Conference Coverage

Bioimpedance spectroscopy may better identify lymphedema progression



Bioimpedance spectroscopy may better identify lymphedema progression in women at risk for breast cancer–related lymphedema over the traditionally used method of monitoring arm circumference with a tape measure, according to results from an interim analysis of the PREVENT trial presented in a recent webcast from the annual meeting of the American Society of Breast Surgeons.

“Despite advances in breast-conserving surgery, improved radiation protocol, the advent of sentinel [node] biopsies and recent improvement in chemotherapy regimens, breast cancer–related lymphedema ... remains a major source of morbidity and concern in this patient population,” Sheila Ridner, PhD, RN, FAAN, professor of nursing at the Vanderbilt University School of Nursing in Nashville, Tenn., said in her presentation. “Because it is thought that early identification of swelling in the limbs coupled with a compression intervention may reduce the risk of patients developing full-blown clinical lymphedema, clinicians are proposing to use a prospective surveillance model to follow breast cancer survivors post surgery in order to assess limbs in a routine fashion and perhaps instigate preventative mechanisms early.”

The larger randomized controlled Prevention of Lymphedema Following Locoregional Treatment for Breast Cancer (PREVENT) trial enrolled 1,201 patients, and 200 patients overall have completed the full protocol. The researchers plan to follow patients for 3 years after surgery. In this interim analysis, Dr. Ridner and colleagues analyzed data from 508 patients at eight sites in the United States and four sites in Sydney who had stage I through stage III or ductal carcinoma in situ (DCIS) breast cancer and underwent mastectomy, taxane-based chemotherapy, or an axillary treatment such as axillary radiation, axillary lymph node dissection, or sentinel lymph nose biopsy with more than 6 nodes.

The patients were randomized to be measured using either traditional tape measurement or bioimpedance spectroscopy (BIS). Patients were moved to a prevention intervention if there was a change in baseline volume of 5% or greater but less than 10% in the tape measure group and change from baseline L-Dex measurement of 6.5 or greater in the BIS group, which consisted of wearing an arm compression sleeve and chest gauntlet for 12 hours a day over 4 weeks. After surgery, the patients were followed up at 3 months, 6 months, 12 months, 18 months, and 24 months, with optional follow-up visits at 15 months and 21 months. Progression to full lymphedema was defined as a 10% or greater change in pretreatment baseline measurements in the tape measure group.

Of the 508 patients analyzed, 10 patients had already progressed to full lymphedema, leaving 498 patients available for the interim analysis. There were 68 patients in the tape measure group (28.5%) and 41 patients in the BIS group (15.8%) who received the prevention intervention, and 10 patients in the tape measure group (14.7%) and 2 patients in the BIS group (4.9%) eventually progressed to full lymphedema. In the BIS group, there was a 10% absolute reduction and 67% relative reduction in lymphedema progression, compared with the tape measure group.

“We believe that the 10% absolute reduction is clinically significant for this patient population,” said Dr. Ridner. “We also believe that our interim results may support the concept of posttreatment surveillance using BIS for early detection of subclinical lymphedema coupled with early intervention as our preliminary data suggest this does have clinical advantages to the patient.”

The study was funded by ImpediMed. Dr. Ridner reports being the principal investigator for ImpediMed and Tactile Medical through work agreements contracted between the companies and her institution.

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