A prospective study of L-Dex values in breast cancer patients pretreatment and through 12 months postoperatively

Background: Data regarding pretreatment, bioimpedance spectroscopy (BIS) L-Dex^® values for patients newly diagnosed with breast cancer, and longitudinal data 12 months postoperatively are lacking. This study describes L-Dex values at the time of breast cancer diagnosis and maximum L-Dex change within 12 months of surgery. Methods and Results: Patients were enrolled in a parent, clinical trial that compares the effectiveness of BIS for early detection of breast cancer-related lymphedema to tape measurement. A total of 280 women with a pretreatment and at least one postoperative L-Dex measurement (within 12 months of surgery) were included. Pretreatment L-Dex readings were compared with population norms and maximum L-Dex changes within 12 months were examined. An L-Dex U400 device was used to obtain BIS measurements. The documented normative mean value using this device is 0.00, which is at the 49th percentile for this sample. Approximately 6% of patients had a pretreatment L-Dex value of ≥7.0; 1.8% had an L-Dex value ≥10.0. For 12 months, 17.1% (n = 48) of patients had a maximum change in L-Dex value from pretreatment of ≥7.0 L-Dex units, suggestive of clinical lymphedema. Conclusions: At the time of breast cancer diagnosis, L-Dex values are similar to normative values. Identified maximum changes in L-Dex values 12 months postoperatively suggest that frequent L-Dex measurements during that time frame are of potential clinical benefit. Our findings are consistent with research supporting an L-Dex value of ≥7 as indicative of clinical lymphedema with subclinical lymphedema logically occurring at somewhat lower likely, near ≥6.5.