those with lymphedema with 80% sensitivity and 90% specificity (area under the curve, 0.86).
Despite its costs, BIA may therefore have a role in clinical practice to add confidence in the diagnosis of arm lymphedema among survivors of breast cancer, Dr. Fu concluded.