A Prospective Cohort Study on Neck Lymph Node Mapping in Oral Cancers Using Methylene Blue Dye.

In the current scenario, the management of N0 neck in early-stage oral cancer is debatable, whether or not they should undergo elective neck dissection. Most of the time these patients are either over-treated or under-treated. Sentinel lymph node (SLN) biopsy is a good option to identify occult LN in this cohort of patients for guiding neck dissection. With a focus on SLN biopsy using methylene blue dye, this study aims to evaluate its feasibility and accuracy in node-negative oral squamous cell carcinoma. A prospective observational study was conducted involving operable squamous cell carcinoma patients with clinically and radiologically node-negative neck. Methylene blue was injected in the peritumoral area and after that SLN was identified and then neck dissection was completed. Of 47 patients, SLN was identified in 82.98%, with 53.85% having more than two SLN. Common locations were in levels IB, IA and IIA. Occult metastasis was observed in 12.82% of cases, predominantly in T2 patients. Sensitivity, specificity and NPV were 50%, 100% and 88.89% respectively. The study affirms the feasibility and accuracy of methylene blue-assisted SLN biopsy in oral cancer. Despite a high detection rate, methylene blue dye alone should not be used for SLN identification in oral cavity cancer. However, it can be used as an adjunct of lymphoscintigraphy to increase the yield of the procedure. Multi-institutional trials with larger cohorts may provide valuable insights and more information for comprehensively addressing the limitations of this technique and its broader applicability in decision-making, particularly in resource-constrained countries like India where lymphoscintigraphy is not readily accessible.

Is fluorometric sentinel lymph node biopsy in endometrial cancer necessary?

Objective: In this study, we collected perioperative and postoperative follow-up data from patients with endometrial cancer (EC) at different stages to evaluate the role of sentinel lymph node biopsy (SLNB) in endometrial cancer surgery. Methods: A total of 186 endometrial cancer patients undergoing radical hysterectomy from January 2018 to April 2022 were retrospectively analyzed. Patients were classified into four groups. Group A comprised patients diagnosed with stage IA grade 1 and 2 endometrioid EC who underwent SLNB. Group B comprised patients with stage IA grade 1 and 2 endometrioid EC who did not undergo SLNB. Group C comprised patients with higher-grade endometrioid EC, wherein systematic lymph node dissection was performed based on SLNB results. Group D comprised patients with higher-grade endometrioid EC who did not undergo SLNB and instead underwent direct systematic lymph node dissection. Clinical, pathological data, and follow-up information for all patients were collected. Results: In Group A and B, SLNB was performed on 36 out of 67 patients with IA stage 1 and 2 endometrial cancer, yielding a SLN positivity rate of 5.6%. There were no significant differences observed between the two groups regarding perioperative outcomes and postoperative follow-up. Conversely, among 119 patients with higher-grade endometrial cancer, 52 underwent SLNB, with 20 patients exhibiting SLN positivity, resulting in a SLN positivity rate of 38.4%. However, the decision to undergo SLNB did not yield significant differences in perioperative outcomes and postoperative follow-up among these patients. Conclusion: For stage IA grade 1 and 2 endometrioid EC, the incidence of lymph node positivity is low, omitting SLNB in this subpopulation is a feasible option. In other stages of endometrioid EC, there is no significant difference in perioperative and postoperative follow-up data between patients undergoing routine systematic lymphadenectomy and those undergoing systematic lymphadenectomy based on SLNB results. Therefore, if SLNB is not available, the standard procedure of PLND remains an option to obtain information about lymph node status, despite the surgical complications associated with this procedure.

A systematic review of the complications of skin puncturing procedures in the upper limbs of patients that have undergone procedures on the axilla or breast.

Background: The increasing incidence and prevalence of breast malignancies have led to increasing numbers of surgical interventions performed on the axilla and breast, including axillary lymph node dissection (ALND), sentinel lymph node biopsy (SLNB), and mastectomy. The risk of postoperative complications, like breast cancer-related lymphoedema (BCRL), can have significant deleterious cosmetic and quality of life effects. National guidelines and cancer councils publish recommendations to avoid skin puncturing procedures, such as venepuncture and intravenous (IV) cannulation, on arms ipsilateral to the surgical site to prevent BCRL occurrence. The initial trials that established a link between BCRL and skin puncture were conducted in the 1950s and 1960s; the evolution of surgical management of breast cancer has likely led to large decreases in complication rates. Methods: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, four databases were systematically searched for relevant articles. Eleven relevant articles were identified for inclusion in the final analysis. Updated Australian and New Zealand College of Anaesthetists & Faculty of Pain Medicine (ANZCA) guidelines were included in the analysis following their publication after the initial search had been completed. Results: The overall quality and quantity of evidence in this field is sufficient to conclude that skin puncturing procedures on ipsilateral arms should not be avoided in patients with previous breast or axillary surgery. The highest-quality and most recent available evidence does not support an association between BCRL and skin puncturing procedures. Policies and practices that advocate avoiding skin puncture procedures to prevent BCRL may lead to delays in clinical care. The 2023 ANZCA guidelines recommend against avoiding affected arms for peripheral access and suggest the removal of institutional policies preventing this practice. Conclusions: In patients that have undergone breast surgery or axillary procedures, venous access procedures can be safely performed on the ipsilateral arm. The evidence does not support overarching restrictions on using the ipsilateral arm without pre-existing lymphoedema.

The Use of Sentinel Lymph Node Biopsy in Patients Undergoing Mastectomy for DCIS.

BACKGROUND: Current guidelines do not recommend routine sentinel node biopsy (SLNB) for ductal carcinoma in situ (DCIS), except in the setting of mastectomy or microinvasive disease. This study aimed to evaluate national SLNB utilization in women undergoing upfront mastectomy for DCIS, identify predictors of SLNB utilization, and determine the percentage with a positive SLNB. METHODS: A retrospective cohort analysis was performed using the NCDB of women with clinical DCIS who underwent upfront mastectomy between 2012 and 2017. Demographic and clinicopathologic variables were compared between patients who underwent SLNB and those who did not. Multivariate logistic regression models were used to identify factors associated with SLNB utilization and positive SLNB. RESULTS: About 38,973 patients met inclusion criteria: 34,231 (88%) underwent SLNB and 4742 (12%) had no surgical axillary staging. Most patients were age 50-69 (51%), non-Hispanic White (71%), with private insurance (66%). On multivariate analysis, older patients were less likely to receive SLNB (P < .01), while patients with higher grade DCIS were more likely to undergo SLNB (P < .01). In those who underwent SLNB (n = 34,231), only 1,149 (3.4%) had nodal involvement. Non-Hispanic Black patients had increased odds of a positive SLNB (P < .01), while those with estrogen receptor positive disease were less likely to be node positive (OR 0.68, P < .001). CONCLUSIONS: While 88% of patients had a SLNB, only 3.4% were found to be node positive. Given this low rate, it is reasonable to consider SLNB omission in select patients with low grade, hormone receptor positive DCIS undergoing upfront mastectomy.

Axillary Reverse Mapping Aids in Reducing the Rates of Breast Cancer-Related Lymphedema in Underserved Ethnically Diverse Population.

BACKGROUND: Breast cancer-related lymphedema (BCRL) poses a significant risk following sentinel lymph node biopsy (SLNB) and axillary lymph node dissection (ALND), particularly affecting ethnic minorities, with a twofold increased risk. Axillary reverse mapping (ARM), a novel technique, shows potential in reducing BCRL rates, yet its utility in ethnic minorities lacks sufficient exploration. Therefore, our study aims to investigate the utility and outcomes of ARM on BCRL in an ethnic diverse group. METHODS: A retrospective chart review of ARM patients from January 2019 to July 2022 was conducted, monitoring patients over 24 months at 3-month intervals using SOZO® scores, with comparisons with preoperative baselines. RESULTS: Of the 212 patients, 83% belonged to ethnic minorities. SLNB was performed in 83%, ALND in 17%, and 62.3% underwent radiation therapy. Positive lymph nodes were found in 31.6%, with 22.2% exhibiting blue nodes and 25.9% exhibiting blue lymphatics. Of identified blue nodes, 70.2% were excised, including 51.5% crossover nodes. Lymphedema occurred in 3 patients, resulting in a BCRL rate of 1.4%. Compared with an historical BCRL incidence of 40.4% following ALND in ethnic minorities, our study reported a significantly lower rate of 8% (p < 0.001). CONCLUSION: The ARM procedure can significantly lower BCRL in ethnic minority groups. The combination of ARM and bioimpedance spectroscopy led to a remarkably low BCRL rate of 1.4%. Notably, none of the patients in our study developed an axillary recurrence at 24-month follow-up. Nevertheless, future studies with larger sample sizes are warranted to better understand the utility of the ARM technique in this population.

Mohs micrographic surgery in the surgical treatment paradigm of melanoma in situ and invasive melanoma: A clinical review of treatment efficacy and ongoing controversies.

Mohs Micrographic Surgery (MMS) for treatment of melanoma offers several advantages over wide local excision (WLE), including complete histologic margin evaluation, same-day resection and closure, and sparing of healthy tissue in critical anatomic sites. Recently, a large volume of clinical data demonstrating efficacy in MMS treatment of melanoma was published, leading to emerging patient safety considerations of incurred treatment costs, risk of tumor upstaging, and failure of care coordination for sentinel lymph node biopsy (SLNB). MMS offers a safe, effective, and value-based treatment for both melanoma in situ (MIS) and invasive melanoma (IM), particularly with immunohistochemistry use on frozen sections. Compared to wide local excision, MMS treatment demonstrates similar or improved outcomes for local tumor recurrence, melanoma-specific survival, and overall survival at long-term follow-up. Tumor upstaging risk is low, and if present, alteration to clinical management is minimal. Discussion of SLNB for eligible head and neck IM cases should be done prior to MMS. Though challenging, successful multidisciplinary coordination of SLNB with MMS has been demonstrated. Herein, we provide a detailed clinical review of evidence for MMS treatment of cutaneous melanoma and offer recommendations to address current controversies surrounding the evolving paradigm of surgical management for both MIS and invasive melanoma (IM).

Staff radiation doses during Sentinel Lymph Node procedure of breast cancer from injection to surgeon.

The Sentinel Lymph Node (SLN) or Sentinel Lymph Node Biopsy (SLNB) technique involves various professionals from different departments in clinical settings to manage breast cancer patients properly. Tracing the nodular involvement of breast cancer patients requires radiation source Tc99m labeled with colloidal albumin to be injected at the tumor site. The patient becomes a radiation source for a sufficient time, which concerns the Nuclear Medicine (NM) and surgical staff. The study aims to provide the radiation doses of staff in the NM department during the SLN scintigraphy procedure and obtain an empirical model for calculating the radiation doses to staff in the surgical department from that particular patient. Radiation doses in SLN technique for breast cancer patients are minimal, and a sufficient number of SLN biopsy procedures can be performed by hospital staff within the category of non-radiation workers.

vNOTES surgical staging for endometrial carcinoma in overweight patients: a case series.

OBJECTIVES: The purpose of this study is to show the feasibility and surgical outcome of vNOTES retroperitoneal dissection and isolation of sentinel lymph nodes in overweight and obese patients with endometrial cancer. MATERIALS AND METHODS: Four patients had undergone pelvic lymphadenectomy with a sentinel lymph node. Three patients were overweight, and one was obese with a BMI of 34.6 kg/m2. By using NMR mode sentinel lymph node was visualized, excised and marked separately for pathohistological analysis from the rest of the visualized lymph nodes that were then consecutively excised. RESULTS: The mean number of overall excised lymph nodes was 12.5, and the mean number on the right side was 5.75 and 6.25 on the left side. There were no metastases verified in the pathohistological evaluation. CONCLUSION: vNOTES retroperitoneal isolation of sentinel lymph nodes is good alternative and has its benefits, especially in overweight and obese patients with satisfying low intra- and postoperative complications.

Prognostic significance of sentinel lymph node biopsy in elderly with cutaneous melanoma: systematic review and meta-analysis.

Sentinel lymph node biopsy is the most powerful prognostic indicator to date for cutaneous melanoma. Even though elderly patients have a lower incidence of sentinel node involvement, its results are still necessary for access to adjuvant therapies. This is highly relevant considering that the Western population shows an aging trend, and the incidence of melanoma has grown exponentially over the years, making elderly patients more likely to die from melanoma than younger ones. We performed a systematic review to investigate the prognostic significance of sentinel lymph node biopsy in elderly patients with melanoma. The systematic review was conducted following the PRISMA guidelines and registered in PROSPERO. The authors searched the Cochrane Database, EMBASE, PubMed, and WOS. Eligible studies for the systematic review were clinical trials, observational population studies, clinical or hospital-based cohort studies, and case-control studies. The meta-analysis was conducted using the R software program applying the meta package. Six reports were identified to meet the inclusion criteria. All studies were retrospective, non-randomized cohorts. The results obtained in this systematic review show a statistically significant influence of sentinel lymph node biopsy on disease-specific survival (HR = 2.87; 95% CI: 1.73-4.74) but also suggest that a positive result negatively impacts disease-free survival (HR = 3.41; 95% CI: 0.96-12.11). This meta-analysis shows that a positive sentinel lymph node biopsy does not imply differences in overall survival but significantly influences disease-specific survival and suggests an unfavorable impact on disease-free survival.

Sentinel lymph node biopsy for melanoma in the older population: A prospective analysis of outcomes.

BACKGROUND: The use of sentinel lymph node biopsy (SLNB) in the older population, defined as those over 70 years old, has been debated since the adoption of SLNB into routine practice. Interestingly, there remains a paucity of evidence, especially regarding the rates of SLNB positivity, complications, and subsequent adjuvant therapy in those with node positivity. METHOD: Data on patient's comorbidities, positivity rates, complication rates, and subsequent adjuvant treatments were collected prospectively from 998 patients (644 patients < 70 and 354 patients ≥ 70 years old) between 2016 and 2022. RESULTS: Patients aged ≥ 70 were found to have a higher prevalence of comorbidities, including hypertension, diabetes and hyperlipidaemia. The mean Breslow thickness was 2.2 and 2.5 in the under and over 70 groups respectively (p = 0.03). The mean mitotic rate was found to be 3.3 in the under 70 s and 4.1 in the over 70 s (p = 0.02). Despite these results, no significant differences were observed in the positivity rates of sentinel lymph node biopsies or in the treatment options selected for positive results. The under 70 s were more likely to experience loss of sensation (p < 0.01), but no difference was found in the total number of complications between the two groups. CONCLUSION: Although patients aged 70 and above had a greater incidence of comorbidities, the study revealed that they had lower complications rates and there was no significant variation in the SLNB positivity rate or chosen treatment options between the two age groups. This study supports the move to physiological rather than chronological age assessments in SLNB of the elderly.

An exploratory study of whether axillary lymph node dissection can be avoided in breast cancer patients with positive lymph nodes.

Background: Breast cancer patients with positive axillary lymph nodes usually require axillary lymph node dissection (ALND), with many postoperative complications, such as lymphedema. For these patients, whether sentinel lymph node biopsy (SLNB) can replace ALND has been a research hotspot in the field of breast cancer. This study developed two risk stratification models for predicting the clinical outcomes of breast cancer patients with positive axillary lymph nodes receiving SLNB alone or ALND to determine which patients could potentially avoid ALND. Methods: A total of 21,942 breast cancer patients, including a training set (n=15,362) and a testing set (n=6,580), were enrolled in this study from Surveillance, Epidemiology, and End Results (SEER) between 2000 and 2017. The risk factors associated with breast cancer-specific survival (BCSS) and overall survival (OS) were evaluated using multivariate Cox regression analysis and then integrated into nomograms and risk stratification models examined by receiver operating characteristic (ROC) curves and calibration curves. The survival discrepancies were compared between the SLNB and ALND subgroups with different risk scores with Kaplan-Meier plots. Results: In multivariate Cox regression analyses, grade, marital status, T stage, radiotherapy and lymph node metastasis (GMTRL) were independent risk factors in breast cancer patients with both OS and BCSS status in the ALND cohort from the training set. Nomograms have been developed based on these factors to predict 3- and 5-year OS and BCSS in patients with ALND. Calibration curves and ROC curves in both the training and testing sets confirmed the excellent overall predictive performance of the nomograms. Furthermore, we developed two risk stratification models based on OS and BCSS status, revealing that patients with low GMTRL scores might avoid ALND in both OS and BCSS status [OS: hazard ratio (HR) =0.929, 95% confidence interval (CI): 0.841-1.027, P=0.150; BCSS: HR =0.953, 95% CI: 0.831-1.094, P=0.495], but patients with moderate (OS: HR =0.756, 95% CI: 0.666-0.859, P<0.001; BCSS: HR =0.643, 95% CI: 0.537-0.768, P<0.001) and high GMTRL scores could not (OS: HR =0.719, 95% CI: 0.549-0.940, P=0.014; BCSS: HR =0.731, 95% CI: 0.549-0.974, P=0.031). Conclusions: Breast cancer patients with positive nodes could be treated with SLNB alone rather than ALND without affecting prognosis based on GMTRL scores. Patients with high or moderate GMTRL scores benefited greatly from ALND, but not for patients with low GMTRL scores. This study may assist clinicians in tailoring treatments.

Reliability of predicting low-burden (≤ 2) positive axillary lymph nodes indicating sentinel lymph node biopsy in primary operable breast cancer - a retrospective comparative study with PET/CT and breast MRI.

BACKGROUND: Sentinel lymph node biopsy (SLNB) is the standard of care for axillary staging in early breast cancer patients with low-burden axillary metastasis (≤ 2 positive nodes). This study aimed to determine the diagnostic performances of 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) and breast magnetic resonance imaging in detecting axillary lymph node (ALN) metastases and the reliability to predict ALN burden. METHODS: A total of 275 patients with primary operable breast cancer receiving preoperative PET/CT and upfront surgery from January 2001 to December 2022 in a single institution were enrolled. A total of 244 (88.7%) of them also received breast MRI. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of PET/CT and breast MRI were assessed. The predictive values to determine ALN burden were evaluated using radio-histopathological concordance. RESULTS: PET/CT demonstrated a sensitivity of 53.4%, specificity of 82.1%, PPV of 65.5%, NPV of 73.5%, and accuracy of 70.9% for detecting ALN metastasis, and the corresponding values for MRI were 71.8%, 67.8%, 56%, 80.8%, and 69.2%, respectively. Combining PET/CT and MRI showed a significantly higher PPV than MRI (72.7% vs 56% for MRI alone, p = 0.037) and a significantly higher NPV than PET/CT (84% vs 73.5% for PET/CT alone, p = 0.041). For predicting low-burden axillary metastasis (1-2 positive nodes), the PPVs were 35.9% for PET/CT, 36.7% for MRI, and 55% for combined PET/CT and MRI. Regarding patients with 0-2 positive ALNs in imaging, who were indicated for SLNB, the predictive correctness was 96.1% for combined PET/CT and MRI, 95.7% for MRI alone, and 88.6% for PET/CT alone. CONCLUSIONS: PET/CT and breast MRI exhibit high predictive values for identifying low-burden axillary metastasis in patients with operable breast cancer with ≦ 2 positive ALNs on imaging.

Role of Concurrent Ultrasound Surveillance of Sentinel Node-Positive Node Fields in Melanoma Patients Having Routine Cross-Sectional Imaging.

PURPOSE: In sentinel node-positive (SN+ve) melanoma patients, active surveillance with regular ultrasound examination of the node field has become standard, rather than completion lymph node dissection (CLND). A proportion of these patients now receive adjuvant systemic therapy and have routine cross-sectional imaging (computed tomography [CT] or positron emission tomography [PET]/CT). The role of concurrent ultrasound (US) surveillance in these patients is unclear. The purpose of our study was to describe the modality of detection of nodal recurrence in SN+ve node fields. METHODS: SN+ve melanoma patients who did not undergo CLND treated at a single institution from January 1, 2016 to December 31, 2020 were included. RESULTS: A total of 225 SN+ve patients with a median follow-up of 23 months were included. Of these, 119 (53%) received adjuvant systemic therapy. Eighty (36%) developed a recurrence at any site; 24 (11%) recurred first in the SN+ve field, of which 12 (5%) were confirmed node field recurrence only at 2 months follow-up. The nodal recurrences were first detected by ultrasound in seven (3%), CT in seven (3%), and PET/CT in seven (3%) patients. All nodal recurrences evident on US were also evident on PET/CT and vice versa. CONCLUSIONS: The high rate of recurrences outside the node field and the identification of all US-detected nodal recurrences on concurrent cross-sectional imaging modalities suggest that routine concurrent ultrasound surveillance of the node-positive field may be unnecessary for SN+ve melanoma patients having routine cross-sectional imaging.

A new fluorescenttargeting tracer contrasts dual tracers in sentinel lymph node biopsy of breast cancer.

Purpose: To explore the clinical application value of indocyanine green (ICG)-rituximab in sentinel lymph node biopsy. Methods: This study included 156 patients with primary breast cancer: 50 patients were enrolled in dose-climbing test, and 106 patients were enrolled in verification test. This was to compare the consistency of ICG-rituximab and combined method in the detected lymph nodes. Results: According to the verification test, the imaging rate of ICG-rituximab was 97.3%. Compared with the combined method, the concordance rate of fluorescence method was 0.991 (28 + 78/107; p < 0.001). Conclusion: For ICG-rituximab as a fluorescent targeting tracer, the optimal imaging dose of ICG 93.75 µg/rituximab 375 µg can significantly reduce the imaging of secondary lymph nodes. Compared with the combined method, it has a higher concordance rate.

Primary Melanoma Histopathologic Predictors of Sentinel Lymph Node Positivity: A Proposed Scoring System for Risk Assessment and Patient Selection in a Clinical Setting.

Background and Objectives: The careful selection of adequate SLNB candidates not only aims at reducing the surgical risk while identifying SLN metastasis, but also plays a crucial role in identifying the patients eligible for adjuvant therapy. Objectives: The purpose of our study was to investigate the clinical and histologic aspects of primary melanomas that correlate with the likelihood of a positive SLNB result. Materials and Methods: A total of 101 primary melanoma patients who underwent sentinel lymph node biopsies were included in the study. General patient demographics were obtained as well as localization and melanoma-specific characteristics of primary melanoma from histologic reports in addition to data derived from SLNB melanoma histopathology reports. Results: The patients with positive SLN results had a statistically significant increased Breslow thickness (3.8 mm vs. 1.97 mm, p = 0.002), higher mitotic index rate (5/mm2 vs. 2/mm2, p = 0.009), as well as the presence of ulceration (68.4% vs. 31.6%, p = 0.007). Univariate regression analysis showed the Breslow thickness (p = 0.008), the mitotic index rate (p = 0.054), the presence of ulceration (p = 0.009), as well as the pT3-4 stage (p = 0.009) to be significant predictors of SLN positivity. The optimal cut-off values for Breslow thickness and the number of mitoses scores were determined based on ROC curve analysis. Using the Breslow thickness, mitotic index rate, presence of ulceration, and pT3-4 stage significant coefficients from the univariate regression model, a chance prediction score was developed. Conclusions: The newly developed and proposed scoring system can aid in patient selection for SLN biopsy by facilitating a more efficient risk assessment in the detection of lymph node metastases in melanoma patients.

Noninvasive Staging of Lymph Node Status in Breast Cancer Using Machine Learning: External Validation and Further Model Development.

BACKGROUND: Most patients diagnosed with breast cancer present with a node-negative disease. Sentinel lymph node biopsy (SLNB) is routinely used for axillary staging, leaving patients with healthy axillary lymph nodes without therapeutic effects but at risk of morbidities from the intervention. Numerous studies have developed nodal status prediction models for noninvasive axillary staging using postoperative data or imaging features that are not part of the diagnostic workup. Lymphovascular invasion (LVI) is a top-ranked predictor of nodal metastasis; however, its preoperative assessment is challenging. OBJECTIVE: This paper aimed to externally validate a multilayer perceptron (MLP) model for noninvasive lymph node staging (NILS) in a large population-based cohort (n=18,633) and develop a new MLP in the same cohort. Data were extracted from the Swedish National Quality Register for Breast Cancer (NKBC, 2014-2017), comprising only routinely and preoperatively available documented clinicopathological variables. A secondary aim was to develop and validate an LVI MLP for imputation of missing LVI status to increase the preoperative feasibility of the original NILS model. METHODS: Three nonoverlapping cohorts were used for model development and validation. A total of 4 MLPs for nodal status and 1 LVI MLP were developed using 11 to 12 routinely available predictors. Three nodal status models were used to account for the different availabilities of LVI status in the cohorts and external validation in NKBC. The fourth nodal status model was developed for 80% (14,906/18,663) of NKBC cases and validated in the remaining 20% (3727/18,663). Three alternatives for imputation of LVI status were compared. The discriminatory capacity was evaluated using the validation area under the receiver operating characteristics curve (AUC) in 3 of the nodal status models. The clinical feasibility of the models was evaluated using calibration and decision curve analyses. RESULTS: External validation of the original NILS model was performed in NKBC (AUC 0.699, 95% CI 0.690-0.708) with good calibration and the potential of sparing 16% of patients with node-negative disease from SLNB. The LVI model was externally validated (AUC 0.747, 95% CI 0.694-0.799) with good calibration but did not improve the discriminatory performance of the nodal status models. A new nodal status model was developed in NKBC without information on LVI (AUC 0.709, 95% CI: 0.688-0.729), with excellent calibration in the holdout internal validation cohort, resulting in the potential omission of 24% of patients from unnecessary SLNBs. CONCLUSIONS: The NILS model was externally validated in NKBC, where the imputation of LVI status did not improve the model's discriminatory performance. A new nodal status model demonstrated the feasibility of using register data comprising only the variables available in the preoperative setting for NILS using machine learning. Future steps include ongoing preoperative validation of the NILS model and extending the model with, for example, mammography images.

Variability of Sentinel Lymph Node Location in Patients with Trunk Melanoma.

(1) Background: Melanoma is one of the most aggressive types of neoplasia, and the management of this pathology requires a correct staging, as well as a personalized modern oncological treatment. The main objective of the study is to determine the variability of the lymphatic drainage for patients with melanomas located on the trunk and, secondarily, to determine the features of individuals who underwent sentinel lymph node biopsy (SLNB) depending on the exact location on the trunk. (2) Methods: This retrospective, observational, single-center study included 62 cases of trunk melanoma operated between July 2019 and March 2023, in which SLNB was performed and a total of 84 lymph nodes were excised. (3) Results: Patients had a median age of 54.5 (33-78) years, with 58.1% being male; the melanomas had a median Breslow index of 2.3 (0.5-12.5) mm. Approximately 64.3% of the cohort had melanoma on the upper part of the trunk (54 cases) and 35.7% had it on the lower part (30 cases). The type of anesthesia chosen was general anesthesia in 53 cases and spinal anesthesia in 9 cases (85.5% vs. 14.5%, p < 0.001). The number of sentinel lymph nodes excised was 54 for melanomas located on the upper part of the trunk (8 cervical and 46 axillary) and 30 sentinel lymph nodes for melanomas of the lower part of the trunk (16 at the axillary level and 14 at the inguinal level). Out of the 54 LNs identified in patients with melanoma on the upper part of the trunk, 13 were positive, with a total of 12 positive lymph nodes (LNs) from the axillar basin, and only one from the cervical region. Additionally, the incidence of patients with a minimum of two identified sentinel lymph nodes was 32.2%, with a total of seven having LN involvement in two basins, and only one of these cases showed positivity for malignancy. (4) Conclusions: SLNBs were more frequent in the axillary region overall, and had more positive SLNs. Moreover, melanoma on the upper part of the trunk had a higher rate of positive SLNs compared to the lower part. Tumors located on the lower part of the truck had more positive SLNs in the axillary region than in the inguinal one.