A Bioimpedance Spectroscopy-Based Method for Diagnosis of Lower-Limb Lymphedema.

Background: This study aimed at testing whether arm-to-leg ratios of extracellular water (ECW) and ECW normalized to intracellular water (ICW), measured by bioimpedance spectroscopy (BIS), can accurately detect bilateral, lower-limb lymphedema, and whether accounting for sex, age, and body mass index (BMI) improves the diagnostic performance of cut-offs. Methods and Results: We conducted a dual-approach, case-control study consisting of cases of bilateral, lower-limb lymphedema and healthy controls who self-reported absence of lymphedema. The diagnostic performance using normative data-derived cut-offs (i.e., mean + 0.5 standard deviation [SD] to mean + 3 SD; n = 136, 66% controls) and receiver operating characteristic (ROC) curve-derived cut-offs (n = 746, 94% controls) was assessed. The impact of sex, age, and BMI was investigated by comparing stratified and nonstratified normative data-derived cut-offs, and ROC curves generated from adjusted and unadjusted logistic regression models. Arm-to-leg ratios of ECW between mean + 0.5 SD and mean + 1 SD showed fair to good sensitivity (0.73-0.84) and poor to good specificity (0.64 to 0.84). Arm-to-leg ratios of ECW/ICW failed to detect lymphedema (sensitivity <0.5). Stratification by sex, or by sex and age, yielded similar results to nonstratified cut-offs. Cut-offs derived from adjusted ROC curves showed both good sensitivity (0.83-0.89) and specificity (0.8-0.84). Conclusion: These findings represent new BIS criteria for diagnosing lower-limb lymphedema that do not rely on comparison to baseline measures or the presence of a nonaffected, contralateral limb.

Normative Interlimb Impedance Ratios: Implications for Early Diagnosis of Uni- and Bilateral, Upper and Lower Limb Lymphedema.

Background: Bioimpedance spectroscopy detects unilateral lymphedema if the ratio of extracellular fluid (ECF) between arms or between legs is outside three standard deviations (SDs) of the normative mean. Detection of bilateral lymphedema, common after bilateral breast or gynecological cancer, is complicated by the unavailability of an unaffected contralateral limb. The objectives of this work were to (1) present normative values for interarm, interleg, and arm-to-leg impedance ratios of ECF and ECF normalized to intracellular fluid (ECF/ICF); (2) evaluate the influence of sex, age, and body mass index on ratios; and (3) describe the normal change in ratios within healthy individuals over time. Methods: Data from five studies were combined to generate a normative data set (n = 808) from which mean and SD were calculated for interarm, interleg, and arm-to-leg ratios of ECF and ECF/ICF. The influence of sex, age, and body mass index was evaluated using multiple linear regression, and normative change was calculated for participants with repeated measures by subtracting their lowest ratio from their highest ratio. Results: Mean (SD) interarm, interleg, dominant arm-to-leg, and nondominant arm-to-leg ratios were 0.987 (0.067), 1.005 (0.072), 1.129 (0.160), and 1.165 (0.174) for ECF ratios; and 0.957 (0.188), 1.024 (0.183), 1.194 (0.453), and 1.117 (0.367) for ECF/ICF ratios, respectively. Arm-to-leg ratios were significantly affected by sex, age, and body mass index. Mean normative change ranged from 7.2% to 14.7% for ECF ratios and from 14.7% to 67.1% for ECF/ICF ratios. Conclusion: These findings provide the necessary platform for extending bioimpedance-based screening beyond unilateral lymphedema.

Lymphedema following gynecological cancer: Results from a prospective, longitudinal cohort study on prevalence, incidence and risk factors.

OBJECTIVE: Cancer-related lymphedema is a debilitating condition that adversely influences function, health and quality of life. The purpose of this study was to assess the prevalence, incidence, and risk factors of lower-limb lymphedema pre- through to 24months post-surgery for gynecological cancer. METHODS: A clinic-based sample of women (n=408) with gynecological cancer participated in a prospective, longitudinal study (2008-2011) using self-reported measures (swelling in one or both legs) and objectively measured lymphedema (bioimpedance spectroscopy) at baseline (pre-surgery), six weeks-three months, 6-12months, and 15-24months post-surgery. RESULTS: At pre-surgery, 15% of women self-reported lymphedema and 27% had measurable evidence of lymphedema. By 24months post-surgery, incidence of new self-reported or measured lymphedema was 45% and 37%, respectively. Three-quarters of these new cases presented by 12-months post-treatment. While lymphedema was transient for some women, 60% had persistent lymphedema. More extensive lymph node dissection, receipt of chemotherapy and radiation therapy, increasing body mass index, insufficient levels of physical activity, diagnosis of vulvar/vaginal cancer and presence of pre-treatment lymphedema were identified as potential risk factors (p<0.05). CONCLUSION: Findings support the need for integration of pre-surgical assessment, and prospective, post-treatment surveillance of lymphedema into gynecological cancer care. Future research exploring the role of maintaining healthy body weight, regular physical activity and education about early detection of lymphedema to improve gynecological cancer survivorship is warranted.

Acute Inflammatory Response to Low-, Moderate-, and High-Load Resistance Exercise in Women With Breast Cancer-Related Lymphedema.

Background Resistance exercise is emerging as a potential adjunct therapy to aid in the management of breast cancer-related lymphedema (BCRL). However, the mechanisms underlying the relationships between the acute and long-term benefits of resistance exercise on BCRL are not well understood. Purpose To examine the acute inflammatory response to upper-body resistance exercise in women with BCRL and to compare these effects between resistance exercises involving low, moderate, and high loads. The impact on lymphedema status and associated symptoms was also compared. Methods A total of 21 women, 62 ± 10 years old, with BCRL participated in the study. Participants completed low-load (15-20 repetition maximum [RM]), moderate-load (10-12 RM), and high-load (6-8 RM) exercise sessions consisting of 3 sets of 6 upper-body resistance exercises. Sessions were completed in a randomized order separated by a 7- to 10-day wash-out period. Venous blood samples were obtained to assess markers of exercise-induced muscle damage and inflammation. Lymphedema status was assessed using bioimpedance spectroscopy and arm circumferences, and associated symptoms were assessed using Visual Analogue Scales for pain, heaviness, and tightness. Measurements were conducted before and 24 hours after the exercise sessions. Results No significant changes in creatine kinase, C-reactive protein, interleukin-6, and tumor necrosis factor-α were observed following the 3 resistance exercise sessions. There were no significant changes in arm swelling or symptom severity scores across the 3 resistance exercise conditions. Conclusions The magnitude of acute exercise-induced inflammation following upper-body resistance exercise in women with BCRL does not vary between resistance exercise loads.

Bioimpedance in the assessment of unilateral lymphedema of a limb: the optimal frequency.

BACKGROUND: Bioimpedance techniques provide a reliable method of assessing unilateral lymphedema in a clinical setting. Bioimpedance devices are traditionally used to assess body composition at a current frequency of 50 kHz. However, these devices are not transferable to the assessment of lymphedema, as the sensitivity of measuring the impedance of extracellular fluid is frequency dependent. It has previously been shown that the best frequency to detect extracellular fluid is 0 kHz (or DC). However, measurement at this frequency is not possible in practice due to the high skin impedance at DC, and an estimate is usually determined from low frequency measurements. This study investigated the efficacy of various low frequency ranges for the detection of lymphedema. METHODS AND RESULTS: Limb impedance was measured at 256 frequencies between 3 kHz and 1000 kHz for a sample control population, arm lymphedema population, and leg lymphedema population. Limb impedance was measured using the ImpediMed SFB7 and ImpediMed L-Dex(®) U400 with equipotential electrode placement on the wrists and ankles. The contralateral limb impedance ratio for arms and legs was used to calculate a lymphedema index (L-Dex) at each measurement frequency. The standard deviation of the limb impedance ratio in a healthy control population has been shown to increase with frequency for both the arm and leg. Box and whisker plots of the spread of the control and lymphedema populations show that there exists good differentiation between the arm and leg L-Dex measured for lymphedema subjects and the arm and leg L-Dex measured for control subjects up to a frequency of about 30 kHz. CONCLUSIONS: It can be concluded that impedance measurements above a frequency of 30 kHz decrease sensitivity to extracellular fluid and are not reliable for early detection of lymphedema.

Lymphedema after breast cancer: incidence, risk factors, and effect on upper body function.

PURPOSE: Secondary lymphedema is associated with adverse physical and psychosocial consequences among women with breast cancer (BC). This article describes the prevalence and incidence of lymphedema between 6 and 18 months after BC treatment; personal, treatment, and behavioral correlates of lymphedema status; and the presence of other upper-body symptoms (UBS) and function (UBF). PATIENTS AND METHODS: A population-based sample of Australian women (n = 287) with recently diagnosed, invasive BC were evaluated on five occasions using bioimpedance spectroscopy. Lymphedema was diagnosed when the ratio of impedance values, comparing treated and untreated sides, was three standard deviations more than normative data. UBF was assessed using the validated Disability of the Arm, Shoulder, and Hand questionnaire. RESULTS: From 6 to 18 months after surgery, 33% (n = 62) of the sample were classified as having lymphedema; of these, 40% had long-term lymphedema. Although older age, more extensive surgery or axillary node dissection, and experiencing one or more treatment-related complication(s) or symptom(s) at baseline were associated with increased odds, lower socioeconomic status, having a partner, greater child care responsibilities, being treated on the dominant side, participation in regular activity, and having good UBF were associated with decreased odds of lymphedema. Not surprisingly, lymphedema leads to reduced UBF; however, BC survivors report high prevalences of other UBS (34% to 62%), irrespective of their lymphedema status. CONCLUSION: Lymphedema is a public health issue deserving greater attention. More systematic surveillance for earlier detection and the potential benefits of physical activity to prevent lymphedema and mitigate symptoms warrant further clinical integration and research.

Chemoprevention by alpha-santalol on UVB radiation-induced skin tumor development in mice.

Studies have shown the chemopreventive effects of alpha-santalol on chemically and UVB-induced skin cancer in mice. The objective of the present investigation was to find the lowest effective concentration of alpha-santalol for the chemopreventive effects on UVB-induced skin tumor development in mice and to determine antiperoxidant effect of alpha-santalol in order to elucidate its possible mechanism of action. Female SKH-1 mice were divided into different groups receiving either vehicle alone or different concentrations of alpha-santalol. Mice in all the groups were initiated and promoted with UVB radiation for skin tumor development. The promotion phase continued for 30 weeks. Skin tumors were counted once a week for 30 weeks. Lipid peroxidation was assayed in skin and liver microsomes by measuring malonaldehyde formed using thiobarbituric acid method. Topical administration of alpha-santalol reduced UVB-induced skin tumor development in a concentration-dependent manner. Application of alpha-santalol (5%) significantly (p < 0.05) delayed skin tumor development for 25 weeks and reduced tumor multiplicity. alpha-Santalol also inhibited in vitro lipid peroxidation in skin and liver microsomes. alpha-Santalol application prevents UVB-induced skin tumor development possibly by acting as an antiperoxidant.

Determination of Cole parameters in multiple frequency bioelectrical impedance analysis using only the measurement of impedances.

Conventional bioimpedance spectrometers measure resistance and reactance over a range of frequencies and, by application of a mathematical model for an equivalent circuit (the Cole model), estimate resistance at zero and infinite frequencies. Fitting of the experimental data to the model is accomplished by iterative, nonlinear curve fitting. An alternative fitting method is described that uses only the magnitude of the measured impedances at four selected frequencies. The two methods showed excellent agreement when compared using data obtained both from measurements of equivalent circuits and of humans. These results suggest that operational equivalence to a technically complex, frequency-scanning, phase-sensitive BIS analyser could be achieved from a simple four-frequency, impedance-only analyser.

Comparison of methods to diagnose lymphoedema among breast cancer survivors: 6-month follow-up.

One of the more problematic and dreaded complications of breast cancer is lymphoedema. Our objective was to determine the prevalence of lymphoedema 6-months following breast cancer treatment and to examine potential risk factors among a population-based sample of women residing in South-East Queensland (n = 176). Women were defined as having lymphoedema if the difference between the sum of arm circumferences (SOAC) of the treated and untreated sides was >5 cm (prevalence = 11.9%) or >10% (prevalence = 0.6%), their multi- frequency bioelectrical impedance (MFBIA) score was > or =3 standard deviations above the reference impedance score (prevalence = 11.4%), or they reported 'yes' when asked if arm swelling had been present in the previous 6 months (prevalence = 27.8%). Of those with lymphoedema defined by MFBIA, only 35% were detected using the SOAC method (difference > 5 cm), while 65% were identified via the self-report method (i.e., respective sensitivities). Specificities for SOAC (difference > 5 cm) and self-report were 88.5% and 76.9%, respectively. When examining associations between presence of lymphoedema and a range of characteristics, findings also varied depending on the method used to assess lymphoedema. Nevertheless, one of the more novel and significant findings was that being treated on the non-dominant, compared to dominant, side was associated with an 80% increased risk of having lymphoedema (MFBIA). Our work raises questions about the use of circumferences as the choice of measurement for lymphoedema in both research and clinical settings, and assesses MFBIA as a potential alternative.

A new technique for the quantification of peripheral edema with application in both unilateral and bilateral cases.

Current noninvasive techniques for the routine and frequent quantification of peripheral lymphedema in patients are total limb volume measurement (by water immersion or by circumferential measurements) and bioelectrical impedance analysis (BIA). However both of these techniques require standardizing the measurement using a contralateral measurement from the unaffected limb. Hence these techniques are essentially restricted to unilateral lymphedema. This paper describes the results from a preliminary study to investigate an alternative approach to the analysis of the data from multiple frequency BIA to produce an index of lymphedema without the need for normalization to another body segment. Twenty patients receiving surgical treatment for breast cancer were monitored prior to surgery and again after diagnosis with unilateral lymphedema. The data recorded were total limb volume, by circumferential measurements; and BIA measurements of both limbs. From these measurements total limb volumes and extracellular fluid volumes were calculated and expressed as ratios of the affected limb to that of the unaffected limb. An index of the ratio of the extracellular fluid volume to the intracellular fluid volume was determined. This ECW/ICW index was calculated for both the affected and unaffected limbs at both measurement times. Results confirmed that the established techniques of total limb volume and extracellular fluid volume normalized to the unaffected contralateral limb were accurate in the detection of lymphedema (p < 10(-6)). Comparison of the ECW/ICW index from the affected limb after diagnosis with that from the pre-surgery measurement revealed a significant (p < 10(-6)) and considerable (75%) increase. The results of this pilot study suggest that by using multiple frequency bioelectrical impedance analysis, an index of the ECW/ICW ratio can be obtained and this index appears to have an equal, or better, sensitivity than the other techniques in detecting lymphedema. More importantly, this index does not require normalization to another body segment and can be used to detect all types of peripheral edema including both unilateral and bilateral lymphedema.