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 to compare the composition of fluid compartments, could be used as a tool to diagnose lymphedema.
Lymphedema is a chronic accumulation of fluid and fibrous tissue that results from the disruption of lymphatic drainage. Secondary lymphedema of the upper extremity may develop following surgery for breast cancer; it has been reported in approximately 25% to 50% of women following mastectomy. Lymphedema can be a disfiguring condition. It results from lymphatic dysfunction or disruption and can be difficult to diagnose and manage accurately. At least 1 systematic review has found that early detection of secondary lymphedema in breast cancer improves outcomes. (1) One challenge is identifying the 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.
The detection of subclinical lymphedema (i.e., 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. The 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 subtle differences resulting from the initial accumulation of fluid.
Bioimpedance spectroscopy (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.
Bioimpedance has been proposed as a diagnostic test for this condition. In usual care, lymphedema is recognized clinically or via limb measurements. However, management via BIS has been proposed as a way to implement early treatment of subclinical lymphedema to potentially reduce its severity.
Devices that have been cleared for marketing by the U.S. Food and Drug Administration (FDA) through the 510(k) process to aid in the assessment of lymphedema are summarized in Table 1. FDA product code: OBH.
Table 1. FDA-Cleared BIS Devices for Lymphedema
Delfin Technologies (Stamford, CT)
To aid informing a clinical judgment of unilateral lymphedema in women
ImpediMed L-Dex™ U400
ImpediMed (Carlsbad, CA)
To aid clinical assessment of unilateral lymphedema of the arms in women
BIS: bioimpedance spectroscopy;
FDA: U.S. Food and Drug Administration;
This policy was created in 2010 and was based on a literature review was conducted using the MedLine database to relevant studies. The medical policy has been updated regularly with literature searches, most recently through August 17, 2018. The key literature is summarized below.
Medical policies assess whether a medical test is clinically useful. A useful test provides information to make a clinical management decision that improves the net health outcome. That is, the balance of benefits and harms is better when the test is used to manage the condition than when another test or no test is used to manage the condition.
The first step in assessing a medical test is to formulate the clinical context and purpose of the test. The test must be technically reliable, clinically valid, and clinically useful for that purpose. Medical policies assess the evidence on whether a test is clinically valid and clinically useful. Technical reliability is outside the scope of these reviews, and credible information on technical reliability is available from other sources.
Bioimpedance Spectroscopy (BIS) for Lymphedema
Clinical Context and Test Purpose
The purpose of using BIS in patients who have known or suspected lymphedema is to inform a diagnosis subclinical lymphedema to initiate treatment sooner than with other diagnostic methods.
The question addressed in this medical policy is: Does use of BIS devices detect lymphedema for individuals with known or suspected lymphedema?
The following PICOTS (patients, interventions, comparators, outcomes, timing, and setting) were used to select literature to inform this policy (see Table 2).
Table 2. PICOTS to Assess BIS
The relevant population of interest is individuals with known or suspected lymphedema.
The relevant intervention of interest is bioimpedance spectroscopy.
The relevant comparators of interest are volume displacement and circumferential measurement.
The general outcomes of interest are test accuracy and validity, symptoms, and quality of life.
The time frame for outcomes varies from months to years after onset of lymphedema symptoms.
During a physical exam conducted by a physician in an inpatient or outpatient setting.
PICOTS: patients, interventions, comparators, outcomes, timing, setting;
BIS: bioimpedance spectroscopy.
Simplifying Test Terms
There are 3 core characteristics for assessing a medical test. Whether imaging, laboratory, or other, all medical tests must be:
• Technically reliable,
• Clinically valid,
• Clinically useful.
Because different specialties may use different terms for the same concept, the core characteristics are highlighted. The core characteristics also apply to different uses of tests, such as diagnosis, prognosis, and monitoring treatment.
Diagnostic tests detect presence or absence of a condition. Surveillance and treatment monitoring are essentially diagnostic tests over a time frame. Surveillance to see whether a condition develops or progresses is a type of detection. Treatment monitoring is also a type of detection because the purpose is to see if treatment is associated with the disappearance, regression, or progression of the condition.
Prognostic tests predict the risk of developing a condition in the future. Tests to predict response to therapy are also prognostic. Response to therapy is a type of condition and can be either a beneficial response or adverse response. The term predictive test is often used to refer to response to therapy. To simplify terms, we use prognostic to refer both to predicting a future condition or to predicting a response to therapy.
Assessment of technical reliability focuses on specific tests and operators and requires review of unpublished and often proprietary information. Review of specific tests, operators, and unpublished data are outside the scope of this medical policy and alternative sources exist. This medical policy focuses on the clinical validity and clinical utility.
A test must detect the presence or absence of a condition, the risk of developing a condition in the future, or treatment response (beneficial or adverse).
A technology assessment on the diagnosis and treatment of secondary lymphedema, performed for the Agency for Healthcare Research and Quality (AHRQ), was published in 2010. (2) The AHRQ assessment identified 8 studies that reported the sensitivity and specificity of tests to diagnose secondary lymphedema. Reviewers noted that there is no true criterion standard to grade severity of lymphedema and that limb volume and circumference are used as de facto criterion standards. Two of the 8 selected studies evaluated bioimpedance devices. (3, 4) Overall, reviewers concluded that, due largely to heterogeneity among studies, the evidence did not permit conclusions on the optimal diagnostic test for detection of secondary lymphedema.
After the AHRQ review, several other studies have evaluated 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. (5) 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 follow-up volumetric measurements every 3 to 6 months for 3 years. At the last follow-up (median, 18.2 months), 152 (82%) patients had no lymphedema, 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. Also, 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%).
Blaney et al. (2015) reported on a prospective study with 126 women with stage I, II, or III unilateral breast cancer. (6) A total of 115 women underwent baseline assessment with a L-Dex and circumferential measurement (CM). The 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. Over 12 months, 31 participants were identified as having lymphedema by at least 1 of the assessment methods. Twenty-eight (90%) of 31 were identified by circumferential measurement and 11 (35%) by BIS. There was no statistically significant correlation between bioimpedance analysis and CM.
Section Summary: Clinically Valid
A 2010 AHRQ technology assessment identified few studies on bioimpedance analysis for diagnosing lymphedema. A few prospective studies, published after the AHRQ review, found suboptimal correlations between bioimpedance analysis and the reference standard. In the study that reported measures of diagnostic accuracy, bioimpedance analysis had a low sensitivity and specificity for predicting lymphedema development.
A test is clinically useful if the use of the results informs management decisions that improve the net health outcome of care. The net health outcome can be improved if patients receive correct therapy, or more effective therapy, or avoid unnecessary therapy, or avoid unnecessary testing.
The ideal study design is a randomized controlled trial (RCT) comparing health outcomes in patients managed with and without the use of bioimpedance devices. No RCTs were identified. However, a controlled observational study has compared clinical lymphedema rates in patients managed with and without bioimpedance analysis. This 2014 study, by Soran et al., involved prospective detection of subclinical lymphedema in 186 women with breast cancer managed with L-Dex or tape measurement of limb circumference. (7) Measurements were obtained at baseline and 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 the demographic and clinical characteristics of the preoperative and control groups and the preoperative and postoperative groups; they did not identify any statistically significant differences.
In the preoperative group, 28 (36%) of 72 women 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. Limitations of the study included a lack of an alternative method for detecting subclinical lymphedema in women in the control group so that they could receive treatment early; a lack of randomization to a treatment group; and incomplete data on pre- and postoperative measures of lymphedema except in a subset of the total population.
Laidley et al. (2016), in a retrospective cohort study conducted at 2 surgical practices, reported on the feasibility and outcomes for postoperative bioimpedance monitoring in women following axillary lymph node surgery for breast cancer. (8) Of 1113 patients, 326 patients who had undergone some form of axillary staging and preoperative and at least 2 postoperative bioimpedance measurements met the study’s eligibility criteria. The cumulative incidence of subclinical breast cancer-related lymphedema was 12.3%.
Section Summary: Clinically Useful
One prospective comparative study has 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 data on a substantial proportion of enrolled patients, 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 managed with bioimpedance analysis and who received treatment for subclinical lymphedema. An additional retrospective analysis suggested that postoperative bioimpedance monitoring is feasible, but provided limited information on its efficacy. 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 August 2018 did not identify any ongoing or unpublished trials that would likely influence this medical policy.
Practice Guidelines and Position Statements
National Lymphedema Network (NLN)
In December 2013, the NLN 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 [centimeter]) 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
For individuals who have known or suspected lymphedema who receive bioimpedance spectroscopy, the evidence 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 have found a poor correlation between bioimpedance analysis and the reference standard (volume displacement or circumferential measurement). There are no randomized controlled trials 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 included its retrospective design, lack of randomization or blinding, and lack of a systematic method for detecting early or subclinical lymphedema in the control group. An additional retrospective analysis suggested that postoperative bioimpedance monitoring is feasible, but provides limited information about its efficacy. The evidence is insufficient to determine the effects of the technology on health outcomes.
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1. Shah C, Arthur DW, Wazer D, et al. The impact of early detection and intervention of breast cancer-related lymphedema: a systematic review. Cancer Med. Jun 2016; 5(6):1154-62. PMID 26993371
2. 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).
3. 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
4. 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
5. 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
6. 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
7. 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
8. Laidley A, Anglin B. The impact of L-Dex((R)) Measurements in assessing breast cancer-related lymphedema as part of routine clinical practice. Front Oncol. Sep 2016; 6:192. PMID 27656420
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; reaffirmed 2018 August 17).
10. Bioimpedance Devices for Detection of Lymphedema. Chicago, Illinois: Blue Cross Blue Shield Association Medical Policy Reference Manual (January 2018) Medicine 2.01.82.
|10/1/2018||Document updated with literature review. Coverage unchanged. References 1 and 8 added; several references removed.|
|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.)|
|Title:||Effective Date:||End Date:|
|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|