Patterns of Temporal Changes in Tissue Dielectric Constant as Indices of Localized Skin Water Changes in Women Treated for Breast Cancer: A Pilot Study

Breast Cancer-Related Lymphedema Assessed via Tissue Dielectric Constant Measurements

This review describes the use of tissue dielectric constant (TDC) measurements mainly in the assessment of breast cancer-related lymphedema (BCRL). PubMed, Web of Science, and EMBASE databases were initially searched using criteria that included the terms "dielectric" and "lymphedema." The initial search yielded a total of 131 titles. After removing studies not focused on upper extremity lymphedema, 56 articles remained. These articles, together with relevant articles from their bibliographies, formed the basis of the review. The findings show the potential utility and applications of TDC measurements to help detect and track BCRL, whether present in limbs, breasts, or trunks. It is reported as a non-invasive, simple-to-use method, with each measurement requiring less than 10 seconds, suggesting its practicality and useability as an in-office or in-clinic screening and tracking method. Although there are various ways to quantitatively evaluate lymphedema, most, if not all, are restricted to measurements on limbs. Thus, one significant advantage of the TDC approach is that almost any local region of interest can be effectively measured and tracked, which, for BCRL, could include specific regions of arms or hands, breasts, and truncal areas.

Medical Applications of Skin Tissue Dielectric Constant Measurements

Tissue dielectric constant (TDC) values assess certain skin properties that are dependent on multiple factors but mainly on the relative amount of water content within a locally measured tissue volume. Because of the non-invasive nature of these measurements and their ease of use, the method has been widely used in various medically related applications. The goal of this paper was to review and describe the uses and findings of such TDC measurements, considering and including the wide array of medical applications. The review is in part based on information derived from an analysis of published material obtained via literature searches of four major electronic databases and, in part, based on the author's experience with the TDC measurement methods and their various applications and his professional experiences. The databases searched were PubMed, Web of Science, EMBASE, and CINAHL Complete. Based on the initial search criteria, a total of 1257 titles were identified. After removing duplicates and filtering according to relevancy, 160 remained for detailed further review. In some cases, the bibliography of these retrieved articles provided additional sources. The findings demonstrate multiple research and medical uses and applications of TDC measurements, focusing on detecting and quantifying localized edema and lymphedema in multiple target sites. These include the upper and lower extremities, breasts, and trunk as regions involved in medical conditions causing lymphedema. In addition, the findings suggest that TDC evaluations are a convenient, non-invasive method to study and evaluate other conditions impacting skin, including diabetes mellitus and skin wounds or ulcers. Its ability to detect aspects of tissue changes simply and rapidly at almost any anatomical location makes it a useful tool for investigating multiple dermatological conditions and their treatment as future applications of this method.

Tissue Dielectric Constant and Skin Stiffness Relationships in Lower Extremity Lymphedema

Background: Lower extremity lymphedema or edema (LELE) may progressively transition from a state of excess tissue fluid to increased fat accumulation and collagen deposition, with tissue fibrosis and hardening. Such changes may lead to altered tissue water holding and thereby impact tissue dielectric constant (TDC). This study seeks to evaluate the relationship between TDC and tissue indentation force (TIF) in patients with LELE and assess the utility of the leg/arm TDC ratio (LAR) as an indicator of LELE. Methods and Results: Thirty females (49-91 years) with previously diagnosed LELE were evaluated during a scheduled session. TDC and TIF were measured 8 cm proximal to the medial malleolus on the medial and lateral aspects of both legs and on one forearm 8 cm distal to the antecubital fossa. The TDC-TIC relationship and the LAR were subsequently determined. Main results showed an absence of a significant correlation between TDC and TIF on medial or lateral leg sites but a positive correlation on the normal forearm site. Further, LAR values exceeded the published proposed threshold of 1.35 for 29/30 patients when using medial-side TDC values and 28/30 patients when using lateral-side TDC values. Conclusions: Findings suggest that for patients with LELE, TDC values are significantly elevated on medial and lateral standardized sites. The LAR determined using either medial or lateral sites that are similar to each other and have values consistent with a lymphedema threshold of 1.35. In edematous legs of the type evaluated herein, there is no apparent relationship between TDC values and indentation force.

Variation in Leg Tissue Dielectric Constant Values of Healthy Young Adult Females With and Without Compression Bandaging

Background The clinical efficacy of a compression application has been often limited to the assessment of the change in limb volume, change in clinical symptoms (i.e., wound size, pain, range of motion, incidence of cellulitis), or vascular hemodynamics of the whole limb. Assessing compression-related biophysical changes of a localized area, such as around a wound, or in an area outside of an extremity cannot be objectively assessed by these measurements. Tissue dielectric constant (TDC) values, which provide a measure of the local tissue water (LTW) content, offer an alternative method to document variation in the LTW content of the skin in a specific location. The goals of the present research were (1) to characterize TDC values, expressed as percentage tissue water, from multiple areas along the medial aspect of the lower leg of healthy volunteers and (2) to explore the potential utilization of the TDC values to assess change in tissue water content in a localized area following compression applications. Methods TDC was measured at 10, 20, 30, and 40 cm proximal to the medial malleolus on the medial aspect of the right leg of 18 young adult healthy women with an age range of 18-23 years and a body mass index of 18.7 to 30.7kg/m^2.. TDC was measured at baseline and after 10 minutes of exercise with compression in place on three separate days during which three different compression applications were assessed: a longitudinal elastic stockinette, a two-layer cohesive compression kit, and a combination of the two. Leg circumferences and compression-related interface pressures were also measured. Results Test-Retest Reliability of circumferential measurements and TDC values evaluated using Intraclass correlation coefficient (ICC _3,1) revealed excellent and moderate-to-good reliability, respectively. Analysis of TDC values along the length of the limb using Friedman's test, revealed a small but statistically significant overall difference among baseline TDC values attributable to a smaller value at 40 cm. The largest difference in cumulative average was 7.7% which occurred between 20 and 40 cm, with all other differences between locations less than 1%. No significant differences between the compression applications were observed. Conclusion  The present findings demonstrate the utility of TDC measurements as a modality to assess compression-related changes in the legs of healthy women as a foundation for their potential use in assessing outcomes of compression treatments for persons with lower extremity edema or lymphedema. The absence of a significant change in TDC values in these healthy non-edematous conditions and the demonstrated reliability of the TDC measurements on three different days provides further support for the utility of such applications of TDC measurements. The extension to patients with lower extremity edema or lymphedema needs to be evaluated.

The effect of adjuvant radiotherapy on skin biophysical properties in patients with breast cancer at risk for breast lymphedema: A prospective study

Breast cancer (BC) is the most common type of cancer among women. Radiotherapy (RT) is one of the main and primary treatment options for BC, especially in breast-conserving surgery (BCS). BC patients who underwent RT experience a wide range of symptoms, in which breast oedema and irritation of the skin take the lion's share. Breast oedema/lymphedema, which is also a prominent side effect after RT should be well determined in earlier settings due to the chronicity of lymphedema. Therefore, this study aimed to analyze the biophysical parameters of skin on the ipsilateral (IL) and contralateral (CL) sites via Tissue dielectric constant (TDC) and Transepidermal water loss (TEWL) methods in terms of oedema and skin barrier function (SBF). The following reference points before and after the RT were measured: (R1: Pectoralis muscle, R2: Upper breast, R3: Lower breast, R4: Lateral site of the thorax). A total of 24 BC patients (mean age and BMI: 52.78 ± 9.85 years and 28.42 ± 5.64 kg/m² ) were evaluated. In the IL site, the SBF was not found significant in R1-R3, whereas significantly lower SBF was observed in R4 after RT (t = -3.361, p = 0.003). A significant increase in TDC was observed in R2 at the 5.0 mm depth (t = -2.500, p = 0.02). We suggest that a longer period of follow-up should be carefully carried out to track changes in terms of SBF and oedema in the irradiated breast. The increased need for early detection of changes associated with breast lymphedema can be achievable via noninvasive, safe, cheap, and easily repeatable devices.

Assessment of local tissue water in breasts following breast reconstruction with an expander prosthesis or DIEP flap

The role of breast oedema in breast reconstruction is unknown. Therefore, our aim was to investigate local tissue water (LTW) and breast oedema-related symptoms in breasts reconstructed with either an expander prosthesis (EP) or with a deep inferior epigastric perforator (DIEP) flap at a minimum of one year postoperatively. Sixty-eight patients randomised to breast reconstruction with an EP or DIEP flap completed follow-up. Objective evaluation was performed at a mean of 25 (standard deviation, SD 9.5) months following breast reconstruction, and included measurements of breast volume and LTW with the MoistureMeterD® instrument. The patients completed the BREAST-Q questionnaire pre- and postoperatively. No significant differences in LTW were found when comparing EP and DIEP flap reconstructed breasts. The reconstructed breasts had an increase in LTW compared with the non-operated contralateral breasts. The BREAST-Q responses related to breast oedema symptoms were overall low and the median responses ranged from 1 to 2. A score of 1 indicated that symptoms were experienced 'None of the time'. Our findings indicate that mastectomy followed by breast reconstruction inflicts damage on the lymphatic system, shown as an increase in LTW. However, no breast oedema-related symptoms were reported in the BREAST-Q questionnaire, and therefore, we consider our objective results to be below a potential threshold for symptomatic breast oedema. A threshold for clinical indication of breast oedema remains to be defined.

Relation Between Early Disturbance of lymphatic transport Visualized With Lymphofluoroscopy and Other Clinical Assessment Methods in Patients With Breast Cancer

INTRODUCTION

Lymphedema of the upper extremity is one of the most feared complications following breast cancer treatment. Lymphofluoroscopy is a sensitive instrument for detection of lymphedema and visualization of superficial lymphatic transport, thus suitable for early detection. Early detection of lymphedema is important as it can prevent lymphedema to progress into more severe stages and minimalize impact on quality of life and medical costs.

OBJECTIVE

To determine agreement between the presence of early disturbance of the lymphatic transport and outcome of clinical measurement tools evaluating the development of lymphedema.

METHODS

A prospective study was conducted in 128 breast cancer patients scheduled for breast cancer surgery. Patients were evaluated before surgery and 1, 3-, 6-, 9-, and 12-months' post-surgery. Cohen's Kappa was used to determine agreement between presence of early disturbance in lymphatic transport and presence of pitting/increased skinfold thickness/increased Percentage Water Content ratio (PWC)/increased arm-hand volume (circumference measures and water displacement).

RESULTS

For pitting status (Kappa 0.23), for skinfold thickness (Kappa 0.29) and the PWC ratio (Kappa 0.21) a minimal agreement was found. The circumference measurement had a minimal agreement for 5% volume difference (Kappa 0.22) and no agreement for 3% volume difference (Kappa 0.19). Sensitivity was weak for all clinical assessments. The specificity was excellent for pitting status, skinfold thickness, PWC ratio, and for 5% volume difference. For 3% a high specificity was found.

CONCLUSION

The clinical tools assessed in this study were not able to predict an early disturbance of the lymphatic transport seen on lymphofluoroscopy.

Tissue Dielectric Constant Combined With Arm Volume Measurement as Complementary Methods in Detection and Assessment of Breast Cancer-Related Lymphedema

Aim: To investigate the role of tissue dielectric constant (TDC) in the detection and assessment of breast cancer-related lymphedema (BCRL) and to determine whether the TDC could potentially be used as a complementary method for arm volume measurement. Methods: Sixty-nine patients with BCRL were enrolled in this study. Local tissue water was assessed bilaterally by using the TDC method in four sites: upper arm, forearm, hand, and lateral thorax. Arm circumferences were measured at the 4-cm interval, starting from the shoulder to the wrist by using a tape measure. The arm volume was calculated by a standard formula. Patients' demographic information and clinical characteristics were also recorded. Results: Fifty-one of the 69 patients were diagnosed with clinical lymphedema. Using a TDC ratio of 1.2 or a diagnostic reference standard of ≥2 cm arm circumference, the sensitivity of these two methods was found to be identical at 73.9%. The TDC values in four sites on the affected side were significantly higher (p < 0.05) relative to the unaffected side. The inter-side TDC ratio of upper arm and forearm was substantially higher than that of lateral thorax and hand (p < 0.05). The TDC ratio of upper arm, forearm, and hand, especially of the upper arm and forearm, was positively correlated with inter-limb volume difference and stage of lymphedema. Conclusion: The TDC method elucidated a meaningful clinical correlation to the arm volume measurement. Applying those two methods together showed promise in the detection and assessment of BCRL. The forearm and upper arm were reliable examination sites for TDC measurements in the clinic.

An Approach Toward Assessing Head-and-Neck Lymphedema Using Tissue Dielectric Constant Ratios: Method and Normal Reference Values

Background: There are multiple methods to quantitatively assess limb lymphedema, but quantitative methods to assess external lymphedema in persons with head-and-neck lymphedema are quite limited. Quantification in this difficult condition currently uses multiple time-consuming head, face, and neck metric measurements, the accuracy of which is unclear. Thus, there is an important need for a new approach that is sufficiently convenient yet accurate to quantify head-and-neck lymphedema. The approach adopted was to use tissue dielectric constant (TDC) measurements that depend on tissue water, at neck and a submental area, and normalize these to TDC values at the forearm as a way to develop subject-independent indices. Methods and Results: TDC was measured in 60 self-reported healthy nonlymphedematous adults (34 female, 18-81 years, 18.5-45.7 Kg/m²) at two neck sites and one arm site bilaterally and at a submental area. Neck-to-arm-index (NAI) and submental-to-arm-index (SAI) ratios were calculated. TDC values (mean ± standard deviation [SD]) for neck, submental, and arm were, respectively, 37.4 ± 6.9, 35.9 ± 7.7, and 30.1 ± 4.6. Mean NAI and SAI values were 1.253 ± 0.222 and 1.214 ± 0.296 respectively. Head-and-neck lymphedema thresholds calculated as mean + 2.5 SD were for NAI and SAI 1.80 and 1.95, respectively. Conclusions: An approach to help quantify and track head-and-neck lymphedema using TDC neck and/or submental values normalized to a person's forearm TDC values indicates threshold values between 1.80 and 1.95. These ratios, denoted as NAI and SAI, are suggested for use to detect and track changes in lymphedema status based on a patient's changing indices associated with lymphedema treatment.

Tissue Dielectric Constant Measures in Women With and Without Clinical Trunk Lymphedema Following Breast Cancer Surgery: A 78-Week Longitudinal Study

OBJECTIVE

Following breast cancer surgery with lymph node removal, women are at risk of developing lymphedema in the upper extremity or trunk. Currently, trunk lymphedema diagnosis relies on a clinical assessment because no quantifiable standard method exists. Tissue dielectric constant (TDC) values are quantifiable measures of localized skin tissue water and may be able to detect trunk lymphedema. The goal of this study was to (1) compare parameters derived from TDC measurements with those derived from clinically accepted criteria for trunk lymphedema in women following breast cancer surgery and (2) explore the potential utility of TDC to detect trunk lymphedema early in its progression.

METHODS

This prospective longitudinal study, a secondary analysis from a larger study, observed women with and without clinically determined truncal lymphedema following breast cancer surgery. TDC was measured on the lateral trunk wall at post-surgery weeks 2, 4, 12, and 78 in women who had surgical breast cancer treatment with lymph node removal. Clinical assessment for trunk lymphedema was determined at 78 weeks by a lymphedema expert. Comparison of TDC measurements in women with and without clinical trunk lymphedema was analyzed.

RESULTS

Clinical assessment identified trunk lymphedema in 15 out of 32 women at 78 weeks. These women had TDC ratios statistically higher than women without truncal lymphedema.

CONCLUSION

The overall findings indicate that TDC has the ability to quantify trunk lymphedema and might be valuable in early detection.

IMPACT

TDC may be a beneficial tool in the early detection of breast cancer-related trunk lymphedema, which could trigger intervention.

LAY SUMMARY

A new device may help recognize trunk lymphedema in patients with breast cancer so they could receive appropriate treatment.

Heat-related changes in skin tissue dielectric constant (TDC)

The impact of 20 min of whole-body heating (WBH) on the tissue dielectric constant (TDC) of forearm and hand skin was evaluated in 24 young adults. TDC was measured in triplicate at 300 MHz using an open-ended transmission line method in which the effective measurement depth was about 2 mm. TDC measurements are an effective way to assess and track localized oedema and lymphoedema. The underlying hypothesis was that heat-induced eccrine gland activation would increase TDC values via an increase in fluid within the TDC measurement volume. The goal was to test this concept and to determine the magnitude of the change when environmental temperatures were elevated to near 42°C and to estimate TDC recovery time. The practical aspect of this research is motivated by the fact that patients in whom such measurements are made may arrive at the clinic in various states of sweat gland activation. Thus, knowledge of the effect of such activation on measured TDC values permits better understanding of possible relationships between such activation and TDC values. Results showed that increasing environmental temperature from 23·3 ± 1·6 to 41·5 ± 1·3°C increased forearm and thenar eminence skin temperatures to 37·8 ± 0·5 and 37·9 ± 0·4°C, respectively. These changes were associated with increases in TDC at arm from 30·7 ± 4·6 to 36·3 ± 5·7 (18·2%) and at hand from 34·7 ± 4·9 to 45·1 ± 5·5 (30%). Based on calculated TDC recovery rates, it is concluded that temperature-related TDC variability can be minimized using a wait time of at least 15 min after bandage removal prior to TDC measurements in affected limbs.

Compression Treatment of Breast Edema: A Randomized Controlled Pilot Study

Background: Patients treated for breast cancer with breast conserving surgery and radiotherapy (RT) often complain about swelling, heaviness, and pain in the treated breast. This pilot study was undertaken to examine if compression therapy was effective as an early treatment to reduce breast edema and symptoms assessed by Visual Analogue Scale (VAS). Methods and Results: Fifty-six breast cancer-treated women with breast edema, diagnosed by the measurement of tissue water content by tissue dielectric constant (TDC) technique 3 months post-RT, were randomized to either an intervention group, wearing a sports bra of compression type, or a control group, wearing a standard bra daily for 9 months when tissue water content in breast, upper arm, and lateral thorax of the operated side, and symptoms assessed by VAS were evaluated. No differences were found between the groups at start or end of study concerning tissue water content or VAS. However, within both groups, a significant reduction in tissue water content and experience of heaviness was found. Conclusion: Breast edema as well as experience of heaviness in the affected breast found at 3 months post-RT decreased after 9 months independent of whether a sports bra of compression type or a standard bra was used.

Assessment of local tissue water in the arms and trunk of breast cancer survivors with and without upper extremity lymphoedema

Given the paucity of information on local tissue water (LTW) in the upper extremity and trunk of women after breast cancer surgery, the purpose of this study was to compare tissue dielectric constant (TDC) values between the affected and unaffected sides of breast cancer survivors with and without upper extremity lymphoedema (LE). Differences in LTW were assessed using the TDC method for three sites in the upper limbs, three sites in the lateral thorax and two sites on the back. Additional measures included demographic and clinical characteristics, arm circumference and bioimpedance analysis. For the 112 survivors without LE, no differences in TDC values were found between the affected and unaffected sides for the first dorsal web space, ventral forearm and upper arm, and upper and lower back. Compared to the unaffected side, TDC values were significantly higher on the affected side for the upper, mid and lower lateral thorax. For the 78 survivors with LE, compared to the unaffected side, TDC was significantly higher on the affected side for all of the sites evaluated except the hand web space. Our findings support the use of the TDC method to detect differences in upper extremity and truncal oedema in survivors with LE following breast cancer treatment. Measurement of LTW may provide a useful method to determine truncal as well as extremity LE. The ability to detect early signs of truncal oedema may lead to pre-emptive interventions in breast cancer survivors.

Minimum Detectable Changes Associated with Tissue Dielectric Constant Measurements as Applicable to Assessing Lymphedema Status

Background: Tissue dielectric constant (TDC) measurements are increasingly being used as a tool to help characterize lymphedema features, detect its presence, and assess treatment related changes. Although the underlying physics of this technology has been well described in the literature, there has been little systematic study of in vivo reliability aspects. A central unanswered question is the minimal detectable change (MDC) that, with a given level of confidence, may be ascribed to this technology. Our goal was to address this issue using test-retest measurements from which intraclass correlations coefficients (ICC) and MDC could be estimated. Methods and Results: Forty volunteers (20 females) aged 19-61 years with body mass indices of 14.7-47 kg/m² and body fat percentages of 12.0%-48.9% were evaluated. Two measurers (M1 and M2) used two different TDC measuring devices (multiprobe and compact) to measure TDC in triplicate sequentially and bilaterally at three locations; anterior forearm, hand palmar mid-thenar eminence, and dorsum mid-web. These measurements were made by each measurer twice constituting test-retest values (T1 and T2). From these measurements ICC_2,1 and MDC at 95% confidence were determined for each site and probe for absolute TDC values and for inter-side ratios. MDC values for absolute TDC ranged from 2 to 9 TDC units, and for inter-side ratios ranged from 5.3% to 8.0% depending on site and probe. ICC_2,1 values ranged from 0.765 to 0.982. Conclusions: The MDC values herein documented may be used to provide guidance to aid interpretation of measured TDC changes or differences in a clinical environment.

Spatial and Temporal Variability of Upper Extremity Edema Measures After Breast Cancer Surgery

Background: Tissue dielectric constant (TDC), as an index of local tissue water, and girth measurements are quantitative methods to measure and characterize lymphedema. Objective: To describe the spatial and temporal variability in arm girth and TDC values in women surgically treated for breast cancer and to describe the relationship between these measures. Methods and Results: This was a prospective longitudinal study that observed 36 women for 78 weeks after breast cancer surgery with lymph node removal. Arm circumferences and TDC values, as indices of local tissue water, were measured on both arms at multiple sites at postsurgery weeks 2, 4, 12, and 78 in women undergoing surgical breast cancer treatment with one or more axillary lymph nodes removed. TDC and girth values remained relatively uniform from visit-to-visit for both at-risk and contralateral control arms with no overall statistically significant difference in values (p > 0.05). There was a strong inverse correlation between arm girth and the TDC value in both the at-risk and control arms (p < 0.001). Overall, there was no statistically significant difference in TDC interarm ratios among visits or anatomical sites. TDC values for at-risk and control arms tended to significantly decrease with increasing distance from the wrist (p < 0.001). Conclusion: TDC arm values and girth measures remained relatively uniform in women after breast cancer surgery. The fact that TDC values are higher distally than proximally provides new information from which TDC measurements may be interpreted and also provides a better understanding of arm spatial variability in relation to girth measures.

Role of handedness on forearm skin tissue dielectric constant (TDC) in relation to detection of early-stage breast cancer-related lymphedema

skin tissue dielectric constant (TDC) measurements help assess local skin water to detect incipient early-stage lymphedema subsequent to breast cancer treatment-related lymphedema. However, presurgery measurements are not always obtained and assessments for evolving lymphedema are only made after surgery. Thus, subsequent TDC assessments may be biased in an unknown way dependent on a patient's handedness in relation to the at-risk arm. We investigated this issue by comparing TDC values in dominant and non-dominant volar forearms of 31 left-handed women and 31 right-handed women (age range 24-84 years). Body fat and water percentages were assessed by bioimpedance at 50 KHz. Results showed that TDC values of dominant versus non-dominant arms did not significantly differ for left-handers or for right-handers. There was also no statistically significant difference in absolute TDC values between left- and right-handers or a statistically significant difference in dominant-to-non-dominant arm ratios between left- and right-handers. For the composite data set (N = 62), TDC values for dominant and non-dominant arms were, respectively, 30·0 ± 4·6 and 29·6 ± 4·2 and the dominant-to-non-dominant arm TDC ratio for combined left- and right-handers was 1·015 ± 0·075. These results suggest that handedness is not a major factor when assessing lymphedema status in women who have previously been treated for breast cancer but for whom pretreatment TDCvalues have not been obtained. Moreover, these results suggest that threshold ratios of incipient subclinical unilateral lymphedema based on interarm TDC ratios apply independent of a patient's handedness for the site and tissue depths herein measured.

Diagnosis of Upper Quadrant Lymphedema Secondary to Cancer: Clinical Practice Guideline From the Oncology Section of the American Physical Therapy Association

The Oncology Section of the American Physical Therapy Association (APTA) developed a clinical practice guideline to aid the clinician in diagnosing secondary upper quadrant cancer-related lymphedema. Following a systematic review of published studies and a structured appraisal process, recommendations were written to guide the physical therapist and other health care clinicians in the diagnostic process. Overall clinical practice recommendations were formulated based on the evidence for each diagnostic method and were assigned a grade based on the strength of the evidence for different patient presentations and clinical utility. In an effort to maximize clinical applicability, recommendations were based on the characteristics as to the location and stage of a patient's upper quadrant lymphedema.

Diagnosis of Upper-Quadrant Lymphedema Secondary to Cancer: Clinical Practice Guideline From the Oncology Section of APTA

INTRODUCTION

The Oncology Section of APTA developed a clinical practice guideline to aid the clinician in diagnosing secondary upper-quadrant cancer-related lymphedema.

METHODS

Following a systematic review of published studies and a structured appraisal process, recommendations were written to guide the physical therapist and other health care clinicians in their diagnostic process. Overall, clinical practice recommendations were formulated on the basis of the evidence for each diagnostic method and were assigned a grade based on the strength of the evidence for different patient presentations and clinical utility.

RECOMMENDATIONS

In an effort to make these clinically applicable, recommendations were based on the characteristics as to the location and stage of a patient's upper-quadrant lymphedema.

Open-Ended Coaxial Dielectric Probe Effective Penetration Depth Determination

We have performed a series of experiments which demonstrate the effect of open-ended coaxial diameter on the depth of penetration. We used a two layer configuration of a liquid and movable cylindrical piece of either Teflon or acrylic. The technique accurately demonstrates the depth in a sample for which a given probe diameter provides a reasonable measure of the bulk dielectric properties for a heterogeneous volume. In addition we have developed a technique for determining the effective depth for a given probe diameter size. Using a set of simulations mimicking four 50 Ω coaxial cable diameters, we demonstrate that the penetration depth in both water and saline has a clear dependence on probe diameter but is remarkably uniform over frequency and with respect to the intervening liquid permittivity. Two different 50 Ω commercial probes were similarly tested and confirm these observations. This result has significant implications to a range of dielectric measurements, most notably in the area of tissue property studies.

Experimental and Analytical Comparisons of Tissue Dielectric Constant (TDC) and Bioimpedance Spectroscopy (BIS) in Assessment of Early Arm Lymphedema in Breast Cancer Patients after Axillary Surgery and Radiotherapy

BACKGROUND

Early diagnosis of breast cancer treatment-related lymphedema (BCRL) is of great importance for longstanding treatment results. Tissue dielectric constant (TDC) and bioimpedance spectroscopy (BIS) both have a potential for early diagnosis, but have not been compared.

METHODS AND RESULTS

One hundred women, treated for breast cancer with breast surgery, axillary dissection, and radiotherapy, were examined within one year after breast cancer treatment, as part of the follow-up procedure. Affected/at-risk and contralateral arms were measured with the TDC technique specific to localized skin water content and the BIS technique assessing arm extracellular fluid (ECF). Thirty-eight patients were clinically diagnosed for lymphedema (38.0%). The sensitivity and specificity for the TDC method were 65.8% and 83.9%, and for BIS method 42.1% and 93.5%, (p < 0.001 and NS), respectively. Of all lymphedema, 18.4% were detected only by TDC and 2.6% by BIS. Affected arm to contralateral arm TDC ratios for upper arm and forearm, 1.56 ± 0.49 and 1.28 ± 0.33, demonstrating the localized feature of the TDC measurements were significantly greater than the BIS arm ratio 1.12 ± 0.12 (both p < 0.001).

CONCLUSIONS

Discrepancies between TDC and BIS techniques in assessing lymphedema are related to different measurement techniques and assessed tissue water components. Independently of selected technique-specific threshold limit, the TDC technique was more sensitive than the BIS technique in the early assessment of BCRL and demonstrated that nearly 20% of early lymphedema are only superficially localized. The results further supported the complementary role of TDC and arm volume measurements as a highly diagnostic method for early lymphedema.

Age-related changes in male forearm skin-to-fat tissue dielectric constant at 300 MHz

Prior research suggests that tissue dielectric constant (TDC) values are useful to assess localized skin water in females for early diagnosing breast cancer treatment-related lymphoedema and TDC values in young adults have shown gender differences. However, no TDC data are available for older males nor have ageing effects been studied despite known shifts in water state and other skin age-related changes. Thus our goals were to (i) characterize TDC values at various skin depths in young and older males, (ii) determine the dependence of these values on body composition parameters and (iii) establish inter-arm TDC ratios for use as normal male reference values. TDC measurements were made to depths of 0·5, 1·5, 2·5 and 5·0 mm bilaterally on volar forearm skin in 60 males in three groups of 20 that had mean ages ± SD of 24·0 ± 0·9, 40·0 ± 12·9 and 71·0 ± 8·0 years. Total body fat and water percentages were determined via bioimpedance at 50 KHz. Results showed that (i) for all age groups TDC values decreased with increasing depth, (ii) TDC values were not statistically different among age groups except at a depth of 0·5 mm, (iii) TDC values were highly negatively correlated with total body fat and (iv) inter-arm ratios varied little among age groups and depths. It is concluded that (i) age-related larger TDC values at only the shallowest depth is consistent with skin water shifting state from bound to more mobile in the oldest group and (ii) inter-arm ratios at any depth provide a basis to test for unilateral oedema.