Medical Policies - Medicine
Bioimpedance Devices for Detection of Lymphedema
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Devices using bioimpedance (bioelectrical impedance spectroscopy) are considered experimental, investigational and/or unproven for use in the diagnosis, surveillance, or treatment of patients with lymphedema, including use in subclinical secondary lymphedema.
Secondary lymphedema may develop following surgery for breast cancer. Bioimpedance, which uses resistance to electrical current in comparing the composition of fluid compartments, could potentially be used as a tool to diagnose lymphedema, particularly for subclinical disease.
Secondary lymphedema of the upper extremity may develop following surgical treatment for breast cancer; it has been reported in approximately 25% to 50% of women following mastectomy. This can be a chronic, disfiguring condition. It results from lymphatic dysfunction or disruption and can be difficult to accurately diagnose and manage. One challenge is identifying the presence of clinically significant limb swelling through simple noninvasive methods. Many techniques have been used for documenting lymphedema including measuring differences in limb volume (volume displacement) and limb circumference. A number of newer techniques are being evaluated, including bioimpedance with use of bioimpedance spectroscopy (BIS) analysis, which uses resistance to electrical current to compare the composition of fluid compartments. BIS is based on the theory that the level of opposition to flow of electric current (impedance) through the body is inversely proportional to the volume of fluid in the tissue. In lymphedema, with the accumulation of excess interstitial fluid, tissue impedance decreases.
The detection of subclinical lymphedema, that is, the early detection of lymphedema before clinical symptoms become apparent, is another area of study. Detection of subclinical lymphedema (referred to as stage 0 lymphedema) is problematic. Subclinical disease may exist for months or years before overt edema is noted. This approach generally involves comparison of preoperative (i.e., baseline) with postoperative measurements, because existing differences between upper extremities (like the effects of a dominant extremity) may obscure early, subtle differences resulting from the initial accumulation of fluid. Bioimpedance has been proposed as a diagnostic test for this condition. Those who support this approach to diagnose subclinical disease believe that early treatment of subclinical lymphedema should result in less severe chronic disease.
In 2007, the ImpediMed L-Dex™ U400 was cleared for marketing by the U.S. Food and Drug Administration (FDA) through the 510(k) process as an aid in the clinical assessment of unilateral lymphedema of the arms in women. It is not intended to diagnose or predict lymphedema. The FDA product code: OBH.
This policy was created in 2010 based on a literature review was conducted using the MedLine database to relevant studies. The review has been updated regularly with literature searches, most recently through March 2016. The key literature is summarized below.
Assessment of a diagnostic technology typically focuses on 3 parameters: 1) technical performance; 2) diagnostic performance (sensitivity, specificity, and positive and negative predictive value) in appropriate populations of patients; and 3) demonstration that the diagnostic information can be used to improve patient outcomes (clinical utility). While in some cases, tests can be adequately evaluated using technical and diagnostic performance, when a test identifies a new or different group of patients with a disease, randomized controlled trials (RCTs) are needed to demonstrate impact of the test on the net health outcome.
Technical performance of a device is typically assessed with 2 types of studies; those that compare test measurements with a criterion standard and those that compare results taken with the same device on different occasions (test-retest). While there is no absolute criterion standard for diagnosis of lymphedema, the de facto criterion standards are limb volume and/or limb circumference. Studies that address technical performance of bioimpedance devices are described below.
A 2010 publication by Czerniec et al. reported on measurement of lymphedema in a small group of patients, 33 with lymphedema and 18 without. (1) The study objective was to determine the relation between physical methods of measuring lymphedema and self-reported swelling. Measurement techniques included self-report, bioimpedance spectroscopy (BIS), perometer, and the truncated cone method. The authors noted that the physical measurement tools were highly reliable with high concordance (0.89 to 0.99, respectively). In this study, self-report correlated moderately with physical measurements (0.65 to 0.71, respectively) and was moderately reliable. The authors concluded that lymphedema assessment methods are concordant and reliable but not interchangeable.
In a U.S.-based study published in 2007, Warren et al. evaluated 15 patients with upper- or lower-extremity secondary lymphedema documented by lymphoscintigraphy, along with 7 healthy controls using BIS analysis. (2) In addition, both the affected and the unaffected limbs in lymphedema patients were evaluated so patients also served as their own controls. According to BIS in the lymphedema patients, the average ratio of current flow of the affected limb to the unaffected limb (impedance ratio) was 0.9 (range, 0.67-1.01). In the control group, the average impedance ratio was 0.99 (range, 0.95-1.02). Lower impedance ratio values correlated with higher levels of accumulated fluid.
A technology assessment on the diagnosis and treatment of secondary lymphedema, performed under contract from Agency for Healthcare Research and Quality (AHRQ) by the McMaster University Evidence-based Practice Center, was released in May 2010. (3) The AHRQ assessment identified 8 studies that reported the sensitivity and specificity of tests to diagnose secondary lymphedema. The investigators noted that there is no true “gold standard” to grade severity of lymphedema and that limb volume and circumference are used as de facto criterion standards. Two of the 8 studies on diagnostic performance of devices to detect secondary lymphedema evaluated bioimpedance devices. (4, 5) Overall, the investigators concluded that, due largely to heterogeneity among studies, the evidence does not permit conclusions on the optimal diagnostic test for detection of secondary lymphedema.
Subsequent to the AHRQ review, several studies were published on the diagnostic performance of bioimpedance devices for detecting lymphedema. Prospective studies that compared bioelectrical impedance analysis to a reference standard are described next.
A 2015 study by Barrio et al. enrolled 223 women with newly diagnosed breast cancer and a plan for unilateral axillary surgery. (6) Thirty-seven patients were excluded due to ineligibility or withdrawal, leaving a sample size of 186. Prior to surgery, participants received baseline volumetric measurements with a bioimpedance device (L-Dex) and volume displacement (VD, the reference standard). Patients then had regular follow-up volumetric measurements every 3 to 6 months for 3 years. At the last follow-up (median, 18.2 months), 152 patients (82%) were normal, 21 (11%) had an abnormal L-Dex and no lymphedema by VD, 4 (2%) had an abnormal L-Dex and lymphedema by VD, and 9 (5%) had lymphedema without prior L-Dex abnormality. In an analysis including only patients with at least 6 months of follow-up, L-Dex had a sensitivity of 31% (4/13) and a specificity of 88% (129/147) for predicting subsequent lymphedema development. In addition, the correlation between changes in VD and changes in L-Dex results were in the low-to-moderate range at 3 months (r=0.31) and 6 months (r=0.21). However, at the time of lymphedema diagnosis, the L-Dex ratio was abnormal in 12 of 13 patients (diagnostic sensitivity, 92%).
Another 2015 prospective study from Blaney et al. included 126 women newly diagnosed with stages I-III unilateral breast cancer. (7) A total of 115 women underwent baseline assessment with a bioimpedance device (L-Dex) and circumferential measurement (CM). CM was used as the reference standard, although the authors noted the test is an imperfect criterion standard. Postsurgical follow-up assessments were planned every 3 months for a year. The number of women completing these assessments was 109 (95%) at 3 months, 89 (77%) at 6 months, 79 (69%) at 9 months, and 71 (62%) at 12 months. During the 12-month study, 31 participants were identified as having lymphedema by at least 1 of the assessment methods. Twenty-eight of 31 (90%) were identified by CM and 11 (35%) by bioimpedance analysis. There was no statistically significant correlation between bioimpedance analysis and CM.
Section Summary: Diagnostic Performance
An AHRQ technology assessment published in 2010 identified few studies on bioimpedance analysis for diagnosing lymphedema. A few prospective studies were published subsequent to the AHRQ review, and they tended to find suboptimal correlation between bioimpedance analysis and the reference standard. In the 1 study that reported measures of diagnostic accuracy, bioimpedance analysis had a low sensitivity and specificity for predicting lymphedema development.
The ideal study design is a randomized controlled trial (RCT) comparing health outcomes in patients who were managed with and without the use of bioimpedance devices. No RCTs were identified. However, there was 1 controlled observational study comparing clinical lymphedema rates in patients managed with and without bioimpedance analysis. The 2014 study, by Soran et al., involved prospective detection of subclinical lymphedema in 186 women with breast cancer who were managed with L-Dex or tape measurement of limb circumference. (8) Measurements were obtained at baseline and at 3- to 6-month intervals for 5 years. Subclinical lymphedema was defined as an L-Dex value outside the normal range or that increased at least 10 units from baseline. Patients diagnosed with subclinical lymphedema were treated with, e.g., short-term physical therapy, compression garments, and received education on exercise and limb elevation. A total of 180 women were included in the analysis. Seventy-two women had both preoperative and postoperative bioimpedance and tape measurements (preoperative group). Forty-four women had preoperative bioimpedance and tape measurements but only had tape measurements postoperatively (control group). The remaining 64 women had postoperative bioimpedance and tape measurements, but no preoperative measurements (no preoperative group). The authors compared demographic and clinical characteristics of the preoperative and control groups and of the preoperative and postoperative groups; they did not identify any statistically significant differences.
In the preoperative group, 28 of 72 women (36%) were diagnosed with subclinical lymphedema and referred for treatment; 2 women progressed to clinical lymphedema. In the control group, 16 women (36%) developed clinical lymphedema during follow-up. A limitation of the study is that there was no alternative method for detecting subclinical women in the control group so that they could receive treatment early. Moreover, the women were not randomized to a treatment group and complete information (pre- and postoperative measures of lymphedema) was available for only a subset of the total population.
Section Summary: Clinical Utility
One prospective comparative study was identified that compared rates of clinical lymphedema in women managed with and without bioimpedance analysis. This study had several limitations, including nonrandomized design, lack of blinding, lack of complete information on a substantial number of patients in the study, and lack of a systematic method for diagnosing lymphedema in the control group. The authors reported a significantly lower rate of clinical lymphedema in patients who were managed with bioimpedance analysis and who received treatment for subclinical lymphedema. Additional studies to confirm these findings are needed, especially RCTs and trials that include an alternative method for early or subclinical lymphedema detection.
Ongoing and Unpublished Clinical Trials
A search of ClinicalTrials.gov in December 2015 did not identify any ongoing or unpublished trials that would likely influence this review.
Practice Guidelines and Position Statements
National Lymphedema Network (LNL)
The NLN December 2013 stated the following regarding bilateral arm measurements using a standard reproducible consistent method for all patients at the time breast cancer is diagnosed and for each follow-up visit for comparison (9):
• “Measurements should be recorded in the patient record and easily accessible to health care providers.”
• “Patients should be given a record of their measurements, including method(s) used for sharing purposes in case of relocation or change in health care providers.”
• “Documentation in the medical record should include the type of measurement method used and criteria for determining lymphedema development. The same method of measurement should be used for future assessments to facilitate comparison.”
Furthermore, the NLN defined the following: “The objective measurements (e.g., an increase of 1 cm) in any of the circumference measurements compared to the contralateral limb warrants a follow-up visit in one month. A 2 cm change in any of the circumferential measurements or a 5% volume change in an at-risk limb as calculated by a circumferential formula or perometry in the absence of such a change in the contralateral limb or a BIS reading outside normal limits for equipment being used (e.g., L-Dex reading >10) warrant immediate referral for further evaluation by a professional trained in lymphedema assessment and management. Circumferential tape measurements are acceptable when made with a flexible, non-elastic Gulick II (or similar) tape measure. At minimum, six measurements are recommended: circumference at the mid-hand, wrist, elbow, upper arm just below the axilla, and at 10 cm distal to and proximal to the lateral epicondyle on both arms. Bioelectrical spectroscopy (BIS) or infrared perometry are suggested as alternative or adjunct methods to circumferential measurement. Specific protocols describing standard positions and measurements for these procedures should be in place.”
Summary of Evidence
The evidence for bioimpedance devices in individuals who have known or suspected lymphedema includes several prospective studies on diagnostic accuracy and a controlled observational study evaluating clinical utility. Relevant outcomes are test accuracy and validity, symptoms, and quality of life. Recent diagnostic accuracy studies found a poor correlation between bioimpedance analysis and the reference standard (VD or CM). There are no RCTs evaluating the clinical utility of bioimpedance devices in the management of patients with lymphedema or at high risk of developing lymphedema. The single prospective comparative study found a significantly lower rate of clinical lymphedema in patients managed with bioimpedance devices. Limitations of this study include the retrospective design, lack of randomized or blinding, and lack of a systematic method of detecting early or subclinical lymphedema in the control group. The evidence is insufficient to determine the effects of the technology on health outcomes.
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1. Czerniec SA, Ward LC, Refshauge KM, et al. Assessment of breast cancer-related arm lymphedema-comparison of physical measurement methods and self-report. Cancer Invest. Jan 2010; 28(1):54-62. PMID 19916749
2. Warren AG, Janz BA, Slavin SA, et al. The use of bioimpedance analysis to evaluate lymphedema. Ann Plast Surg. May 2007; 58(5):541-3. PMID17452840
3. Oremus M, Walker K, Dayes I, et al. Technology Assessment: Diagnosis and treatment of secondary lymphedema. 2010. Available at: <http://www.cms.gov> (accessed October 2013).
4. Cornish BH, Chapman M, Hirst C, et al. Early diagnosis of lymphedema using multiple frequency bioimpedance. Lymphology. Mar 2001; 34(1):2-11. PMID 11307661
5. Hayes S, Janda M, Cornish B, et al. Lymphedema secondary to breast cancer: how choice of measure influences diagnosis, prevalence, and identifiable risk factors. Lymphology. Mar 2008; 41(1):18-28. PMID 18581955
6. Barrio AV, Eaton A, Frazier TG. A prospective validation study of bioimpedance with volume displacement in early-stage breast cancer patients at risk for lymphedema. Ann Surg Oncol. Dec 2015; 22 Suppl 3:370-5. PMID 26085222
7. Blaney JM, McCollum G, Lorimer J, et al. Prospective surveillance of breast cancer-related lymphoedema in the first-year post-surgery: feasibility and comparison of screening measures. Support Care Cancer. Jun 2015; 23(6):1549-59. PMID 25398360
8. Soran A, Ozmen T, McGuire KP, et al. The importance of detection of subclinical lymphedema for the prevention of breast cancer-related clinical lymphedema after axillary lymph node dissection; a prospective observational study. Lymphat Res Biol. Dec 2014; 12(4):289-94. PMID 25495384
9. National Lymphedema Network – Screening and Measurement for Early Detection of Breast Cancer Related Lymphedema (December 2013). Position Statement from NLN Advisory Committee. Available at <http://www.lymphnet.org> (accessed on 2016 April 4).
10. Bioimpedance Devices for Detection of Lymphedema. Chicago, Illinois: Blue Cross Blue Shield Association Medical Policy Reference Manual (January 2016) Medicine 2.01.82.
|10/15/2017||Reviewed. No changes.|
|6/1/2016||Document updated with literature review. Coverage unchanged. Rationale significantly revised with updated References.|
|3/15/2015||Reviewed. No changes.|
|4/15/2014||Document updated with literature review. Coverage unchanged.|
|7/15/2010||New medical document. Devices using bioimpedance (bioelectrical impedance spectroscopy) are considered experimental, investigational and unproven for use in the diagnosis, surveillance, or treatment of patients with lymphedema, including use in subclinical secondary lymphedema. (Coverage is unchanged. This topic was previously addressed on MED202.018, Plethysmography.)|
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|Bioimpedance Devices for Detection and Management of Lymphedema||09-15-2021||04-14-2022|
|Bioimpedance Devices for Detection and Management of Lymphedema||08-15-2020||09-14-2021|
|Bioimpedance Devices for Detection of Lymphedema||10-15-2019||08-14-2020|
|Bioimpedance Devices for Detection of Lymphedema||10-01-2018||10-14-2019|
|Bioimpedance Devices for Detection of Lymphedema||10-15-2017||09-30-2018|
|Bioimpedance Devices for Detection of Lymphedema||06-01-2016||10-14-2017|
|Bioimpedance Devices for Detection of Lymphedema||03-15-2015||05-31-2016|
|Bioimpedance Devices for Detection of Lymphedema||04-15-2014||03-14-2015|
|Bioimpedance Devices for Detection of Lymphedema||08-01-2012||04-14-2014|
|Bioimpedance Devices for Detection of Lymphedema||07-15-2010||07-31-2012|