title: A Prospective Validation Study of Bioimpedance with Volume Displacement in Early-Stage Breast Cancer Patients at Risk for Lymphedema.
abstract: BACKGROUND
  Although volume displacement (VD) is considered the gold standard for diagnosing breast cancer-related lymphedema, it is inconvenient. We compared bioimpedance (L-Dex) and VD measurements in a prospective cohort of breast cancer patients at risk for lymphedema.
  
  
  METHODS
  Between 2010 and 2014, a total of 223 breast cancer patients were enrolled. Following exclusions (n = 37), 186 received baseline VD and L-Dex; follow-up measurements were performed at 3-6 months intervals for 3 years. At each visit, patients fitted into one of three categories: normal (normal VD and L-Dex); abnormal L-Dex (L-Dex > 10 or increase in 10 from baseline and normal VD); or lymphedema (relative arm volume difference of >10 % by VD ± abnormal L-Dex). Change in L-Dex was plotted against change in VD; correlation was assessed using the Pearson correlation.
  
  
  RESULTS
  At a median follow-up of 18.2 months, 152 patients were normal, 25 had an abnormal L-Dex, and 9 developed lymphedema without a prior L-Dex abnormality. Of the 25 abnormal L-Dex patients, 4 progressed to lymphedema, for a total of 13 patients with lymphedema. Evaluating all time points, 186 patients had 829 follow-up measurements. Sensitivity and specificity of L-Dex compared with VD were 75 and 93 %, respectively. There was no correlation between change in VD and change in L-Dex at 3 months (r = 0.31) or 6 months (r = 0.21).
  
  
  CONCLUSIONS
  VD and bioimpedance demonstrated poor correlation with inconsistent overlap of measurements considered abnormal. Of patients with an abnormal L-Dex, few progressed to lymphedema; most patients with lymphedema did not have a prior L-Dex abnormality. Further studies are needed to understand the clinical significance of bioimpedance.
authors.affiliation: Breast Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA. barrioa@mskcc.org.|Department of Surgery, The Bryn Mawr Hospital, Bryn Mawr, PA, USA. barrioa@mskcc.org.
authors.forename: Andrea V
authors.initials: AV
authors.lastname: Barrio
authors.affiliation: Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
authors.forename: Anne
authors.initials: A
authors.lastname: Eaton
authors.affiliation: Department of Surgery, The Bryn Mawr Hospital, Bryn Mawr, PA, USA.
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Frazier
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000150:complications* / Q000473:pathology / Q000628:therapy; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000150:complications* / Q000473:pathology / Q000628:therapy; D003131:Combined Modality Therapy / Q000009:adverse effects*; D058266:Dielectric Spectroscopy / Q000379:methods*; D017097:Electric Impedance; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008209:Lymphedema / Q000175:diagnosis* / Q000209:etiology; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011379:Prognosis; D011446:Prospective Studies