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

BACKGROUND: Recent 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. METHODS: Patients 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. RESULTS: Analysis 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). CONCLUSIONS: This 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.

Tissue Dielectric Constant Differentials between Malignant and Benign Breast Tumors.

INTRODUCTION: This study's purpose was to characterize tissue dielectric constant (TDC) values of malignant and benign breast tumors and assess the potential utility of TDC differentials to help distinguish between malignant and benign tumors. METHODS: Prior to their diagnostic biopsy, TDC was measured at 300 MHz in 59 women with previously detected breast tumors. TDC measurements were made by touching skin directly over the tumor and on the non-affected breast with a hand-held 22 mm diameter probe. Each measurement took less than 10 seconds. An inter-breast TDC ratio (RATIO) was calculated as the ratio of the tumor breast TDC value divided by the non-affected breast TDC value measured on the contralateral breast at a corresponding anatomical site. Absolute TDC values and RATIOS were compared for malignant and benign tumors based on post-measurement biopsy determinations. RESULTS: Biopsy findings indicated tumors were malignant in 29 patients and benign in 30. Compared to the non-affected breast, malignant tumor TDC values were greater (P = .0002) whereas for benign tumors, there was no inter-breast difference (P = .256). No patient with a benign tumor exceeded a RATIO of 1.15 whereas 12 of the 29 patients with malignant tumors exceeded this threshold and tended to have larger volume tumors. CONCLUSION: A tentative threshold RATIO of 1.15 may be discriminatory between malignant and benign tumors if the tumor is sufficiently large. Further research using a probe with a greater penetration depth is warranted to potentially increase discrimination.

Breast Tissue Dielectric Constant as a Potential Breast Edema Assessment Parameter.

Background: Many methods can quantitatively assess limb lymphedema, but methods to assess breast edema/lymphedema are quite limited. Thus, there is a need for a convenient and accurate way to quantify and track changes in this condition. Herein, breast tissue dielectric constant (TDC) values that depend on tissue water were used to obtain reference TDC values and interbreast TDC ratios. Methods and Results: TDC was measured in both breasts of 61 women who were about to undergo an ultrasound-guided diagnostic biopsy of a single mass (tumor) in 1 breast. Patient age and body mass index were (mean ± SD) 65.1 ± 11.6 (41-87 years) and 28.9 ± 5.1 (19.1-43.7 kg/m2). TDC was measured at a standardized site (12 o'clock position) with the TDC probe placed with its outer edge at the periphery of the subareolar region. TDC values of healthy breasts versus tumor breasts showed tumor breasts 3% greater (30.4 ± 4.6 vs. 29.5 ± 4.6, p = 0.02). Patients with benign tumors (N = 33) showed no difference between breasts (30.5 ± 4.4 vs. 30.8 ± 4.6 p = 0.434) and had an interbreast TDC ratio (tumor breast/healthy breast) of 1.013 ± 0.077. Patients with malignant tumors (N = 28) had tumor breast values 5% greater (29.8 ± 4.8 vs. 28.4 ± 4.6, p = 0.018) and an interbreast ratio of 1.056 ± 0.117. The overall interbreast ratio (N = 61) was 1.033 ± 0.099. Conclusion: Breast TDC values from nonedematous breasts provide the basis for calculating potential edematous/lymphedematous threshold values based on the measured means +2.5 standard deviation (SD). Accordingly, a TDC threshold value of 41 and an interbreast ratio of 1.28 were determined. These parameters have potential applicability for early detection in at-risk patients and those suspected of having breast edema/lymphedema.

Assessing localized skin-to-fat water in arms of women with breast cancer via tissue dielectric constant measurements in pre- and post-surgery patients.

BACKGROUND: Skin-to-fat tissue dielectric constant (TDC) values at 300 MHz largely depend on tissue water and provide a rapid way to assess skin water by touching skin with a probe for approximately 10 s. This method has been used to investigate lymphedema features accompanying breast cancer (BC), but relationships between TDC and nodes removed or symptoms is unclear. Our goals were: (1) to compare TDC values in BC patients prior to surgery (group A) and in patients who had BC-related surgery (group B) to determine if TDC of group B were related to nodes removed and reported symptoms and (2) to develop tentative lymphedema-detection thresholds. METHODS: Arm volumes and TDC values of at-risk and contralateral forearms and biceps were determined in 103 women awaiting surgery for BC and 104 women who had BC-related surgery 26.3 ± 17.5 months prior to evaluation. Inter-arm ratios (at-risk/contralateral) were determined and patients answered questions about lymphedema-related symptoms. RESULTS: Inter-arm TDC ratios for group A forearm and biceps were respectively 1.003 ± 0.096 and 1.012 ± 0.143. Group B forearm ratios were significantly greater, and among group B patients who reported at least one symptom there was a significant correlation between TDC ratios and symptom burden and nodes removed. CONCLUSIONS: Inter-arm TDC ratios are significantly related to symptoms and nodes removed. Ratios increase with increasing symptom score and might be used to detect pre-clinical unilateral lymphedema using TDC ratio thresholds of 1.30 for forearm and 1.45 for biceps. Threshold confirmation awaits targeted prospective studies but can serve as guideposts to provide quantitative and easily done tracking assessments during follow-up visits.

Patterns of temporal changes in tissue dielectric constant as indices of localized skin water changes in women treated for breast cancer: a pilot study.

BACKGROUND: Our goal was to characterize temporal patterns of skin Tissue Dielectric Constant (TDC) as a foundation for possible TDC use to detect and quantify lymphedema. Although limb volumes and bioimpedance analysis (BIA) are used for this purpose, potential TDC-method advantages are that it can be done in about 10 seconds at any body site to depths from 0.5 to 5.0 mm below the epidermis. METHODS AND RESULTS: TDC at forearm, biceps, axilla, and lateral thorax, and BIA values and arm volumes were measured in 80 women with breast cancer prior to surgery and in decreasing numbers at 3, 6, 12, 18, and 24 months post-surgery. Results show that TDC values, reflecting water content in the measurement volume, vary by site and depth but that at-risk/contralateral side ratio (A/C) is relatively independent of site and depth and is the preferred TDC parameter to detect tissue water changes over time in unilateral conditions. Among sites measured, lateral thorax, followed by forearm, appears most useful for TDC measurements with axilla least useful. Pre-surgery TDC inter-side values and A/C ratios showed no significant inter-side differences, suggesting that breast cancer presence per se did not alter tissue water status in this patient population. Sequential changes in TDC A/C ratios detected a greater number of patients who had inter-arm ratio increases exceeding 10% than were detected using BIA ratios. This may indicate a greater sensitivity to localized tissue water changes with the TDC-method. CONCLUSIONS: TDC is a technically viable and potentially useful method to track skin water changes in persons treated for breast cancer.

Local tissue water in at-risk and contralateral forearms of women with and without breast cancer treatment-related lymphedema.

BACKGROUND: Quantitative measurements to help detect incipient or latent lymphedema in patients at risk for breast cancer treatment-related lymphedema (BCRL) are potentially useful supplements to clinical assessments. Suitable measurements for routine use include arm volumes, arm bioimpedance, and local tissue water (LTW) determined from the tissue dielectric constant (TDC). Because BCRL initially develops in skin and subcutis, measures that include whole arms may not be optimally sensitive for detecting the earliest changes. Thus, there is also a need for a local measurement in which tissues most likely to demonstrate early lymphedematous changes can be more selectively assessed. The TDC method satisfies this criterion. Our goal was to use this method to compare arm-to-arm differences in LTW within and among women grouped as healthy normal (HN), diagnosed with breast cancer (BC), but prior to surgery and established unilateral lymphedema (LE). METHODS AND RESULTS: LTW was determined on both anterior forearms to a measurement depth of 2.5 mm in 30 women of each group. TDC arm ratios were determined as dominant/nondominant for HN and BC, at-risk/contralateral for BC, and lymphedematous/contralateral for LE. Results showed that TDC values for all arms except lymphedematous arms were very similar and insignificantly different with values among arms (mean +/- SD) ranging from 24.9 +/- 3.8 to 25.7 +/- 3.8. Arm ratios did not differ between HC and BC whereas dominant/non-dominant arm ratios for HN and BC separately and combined (1.006 +/- 0.085) were significantly less than the lymphedematous/contralateral ratio of the LE group (1.583 +/- 0.292). CONCLUSIONS: The findings indicate that LTW of at-risk arms is not affected by breast cancer and that lymphedema does not significantly affect LTW of contralateral arms as measured with the TDC method. Further, based on the standard deviation of measured arm ratios, an at-risk/contralateral TDC ratio of 1.26 is suggested as a possible threshold for detecting preclinical or latent lymphedema.