TISSUE DIELECTRIC CONSTANT AS AN INDEX OF SKIN WATER IN WOMEN WITH AND WITHOUT BREAST CANCER: UPPER LIMB ASSESSMENT VIA A COMPACT DEVICE

Objective. The goals of the study were to utilize the portable device to assess age-related differences of tissue dielectric constant (TDC) between younger healthy women vs. women with breast cancer, upper-arm site differences in women with breast cancer, and the device\u27s limitations of a single measurement vs. averaged triplicate measurements. Background. Previous work showed tissue dielectric constant measurements at 300 MHz useful to evaluate local skin water and showed a new hand-held compact version provided values similar to an original multi-probe system when assessed in healthy subjects. Methods. A total of 84 women were included; 42 were young self-described healthy women and 42 were older women with recently diagnosed breast cancer who were awaiting surgery. In both groups tissue dielectric constant values were assessed on the anterior forearm. Women diagnosed with breast cancer were also measured at the hand, forearm, and biceps with all measurements bilateral and in triplicate. Results. Results showed the following. (1) Forearm TDC values are similar for the younger and older groups with no significant differences (NSD) between groups or between dominant and non-dominant sides or inter-arm ratios. (2) Hand TDC values are 21% greater than forearm and biceps values for hand, forearm and biceps of 1.027+/-0.180, 0.997+/-0.066 and 1.010+/-0.075 respectively. (3) Based on limits of agreement analyses, single TDC measurements are adequate for most forearm and biceps evaluations but multiple measurements are needed for hand measurements. (4) Theoretical detection thresholds for unilateral lymphedema using a 3SD limit of inter-arm ratios are 1.57, 1.20, and 1.24 for hand, forearm, and biceps. Conclusion. These values indicate likely useful forearm and biceps thresholds but are less useful ratio at the hand due primarily to the large variance in hand TDC values among patients. Grants. N

TISSUE DIELECTRIC CONSTANT (TDC) AS AN INDEX OF LOCALIZED ARM SKIN WATER: DIFFERENCES BETWEEN MEASURING PROBES AND GENDERS

Objective. Our goal was to compare measured tissue dielectric constant (TDC) values between multi-probe and compact-probe devices with respect to effective sampling depth, anatomical site and gender and to compare compact- probe TDC values measured on women with and without breast cancer (BC). Background. An easily measured non- invasive quantitative estimate of local skin tissue water is useful to assess local lymphedema and its change. One method uses skin TDC values at 300 MHz that depend on free and bound water. Until now such measurements used a research- type multi-probe but recently a hand-held compact-probe has become available that is more clinically convenient. Since most published data is based on multiprobe measurements it is important to characterize differences between devices that unless known might lead to ambiguous quantitative comparisons between TDC values. Methods. TDC was measured bilaterally on forearms and biceps of 32 male and 32 female volunteers and on 16 female patients awaiting surgery for breast cancer (BC). Results. 1) TDC values at 2.5 mm depth were less than at 1.5 mm; 2) Female TDC values were less than male values; 3) TDC values were not different between females with and without BC and 4) dominant/non- dominant arm TDC ratios were not different for any probe among genders or arm anatomical site. Conclusion. These findings indicate that probe-type differences in absolute TDC values are present and should be taken into account when TDC values are compared. But, comparisons based on inter-arm TDC ratios are not statistically different among probes with respect to gender or anatomical location. Grants. N/

Breast Tissue Dielectric Constant (TDC) Assessed in Women Having a Breast Tumor Biopsy

Objective. Determine TDC values of female breasts and effects of benign vs. malignant tumors. Background. TDC values can assess breast-cancer-treatment-related lymphedema. However, little is known about how breast TDC values are impacted by tumor-type (benign vs. malignant). Methods. Women (N=38) scheduled for a breast biopsy participated. Prior to biopsy, TDC was measured at; a standard-site bilaterally, over the tumor-site and at a similar healthy-breast site. Standard-site was adjacent and superior to the areola. TDC was measured with a probe that touched a breast for 5-seconds. Malignant-tumor patients (14) were older with larger tumors. Results: Standard-siteTDC values of biopsied vs. healthy-breasts (mean ± SD) were similar (30.9±4.3 vs. 30.5±4.7, N=38, p=0.317) and overall equal to 30.7±4.5. Tumor- carrying breast tumor-site values were greater than for healthy-breasts (31.9±6.7 vs. 30.3±6.5, N=38, p=0.009). Malignant-tumor TDC values (N=14) were greater than for healthy-breasts (32.6±6.2 vs. 29.0±5.9, p=0.008). Breasts with benign-tumors (N=24), showed no difference in TDC values between tumor vs. other breast (31.5±7.0 vs. 31.2±6.7, p=0.280). TDC at malignant-tumors was higher than standard-sites, but not statistically different (32.6±6.2 vs. 30.4±3.3, p=0.173.) Corresponding values on benign-tumor breasts were 31.5±7.0 vs. 31.2±4.8, p= 0.843). Conclusion: Results provide reference TDC values for standardized breast sites useful as comparison values for future studies about breast edema due to breast-cancer-treatment. Additionally, results show slightly greater TDC values at malignant-tumor sites vs. the contralateral healthy-breast site. However, it is not clear as yet if this difference is sufficient to provide useful diagnostic sensitivity of tumor type

Omission of Completion Lymph Node Dissection in Sentinel Node Biopsy Positive Head and Neck Cutaneous Melanoma Patients

BACKGROUNDRecent studies evaluating patients with a positive sentinel lymph node biopsy (SLNB+) show no melanoma-specific survival difference between patients undergoing lymph node basin surveillance and completion lymph node dissection (CLND). This has been broadly applied, despite underrepresentation of head and neck (HN) cutaneous melanoma patients. We evaluated whether this was upheld in the HN melanoma cohort. METHODSPatients with HN melanoma with a SLNB+ were selected from the National Cancer Database (NCDB) from 2012 to 2019. Overall survival (OS) of patients who underwent SLNB only versus SLNB + CLND were compared. Subgroup analyses were performed based on pathologic N (pN) and receipt of immunotherapy. Adjusted hazard ratio (aHR) and 95% confidence interval (CI) were calculated. RESULTSAnalysis of 634 patients with multivariable Cox regression showed no difference in OS in SLNB only versus SLNB + CLND cohorts (hazard ratio [HR] 1.13; 95% confidence interval [CI] 0.71-1.81; p = 0.610). Charlson-Deyo score (CDS) 1 versus 0 (HR 1.70; 95% CI 1.10-2.63; p = 0.016), pN2+ versus pN1 (HR 1.74; 95% CI 1.23-2.45; p = 0.002), and lymphovascular invasion (LVI) versus no (HR 2.07; 95% CI 1.34-3.19; p = 0.001) were associated with worse prognosis. Subgroup analysis by pN showed no OS benefit for CLND in either pN1 (HR 1.04; 95% CI 0.51-2.10; p = 0.922) or pN2+ (HR 1.31; 95% CI 0.67-2.57; p = 0.427) patients or in patients who received immunotherapy (HR 1.32; 95% CI 0.54-3.22; p = 0.549). CONCLUSIONSThis study of SLNB + HN melanoma patients showed no OS difference in SLNB only versus SLNB + CLND. Further studies need to be performed to better define the role of CLND