Microscopic tumor burden in sentinel lymph nodes predicts synchronous nonsentinel lymph node involvement in patients with melanoma

"Percentage" and "size" of residual viable tumor in lymph node, the performance in estimating pathologic response of lymph node in non-small cell lung cancer treated with neoadjuvant chemoimmunotherapy

There is no universally accepted method for evaluating lymph node metastasis (LNM) in non-small cell lung cancer (NSCLC) after neoadjuvant chemoimmunotherapy. Different protocols recommend evaluating the percentage of residual viable tumor (RVT%) and metastatic tumor size (MTS). Our aim was to determine the prognostic significance of RVT% and MTS, and identify the more effective parameter for pathological evaluating LNM. Two independent cohorts were collected (derivation, n = 84; external validation, n = 42). All patients exhibited metastatic cancer or treatment response in lymph nodes post-surgery. In the derivation cohort, we assessed the mean and largest values of MTS and RVT% in LNM, estimating their optimal cutoffs for event-free survival (EFS) using maximally selected rank statistics. Validation was subsequently conducted in the external validation cohort. The quality of prognostic factors was evaluated using the Area Under Curve (AUC). A positive association was identified between RVT% and MTS, but an absolute association could not be conclusively established. In the derivation cohort, neither the largest MTS (cutoff = 6 mm, p = 0.28), largest RVT% (cutoff = 75%, p = 0.23), nor mean RVT% (cutoff = 55%, p = 0.06) were associated with EFS. However, mean MTS (cutoff = 4.5 mm) in lymph nodes was statistically associated with EFS (p = 0.018), validated by the external cohort (p = 0.017). The prognostic value of MTS exceeded that of ypN staging in both cohorts, as evidenced by higher AUC values. The mean value of MTS can effectively serve as a parameter for the pathological evaluation of lymph nodes, with a threshold of 4.5 mm, closely linked to EFS. Its prognostic value outperforms that of ypN staging.

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.

Lymphadenectomy After Melanoma-A National Analysis of Recurrence Rates and Risk of Lymphedema

INTRODUCTION

Treatment for melanoma after a positive sentinel lymph node biopsy includes nodal observation or lymphadenectomy. Important considerations for management, however, involve balancing the risk of recurrence and the risk of lymphedema after lymphadenectomy.

METHODS

From the Merative MarketScan Research Databases, adult patients were queried from 2007 to 2021. International Classification of Disease, Ninth (ICD-9) and Tenth (ICD-10) Editions, diagnosis codes and Current Procedural Terminology codes were used to identify patients with melanoma diagnoses who underwent an index melanoma excision with a positive sentinel lymph node biopsy (SLNB). Main outcomes were completion lymph node dissection (CLND) utilization after a positive SLNB, developing lymphedema with or without CLND, and nodal basin recurrence 3 months or more after index excision. Subanalyses stratified by index excision year (2007-2017 and 2018-2021) and propensity score matched were additionally conducted. Demographics and comorbidities (measured by Elixhauser index) were recorded.

RESULTS

A total of 153,085,453 patients were identified. Of those, 359,298 had a diagnosis of melanoma, and 202,456 patients underwent an excision procedure. The study cohort comprised 3717 patients with a melanoma diagnosis who underwent an excision procedure and had a positive SLNB. The mean age of the study cohort was 49 years, 57% were male, 41% were geographically located in the South, and 24% had an Elixhauser index of 4+. Among the 350 patients who did not undergo CLND, 10% experienced recurrence and 22% developed lymphedema. A total of 3367 patients underwent CLND, of which 8% experienced recurrence and 20% developed lymphedema. Completion lymph node dissection did not significantly affect risk of recurrence [odds ratio (OR), 1.370, P = 0.090] or lymphedema (OR, 1.114, P = 0.438). After stratification and propensity score matching, odds of experiencing lymphedema (OR, 1.604, P = 0.058) and recurrence (OR, 1.825, P = 0.058) after CLND were not significantly affected. Rates of CLND had significantly decreased (P < 0.001) overtime, without change in recurrence rate (P = 0.063).

CONCLUSIONS

Electing for nodal observation does not increase the risk of recurrence or reduce risk of lymphedema. Just as CLND does not confer survival benefit, its decreased utilization has not increased recurrence rate.

Sentinel lymph node assessment in melanoma: current state and future directions

Assessment of sentinel lymph node status is an important step in the evaluation of patients with melanoma for both prognosis and therapeutic management. Pathologists have an important role in this evaluation. The methodologies have varied over time, from the evaluation of dimensions of metastatic burden to determination of the location of the tumour deposits within the lymph node to precise cell counting. However, no single method of sentinel lymph node tumour burden measurement can currently be used as a sole independent predictor of prognosis. The management approach to sentinel lymph node-positive patients has also evolved over time, with a more conservative approach recently recognised for selected cases. This review gives an overview of past and current status in the field with a glimpse into future directions based on prior experiences and clinical trials.

Hot dots - which nodes should be removed in sentinel lymph node biopsy for melanoma?

BACKGROUND

Sentinel lymph node biopsy (SLNB) is a critical staging tool for melanoma patients. The optimal number of lymph nodes removed in SLNB remains unclear. In this study, we retrospectively analysed and tested different criteria for selecting sentinel lymph nodes (SLNs) by radiotracer uptake and blue dye, and their impact on nodal staging. We also evaluated the association between SLN tumour burden and radiotracer uptake.

METHODS

The study population consisted of melanoma patients undergoing SLNB. During the operation all radioactive and blue nodes were removed and sent for histopathological analysis. The ex vivo radioactive count and presence of blue dye of each node were recorded, and these were correlated with presence and size of metastasis in each SLN.

RESULTS

Altogether 175 patients with clinically occult metastasis presented with one or more positive, i.e. metastatic, SLNs. The mean number of lymph nodes removed was 4.5, and the mean number of positive lymph nodes was 1.5 per patient. The most radioactive or hottest node was negative in 38 patients (22%). By removing the hottest node and all nodes with radioactivity >10% of the hottest node, 97% of patients would have been staged correctly. In five patients, metastasis was found solely in a SLN with radioactivity <10% of the hottest node. Of all 267 positive nodes removed, 125 (47%) contained blue dye. Patients with a negative hottest node were associated with lower SLN tumour burden.

CONCLUSIONS

By removing the hottest node and all nodes with radioactivity >10% of the hottest node, 97% of patients with SLN metastases are correctly staged with or without using blue dye.

Cutaneous melanoma

Cutaneous melanoma is a malignancy arising from melanocytes of the skin. Incidence rates are rising, particularly in White populations. Cutaneous melanoma is typically driven by exposure to ultraviolet radiation from natural sunlight and indoor tanning, although there are several subtypes that are not related to ultraviolet radiation exposure. Primary melanomas are often darkly pigmented, but can be amelanotic, with diagnosis based on a combination of clinical and histopathological findings. Primary melanoma is treated with wide excision, with margins determined by tumour thickness. Further treatment depends on the disease stage (following histopathological examination and, where appropriate, sentinel lymph node biopsy) and can include surgery, checkpoint immunotherapy, targeted therapy, or radiotherapy. Systemic drug therapies are recommended as an adjunct to surgery in patients with resectable locoregional metastases and are the mainstay of treatment in advanced melanoma. Management of advanced melanoma is complex, particularly in those with cerebral metastasis. Multidisciplinary care is essential. Systemic drug therapies, particularly immune checkpoint inhibitors, have substantially increased melanoma survival following a series of landmark approvals from 2011 onward.

New Zealand patients have a higher melanoma burden in sentinel nodes and completion lymphadenectomy than patients in MSLT-II

New Zealand has the highest rate of melanoma-related mortality in the world. Access to immunotherapy and radiology is limited and surgical treatment of regional disease remains important. A recent pilot study of a single health district observed a higher nodal melanoma burden than was reported in the second Multicentre Selective Lymphadenectomy Trial (MSLT-II). In this study, a series of regional censuses were undertaken covering the 10 years immediately prior to the publication of MSLT-II. The study population was seven District Health Boards covering 62.2% of the population of New Zealand across a 10-year period preceding MSLT-II. The primary outcomes measured were the size of sentinel lymph node metastases and non-sentinel node (NSN) positivity on completion lymph node dissection (CLND) for patients with a positive sentinel lymph node biopsy (SLNB). In the 2323 SLNB identified, the mean sentinel lymph node metastatic deposit size was larger compared to MSLT-II (2.55 vs. 1.07/1.11 mm). A greater proportion of New Zealand patients (44.2%) had metastatic deposits larger than 1 mm compared to MSLT-II (33.2/34.5%) and the rate of non-sentinel node involvement on CLND was also higher (22.2% vs. 11.5%). These findings indicate that New Zealand is a high-risk population for nodal melanoma metastases. Due to these differences, the conclusions of MSLT-II may not be able to be applied to melanoma patients in the 7 regions studied in New Zealand.

Sentinel Lymph Node Biopsy for Extremity and Truncal Soft Tissue Sarcomas: A Systematic Review of the Literature

BACKGROUND

Regional lymph node metastasis (RLNM) occurs infrequently in patients with soft tissue sarcoma (STS), although certain STS subtypes have a higher propensity for RLNM. The identification of RLNM has significant implications for staging and prognosis; however, the precise impact of node-positive disease on patient survival remains a topic of controversy. Although the benefits of sentinel lymph node biopsy (SLNB) are well documented in patients with melanoma and breast cancer, whether this procedure offers a benefit in STS is controversial.

METHODS

A systematic literature search was performed and articles reviewed to determine if SLNB in patients with extremity/truncal STS impacts disease-free or overall survival.

RESULTS

Six studies were included. Rates of sentinel lymph node positivity were heterogeneous (range 4.3-50%). The impact of SLNB on patient outcomes remains unclear. The overall quality of available evidence was low, as assessed by the Grading of Recommendations, Assessment, Development, and Evaluation system.

CONCLUSIONS

The literature addressing the impact of nodal basin evaluation on the staging and management of patients with extremity/truncal STS is confounded by heterogeneous patient cohorts and clinical practices. Multicenter prospective studies are warranted to determine the true incidence of RLNM and whether SLNB could benefit patients with clinically occult RLNM at diagnosis.

Melanoma lymph node metastases - moving beyond quantity in clinical trial design and contemporary practice

The presence of lymph node metastases is a well-studied prognostic factor for cutaneous melanoma. Characterization of melanoma lymph node metastases and their association with survival in multiple, large observational studies has led to recognition of the following high-risk features: quantity of lymph node metastases (number of nodes), size of the nodal tumor deposit (in mm), and extracapsular extension. Despite increasing utilization of these features in the design of randomized clinical trials, in addition to their role in contemporary clinical decision-making, current staging systems lag behind, only accounting for the quantity of lymph nodes with metastases. Herein, we review the prognostic role of melanoma lymph node metastases and their high-risk features, current reporting standards, how such features have been utilized in practice-changing trials, and best practices for future clinical trial design and clinical decision-making.

Predictors of Nodal Metastasis in Cutaneous Head and Neck Cancers

PURPOSE OF REVIEW

The complex and varied drainage patterns in the head and neck present a challenge in the regional control of cutaneous neoplasms. Lymph node involvement significantly diminishes survival, often warranting more aggressive treatment. Here, we review the risk factors associated with lymphatic metastasis, in the context of the evolving role of sentinel lymph node biopsy.

RECENT FINDINGS

In cutaneous head and neck melanomas, tumor thickness, age, size, mitosis, ulceration, and specific histology have been associated with lymph node metastasis (LNM). In head and neck cutaneous squamous cell carcinomas, tumor thickness, size, perineural invasion, and immunosuppression are all risk factors for nodal metastasis. The risk factors for lymph node involvement in Merkel cell carcinoma are not yet fully defined, but emerging evidence indicates that tumor thickness and size may be  associated with regional metastasis. The specific factors that predict a greater risk of LNM for cutaneous head and neck cancers generally include depth of invasion, tumor size, mitotic rate, ulceration, immunosuppression, and other histopathological factors.

Therapeutic Value of Sentinel Lymph Node Biopsy in Patients With Melanoma: A Randomized Clinical Trial

Importance

Sentinel lymph node (SLN) biopsy is a standard staging procedure for cutaneous melanoma. Regional disease control is a clinically important therapeutic goal of surgical intervention, including nodal surgery.

Objective

To determine how frequently SLN biopsy without completion lymph node dissection (CLND) results in long-term regional nodal disease control in patients with SLN metastases.

Design, Setting, and Participants

The second Multicenter Selective Lymphadenectomy Trial (MSLT-II), a prospective multicenter randomized clinical trial, randomized participants with SLN metastases to either CLND or nodal observation. The current analysis examines observation patients with regard to regional nodal recurrence. Trial patients were aged 18 to 75 years with melanoma metastatic to SLN(s). Data were collected from December 2004 to April 2019, and data were analyzed from July 2020 to January 2022.

Interventions

Nodal observation with ultrasonography rather than CLND.

Main Outcomes and Measures

In-basin nodal recurrence.

Results

Of 823 included patients, 479 (58.2%) were male, and the mean (SD) age was 52.8 (13.8) years. Among 855 observed basins, at 10 years, 80.2% (actuarial; 95% CI, 77-83) of basins were free of nodal recurrence. By univariable analysis, freedom from regional nodal recurrence was associated with age younger than 50 years (hazard ratio [HR], 0.49; 95% CI, 0.34-0.70; P < .001), nonulcerated melanoma (HR, 0.36; 95% CI, 0.36-0.49; P < .001), thinner primary melanoma (less than 1.5 mm; HR, 0.46; 95% CI, 0.27-0.78; P = .004), axillary basin (HR, 0.61; 95% CI, 0.44-0.86; P = .005), fewer positive SLNs (1 vs 3 or more; HR, 0.32; 95% CI, 0.14-0.75; P = .008), and SLN tumor burden (measured by diameter less than 1 mm [HR, 0.39; 95% CI, 0.26-0.60; P = .001] or less than 5% area [HR, 0.36; 95% CI, 0.24-0.54; P < .001]). By multivariable analysis, younger age (HR, 0.57; 95% CI, 0.39-0.84; P = .004), thinner primary melanoma (HR, 0.40; 95% CI, 0.22-0.70; P = .002), axillary basin (HR, 0.55; 95% CI, 0.31-0.96; P = .03), SLN metastasis diameter less than 1 mm (HR, 0.52; 95% CI, 0.33-0.81; P = .007), and area less than 5% (HR, 0.58; 95% CI, 0.38-0.88; P = .01) were associated with basin control. When looking at the identified risk factors of age (50 years or older), ulceration, Breslow thickness greater than 3.5 mm, nonaxillary basin, and tumor burden of maximum diameter of 1 mm or greater and/or metastasis area of 5% or greater and excluding missing value cases, basin disease-free rates at 5 years were 96% (95% CI, 88-100) for patients with 0 risk factors, 89% (95% CI, 82-96) for 1 risk factor, 86% (95% CI, 80-93) for 2 risk factors, 80% (95% CI, 71-89) for 3 risk factors, 61% (95% CI, 48-74) for 4 risk factors, and 54% (95% CI, 36-72) for 5 or 6 risk factors.

Conclusions and Relevance

This randomized clinical trial was the largest prospective evaluation of long-term regional basin control in patients with melanoma who had nodal observation after removal of a positive SLN. SLN biopsy without CLND cleared disease in the affected nodal basin in most patients, even those with multiple risk factors for in-basin recurrence. In addition to its well-validated value in staging, SLN biopsy may also be regarded as therapeutic in some patients.

Trial Registration

ClinicalTrials.gov Identifier: NCT00297895.

Sentinel node tumor burden in cutaneous melanoma. Survival with competing risk analysis and influence in relapses and non-sentinel node status: retrospective cohort study with long follow-up in a Spanish population

Several authors have studied the potential of sentinel lymph node (SLN) tumor burden as prognostic factor but the microscopic classifications used in different study groups were variable. We examined the prognostic role of tumor burden in SLN on melanoma specific-survival and competing causes of death. We also analysed clinical and histological factors as predictors of disease relapses and additional non sentinel lymph node (NSLN) metastases. We included all patients with cutaneous melanoma that underwent SLN biopsy between 2002 and 2012 at Complejo Hospitalario de Navarra (Spain). The study end-points were death due to melanoma, melanoma relapse and involvement of NSLN. We used Fine-Gray test for competing risk analysis. A logistic regression model was performed to predict the risk of involvement of NSLN. Between 2002 and 2012, there were 348 patients who underwent SLN biopsy in our centre (308 were eligible for the study). 26.9% patients positive SLN. 88 patients died during the follow-up period and 66 (75%) died from melanoma. The 5-year cumulative incidence of melanoma death was 15.33% (95 % CI 15.25-15.42). The cumulative probability of death from melanoma was associated with gender, histological subtype, Breslow thickness, mitotic rate, ulceration and SLN tumor burden. In multivariable analysis, Breslow thickness and SLN tumor burden remained as independent prognostic factors. SLN tumor burden appears to be an important prognostic factor. It is very important reporting these characteristics in pathological reports. More prospective studies would be necessary to analyze these variables and to be able to make recommendations in management of melanoma patients.

Melanoma sentinel lymph node biopsy and completion lymph node dissection: A regional hospital experience

Completion lymph node dissection (CLND) following positive sentinel lymph node biopsy (SLNB) for cutaneous melanoma is a topic of controversy. The second Multicenter Selective Lymphadenectomy Trial (MSLT-II) suggested no survival benefit with CLND over observation amongst patients with a positive SLNB. The findings of the MSLT-II may have limited applicability to our high-risk population where nodal ultrasound and non-surgical melanoma treatment is rationed. In this regional, retrospective study, we reviewed primary melanoma, SLNB and CLND histopathological reports in the Bay of Plenty District Health Board (BOPDHB) across a 10-year period. The primary outcomes measured were size of sentinel lymph node metastases and non-sentinel node (NSN) positivity on CLND for patients with a positive SLNB. In the 157 SLNB identified, the mean sentinel lymph node metastatic deposit size was larger in BOPDHB compared with MSLT-II (3.53 vs 1.07/1.11mm). A greater proportion of BOPDHB patients (54.8%) had metastatic deposits larger than 1mm compared with MSLT-II (33.2/34.5%) and the rate of NSN involvement on CLND was also higher (23.8% vs 11.5%). These findings indicate that the BOPDHB is a high-risk population for nodal melanoma metastases. Forgoing CLND in the context of a positive SLNB may place these patients at risk.

Clinicopathologic models predicting non-sentinel lymph node metastasis in cutaneous melanoma patients: Are they useful for patients with a single positive sentinel node?

Background and Objectives

Of clinically node‐negative (cN0) cutaneous melanoma patients with sentinel lymph node (SLN) metastasis, between 10% and 30% harbor additional metastases in non‐sentinel lymph nodes (NSLNs). Approximately 80% of SLN‐positive patients have a single positive SLN.

Methods

To assess whether state‐of‐the‐art clinicopathologic models predicting NSLN metastasis had adequate performance, we studied a single‐institution cohort of 143 patients with cN0 SLN‐positive primary melanoma who underwent subsequent completion lymph node dissection. We used sensitivity (SE) and positive predictive value (PPV) to characterize the ability of the models to identify patients at high risk for NSLN disease.

Results

Across Stage III patients, all clinicopathologic models tested had comparable performances. The best performing model identified 52% of NSLN‐positive patients (SE = 52%, PPV = 37%). However, for the single SLN‐positive subgroup (78% of cohort), none of the models identified high‐risk patients (SE > 20%, PPV > 20%) irrespective of the chosen probability threshold used to define the binary risk labels. Thus, we designed a new model to identify high‐risk patients with a single positive SLN, which achieved a sensitivity of 49% (PPV = 26%).

Conclusion

For the largest SLN‐positive subgroup, those with a single positive SLN, current model performance is inadequate. New approaches are needed to better estimate nodal disease burden of these patients.

Sentinel Lymph Node Tumor Burden Using Digital Cell Count Estimation Predicts Outcomes in Melanoma

BACKGROUND

Cutaneous melanoma often metastasizes in primis to sentinel lymph nodes (SLNs). Currently, there is no standardized method of characterizing micrometastatic tumor burden in SLN biopsies for melanoma. Different criteria have been developed to evaluate SLN biopsies, yet none consider the number of cells identified.

AIM

Here, we used software analysis to digitally quantify metastatic tumor burden within SLNs and correlated these data with clinicopathologic and prognostic information.

METHODS

We identified 246 cases of SLN biopsies, including 63 positive (26%) and 183 (74%) negative for metastatic melanoma. Digital cell counting was performed within the greatest metastatic focus and the entire metastatic tumor burden within the same SLN.

RESULTS

Increasing cell count in the largest metastatic deposit correlated with the previously described Rotterdam (Spearman's r = 0.91; 95% CI: 0.84, 0.94), Starz (Spearman's r = 0.78; 95% CI: 0.68, 0.87), and Dewar criteria (p < 0.01), validating our method of using cell count to define SLN tumor burden. Additionally, increasing cell count was associated with decreased metastasis free survival (HR = 2.29; 95% CI: 1.22, 4.31).

CONCLUSION

These data support the use of computerized cell count analysis for prognostication of outcomes in patients undergoing SLN biopsy.

Management of Regional Nodal Melanoma

Regional nodal melanoma management has changed substantially over the past 2 decades alongside advances in systemic therapy. Significant data from retrospective studies and from 2 randomized controlled trials show no survival benefit to completion lymph node dissection compared with observation in sentinel lymph node-positive melanoma patients. Observation is becoming the standard recommendation in these patients, whereas patients with clinically detected lymph nodes are still recommended to undergo lymph node dissection. Promising early results from a neoadjuvant approach inform the ongoing evolution of melanoma management. Recruiting patients to clinical trials is paramount to attaining evidence-based practice changes in melanoma.

Survival in Patients With Sentinel Node-Positive Melanoma With Extranodal Extension

BACKGROUND

Prognostic parameters in sentinel node (SN)-positive melanoma are important indicators to identify patients at high risk of recurrence who should be candidates for adjuvant therapy. We aimed to evaluate the presence of melanoma cells beyond the SN capsule-extranodal extension (ENE)-as a prognostic factor in patients with positive SNs.

METHODS

Data from 1,047 patients with melanoma and positive SNs treated from 2001 to 2020 at the Istituto Nazionale dei Tumori in Milano, Italy, were retrospectively investigated. Kaplan-Meier survival and crude cumulative incidence of recurrence curves were estimated. A multivariable logistic model was used to investigate the association between ENE and selected predictive factors. Cox models estimated the effect of the selected predictors on survival endpoints.

RESULTS

Median follow-up was 69 months. The 5-year overall survival rate was 62.5% and 71.7% for patients with positive SNs with and without ENE, respectively. The 5-year disease-free survival rate was 54.0% and 64.0% for patients with positive SNs with and without ENE, respectively. The multivariable logistic model showed that age, size of the main metastatic focus in the SN, and numbers of metastatic non-SNs were associated with ENE (all P<.0001). The multivariable Cox regression models showed the estimated prognostic effects of ENE associated with age, ulceration, size of the main metastatic focus in the SN, and number of metastatic non-SNs (all P<.0001) on disease-free survival and overall survival.

CONCLUSIONS

ENE was a significant prognostic factor in patients with positive-SN melanoma. This parameter may be useful in clinical practice as a selection criterion for adjuvant treatment in patients with stage IIIA disease with a tumor burden <1 mm in the SN. We recommend its inclusion as an independent prognostic determinant in future updates of melanoma guidelines.

Three Types of Nodal Melanocytic Nevi in Sentinel Lymph Nodes of Patients With Melanoma: Pitfalls, Immunohistochemistry, and a Review of the Literature

The presence or absence of metastasis in sentinel lymph nodes often drives melanoma staging, prognosis, and treatment. However, distinguishing between metastatic melanoma cells and clusters of benign melanocytic nevus cells is not always straightforward. When morphologic hematoxylin and eosin interpretation alone is not sufficient, additional hematoxylin and eosin sections and immunohistochemical (IHC) studies may be beneficial. This review and small cases series of 3 diagnostically challenging melanocytic sentinel lymph node cases highlights the IHC approach to evaluate intraparenchymal nodal melanocytic nevi, coexistent metastatic melanoma with adjacent melanocytic nevi cells, and nodal blue nevi. In challenging cases, cytological morphology of the melanocytes, location within the lymph node, and IHC studies may assist in diagnosis. If these tools yield conflicting results, expert opinion is recommended.

A review of the AJCC melanoma staging system in the TNM classification (eighth edition)

In the eighth edition of the American Joint Committee on Cancer Staging Manual, several modifications were made for melanoma. These modifications were aimed at improving the prognosis prediction accuracy of the staging system. The main modifications are as follows: the cutoff value of the T1 category has been changed, and there are new classifications of stage IIID and of M1d (metastasis of the central nervous system). These changes will allow for more accurate stratification of melanoma prognosis. However, it is necessary to validate the new modifications through future clinical research.

Current management of melanoma patients with nodal metastases

The management of melanoma patients with nodal metastases has undergone dramatic changes over the last decade. In the past, the standard of care for patients with a positive sentinel lymph node biopsy (SLNB) was a completion lymph node dissection (CLND), while patients with palpable macroscopic nodal disease underwent a therapeutic lymphadenectomy in cases with no evidence of systemic spread. However, studies have shown that SLN metastases present as a spectrum of disease, with certain SLN-based factors being prognostic of and correlated with outcomes. Furthermore, the results of key clinical trials demonstrate that CLND provides no survival benefit over nodal observation in positive SLN patients, while other clinical trials have shown that adjuvant immune checkpoint inhibitor therapy or targeted therapy after CLND is associated with a recurrence-free survival benefit. Given the efficacy of these systemic therapies in the adjuvant setting, these agents are now being evaluated and utilized as neoadjuvant treatments in patients with regionally-localized or resectable metastatic melanoma. Multiple options now exist to treat melanoma patients with nodal disease, and determining the best treatment course for a particular case requires an in-depth knowledge of current data and an informed discussion with the patient. This review will provide an overview of the various options for treating melanoma patients with nodal metastases and will discuss the data that supported the development of these treatment options.

Nodal Recurrence is a Primary Driver of Early Relapse for Patients with Sentinel Lymph Node-Positive Melanoma in the Modern Therapeutic Era

BACKGROUND

Management of patients with sentinel lymph node (SLN)-positive melanoma has changed dramatically over the last few years such that completion lymph node dissection (CLND) has become uncommon, and many patients receive adjuvant immunotherapy or targeted therapy. This study seeks to characterize patterns and predictors of early recurrence in this setting.

PATIENTS AND METHODS

All patients with primary cutaneous melanoma undergoing sentinel lymph node biopsy (SLNB) between 3/2016 and 12/2019 were identified. The subset with a positive SLN who did not undergo CLND were examined for further analysis of outcomes and predictors of recurrence.

RESULTS

Overall, 215 patients with SLN-positive melanoma who did not have CLND were identified. Adjuvant systemic therapy was administered to 102 (47%), with 93% of this subset receiving immunotherapy (n = 95). Median follow-up from SLNB was 20 months (IQR 12-28.5 months), and 57 patients (27%) recurred during this time. The SLN basin was the most common site of recurrence (n = 38, 67% of recurrence), with isolated nodal recurrence being the most common first site of recurrent disease (n = 22, 39% of recurrence). On multivariable analysis, lymphovascular invasion (LVI) of the primary tumor, two or more involved nodes, and > 1 mm nodal deposit were independently associated with higher rates of nodal relapse.

CONCLUSIONS

Nodal recurrence is a primary driver of early disease relapse for patients with SLN-positive melanoma who do not undergo CLND in the era of effective adjuvant systemic therapy. LVI, ≥ 2 nodes, or > 1 mm nodal disease identifies patients at particularly high risk of nodal relapse.

Recent Evolution in the Management of Lymph Node Metastases in Melanoma

Introduction

Based upon two large randomized international clinical trials (German Dermatologic Cooperative Oncology Group (DeCOG-SLT) and Multicenter Selective Lymphadenectomy Trial II (MSLT-II)) published in 2016 and 2017, respectively, active surveillance has been demonstrated to have equivalent survival outcomes to completion lymphadenectomy (CLND) for a subset of patients who have microscopic lymph node disease. In this study, the changes in national practice patterns were examined regarding the utilization of CLND after positive sentinel lymph node biopsy (SLNB).

Methods

Using the National Cancer Database, CLND utilization was examined in SLN-positive patients diagnosed with melanoma between 2012 and 2016. A hierarchal logistical regression model with hospital-level random intercepts was constructed to examine the factors associated with SLNB followed by observation vs. SLNB with CLND.

Results

Of the 148,982 patients identified, 43% (n = 63,358) underwent SLNB and 10.3% (n = 6,551) had a SLNB with microscopic disease. CLND was performed for 57% (n = 2,817) of these patients. Patients were more likely to undergo CLND if they were ≤ 55 years of age (OR, 1.454; p ≤ 0.0001), ages 56 - 65 (OR, 1.127; p = 0.026), Charlson Deyo Score = 0 (OR, 2.088; p = 0.043), or were diagnosed with melanoma in 2012 (OR, 2.259, p ≤ 0.0001).

Conclusions

The utilization of CLND among patients with microscopic nodal melanoma was significantly lower in 2016 compared to 2012. Younger age, lack of comorbidities, and primary tumor location on the trunk or head/neck were associated with higher utilization of CLND.

Re-evaluation of Sentinel Lymph Node Biopsy for Melanoma

OPINION STATEMENT

The vast majority of patients newly diagnosed with melanoma present with clinically localized disease, and sentinel lymph node biopsy (SLNB) is a standard of care in the management of these patients, particularly in intermediate thickness cases, in order to provide important prognostic data. However, SLNB also has an important role in the management of patients with other subtypes of melanoma such as thick melanomas, certain thin melanomas, and specific histologic variants of melanoma such as desmoplastic melanoma. Furthermore, there have been technical advances in the SLNB technique, such as the development of newer radiotracers and use of SPECT/CT, and there is some data to suggest performing a SLNB may be therapeutic. Finally, the management of patients with a positive sentinel lymph node (SLN) has undergone dramatic changes over the past several years based on the results of recent important clinical trials. Treatment options for patients with SLN metastases now include surveillance, completion lymph node dissection, and adjuvant therapy with checkpoint inhibitors and targeted therapy. SLNB continues to play a crucial role in the management of patients with melanoma, allowing for risk stratification, potential regional disease control, and further treatment options for patients with a positive SLN.

Lymphadenectomy after a positive sentinel node biopsy in patients with cutaneous melanoma. A systematic review

Complete lymph node dissection (CLND) following a positive sentinel lymph node biopsy (SLNB) has been the standard treatment for years. However, there is increasing evidence that CLND could be omitted. Approximately 80% of patients with a positive sentinel node biopsy do not have additional nodal involvement; in these contexts, the SLNB could be diagnostic and therapeutic. However, in this group of patients, the therapeutic effect of CLND is unclear.

A systematic search was performed in EMBASE and MEDLINE (PubMed), for studies published between January 1, 2014 and December 31, 2019. Studies were included when they compared immediate CLND and observation after a positive sentinel node. The outcomes of interest were: Overall Survival (OS), melanoma-specific survival (MSS), and disease-free survival (DFS).

Eleven studies met the inclusion criteria. Two randomized clinical trials reported no differences in OS or MSS when complete lymph dissection was compared with observation alone. An increase in regional relapse was observed in the CLND group, and in one randomized controlled trial (RCT) the rate of disease-free survival was superior in those patients.

Most populations in both RCTs had low sentinel lymph node biopsy (SLNB) metastatic deposits, and head and neck melanomas were not included or underrepresented. When CNLD was omitted, an active surveillance protocol was carried out.

The evidence supports that CLND in SLNB positive patients does not confer a survival benefit. Sentinel tumor burden, localization of primary tumor, and feasibility of active surveillance should be taken into account in treatment decisions.

The sentinel node invasion level (SNIL) as a prognostic parameter in melanoma

Sentinel lymph node (SN) tumor burden is becoming increasingly important and is likely to be included in future N classifications in melanoma. Our aim was to investigate the prognostic significance of melanoma infiltration of various anatomically defined lymph node substructures. This retrospective cohort study included 1250 consecutive patients with SN biopsy. The pathology protocol required description of metastatic infiltration of each of the following lymph node substructures: intracapsular lymph vessels, subcapsular and transverse sinuses, cortex, paracortex, medulla, and capsule. Within the SN with the highest tumor burden, the SN invasion level (SNIL) was defined as follows: SNIL 1 = melanoma cells confined to intracapsular lymph vessels, subcapsular or transverse sinuses; SNIL 2 = melanoma infiltrating the cortex or paracortex; SNIL 3 = melanoma infiltrating the medulla or capsule. We classified 338 SN-positive patients according to the non-metric SNIL. Using Kaplan-Meier estimates and Cox models, recurrence-free survival (RFS), melanoma-specific survival (MSS) and nodal basin recurrence rates were analyzed. The median follow-up time was 75 months. The SNIL divided the SN-positive population into three groups with significantly different RFS, MSS, and nodal basin recurrence probabilities. The MSS of patients with SNIL 1 was virtually identical to that of SN-negative patients, whereas outgrowth of the metastasis from the parenchyma into the fibrous capsule or the medulla of the lymph node indicated a very poor prognosis. Thus, the SNIL may help to better assess the benefit-risk ratio of adjuvant therapies in patients with different SN metastasis patterns.

Predictors of Nonsentinel Lymph Node Metastasis in Cutaneous Melanoma: A Systematic Review and Meta-Analysis

BACKGROUND

Although completion lymph node dissection (CLND) is not routinely performed for a positive sentinel lymph node (SLN) anymore, adjuvant therapy depends on the risk factors available from SLN biopsy, including the risk of nonsentinel node metastases (NSNM). A systematic review and meta-analysis was performed in an attempt to identify risk factors that could be used to predict the risk of NSNM.

MATERIALS AND METHODS

Medline, Web of Science, Embase, and Cochrane were searched for articles discussing predictive factors for NSNM. PRISMA guidelines were followed, and RevMan software was used to calculate pooled odds ratios (OR) using the Mantel-Haenszel test.

RESULTS

Fifty publications were suitable for additional analysis. The clinical and primary tumor factors that were consistently identified as risk factors for NSNMs were: age >50, T stage 3 or 4, Clark level IV/V, ulceration, microsatellitosis, lymphovascular invasion, nodular histology, and extremity versus trunk primary tumor location. SLN factors that predicted NSNMs were >1 positive SLN, SLN micrometastatic tumor burden, diameter >2 mm, extracapsular extension, nonsubcapsular location (Dewar), and Rotterdam > 1 mm or ≥ 0.1 mm.

CONCLUSIONS

The findings in this study support that many clinical and pathologic risk factors that can be assessed with SLN biopsy alone can be used to predict the risk of NSNMs. The factors identified in this review should be evaluated in clinical prediction models to predict the risk of NSNMS, a prediction that may be used to select patients for adjuvant therapy in high-risk melanoma.

Challenges in sentinel node pathology in the era of adjuvant treatment

BACKGROUND

With the approval of adjuvant therapy for stage III melanoma, accurate staging is more important than ever. Sentinel node biopsy (SNB) is an accurate staging tool, yet the presence of capsular nevi (CN) can lead to a false-positive diagnosis.

PATIENTS AND METHODS

Retrospective analysis of the American Joint Committee on Cancer 7th edition stage IIIA melanoma patients who were treated at our institute between 2000 and 2015. SNB slides were reviewed for this study by an expert melanoma pathologist.

RESULTS

Of 159 eligible patients, 14 originally diagnosed with metastatic melanoma merely had CN (8.8%). Another two merely had melanophages (1.3%). Thus, 10.1% of SNs were considered false positive after revision. In 12 patients, the SN tumor burden was originally reported as larger than 1 mm but turned out to be less than 1 mm. Four patients originally reported as SN tumor burden less than 1 mm before revision turned out to have larger than 1 mm. These patients might have been over- or undertreated in the current era of adjuvant therapy for stage III melanoma.

CONCLUSIONS

Distinguishing metastatic melanoma from benign CN and melanophages can be a diagnostic challenge. We plead for an expert pathologists' review, especially when using the SNB + results to determine treatment consequences.

Clinicopathological Features, Staging, and Current Approaches to Treatment in High-Risk Resectable Melanoma

The incidence of melanoma in the United States has been increasing over the past several decades. Prognosis largely depends on disease stage, with 5-year melanoma-specific survival ranging from as high as 99% in patients with stage I disease to less than 10% for some patients with stage IV (distant metastatic) disease. Fortunately, in the last 5-10 years, there have been remarkable treatment advances for patients with high-risk resectable melanoma, including approval of targeted and immune checkpoint blockade therapies. In addition, results of recent clinical trials have confirmed the importance of sentinel lymph node biopsy and continue to refine the approach to regional lymph node basin management. Lastly, the melanoma staging system was revised in the eighth edition AJCC Cancer Staging Manual, which was implemented on January 1, 2018. Here we discuss these changes and the clinicopathological features that confer high risk for locoregional and distant disease relapse and poor survival. Implications regarding the management of melanoma in the metastatic and adjuvant settings are discussed, as are future directions for neoadjuvant therapies.

Updates in the evidence-based management of cutaneous melanoma

Treatment of cutaneous melanoma is changing with significant developments over the past several years that promise to reshape the field of melanoma surgical oncology. Modifications to the staging system based on analysis of a large international dataset, the timing and extent of regional lymphadenectomy, the emergence of effective systemic therapies in the neoadjuvant and adjuvant setting, and the role of adjuvant radiation are all undergoing a data-driven evolution. Surgeon engagement in multidisciplinary decision making remains an essential component of contemporary management for patients across all stages of melanoma and demands specific involvement of head and neck surgical oncologists.

Melanoma: Prognostic Factors and Factors Predictive of Response to Therapy

BACKGROUND

A better understanding of prognostic factors and biomarkers that predict response to treatment is required in order to further improve survival rates in patients with melanoma. Prognostic Factors: The most important histopathological factors prognostic of worse outcomes in melanoma are sentinel lymph node involvement, increased tumor thickness, ulceration and higher mitotic rate. Poorer survival may also be related to several clinical factors, including male gender, older age, axial location of the melanoma, elevated serum levels of lactate dehydrogenase and S100B. Predictive Biomarkers: Several biomarkers have been investigated as being predictive of response to melanoma therapies. For anti-Programmed Death-1(PD-1)/Programmed Death-Ligand 1 (PD-L1) checkpoint inhibitors, PD-L1 tumor expression was initially proposed to have a predictive role in response to anti-PD-1/PD-L1 treatment. However, patients without PD-L1 expression also have a survival benefit with anti-PD-1/PD-L1 therapy, meaning it cannot be used alone to select patients for treatment, in order to affirm that it could be considered a correlative, but not a predictive marker. A range of other factors have shown an association with treatment outcomes and offer potential as predictive biomarkers for immunotherapy, including immune infiltration, chemokine signatures, and tumor mutational load. However, none of these have been clinically validated as a factor for patient selection. For combined targeted therapy (BRAF and MEK inhibition), lactate dehydrogenase level and tumor burden seem to have a role in patient outcomes.

CONCLUSION

With increasing knowledge, the understanding of melanoma stage-specific prognostic features should further improve. Moreover, ongoing trials should provide increasing evidence on the best use of biomarkers to help select the most appropriate patients for tailored treatment with immunotherapies and targeted therapies.

Nodal and systemic recurrence following observation of a positive sentinel lymph node in melanoma

BACKGROUND

Two RCTs found no survival benefit for completion lymphadenectomy after positive sentinel lymph node biopsy compared with observation with ultrasound in patients with melanoma. Recurrence patterns and regional control are not well described for patients undergoing observation alone.

METHODS

All patients with a positive sentinel node biopsy who did not have immediate completion lymphadenectomy were identified from a single-institution database (1995-2018). First recurrences were classified as node only, local and in-transit (LCIT) only, LCIT and nodal, or systemic. Regional control and factors associated with recurrence survival were analysed.

RESULTS

Median follow-up was 33 months. Of 370 patients, 158 (42·7 per cent) had a recurrence. The sites of first recurrence were node only (13·2 per cent), LCIT only (11·9 per cent), LCIT and nodal (3·5 per cent), and systemic (13·8 per cent). The 3-year postrecurrence melanoma-specific survival rate was 73 (95 per cent c.i. 54 to 86) per cent for patients with node-only first recurrence, and 51 (31 to 68) per cent for those with initial systemic recurrence. In multivariable analysis, ulceration in the primary lesion (hazard ratio (HR) 2·53, 95 per cent c.i. 1·27 to 5·04), disease-free interval 12 months or less (HR 2·38, 1·28 to 4·35), and systemic (HR 2·57, 1·16 to 5·65) or LCIT and nodal (HR 2·94, 1·11 to 7·79) first recurrence were associated significantly with decreased postrecurrence survival. Maintenance of regional control required therapeutic lymphadenectomy in 13·0 per cent of patients during follow-up.

CONCLUSION

Observation after a positive sentinel lymph node biopsy is associated with good regional control, permits assessment of the time to and pattern of recurrence, and spares lymphadenectomy-related morbidity in patients with melanoma.

The EORTC-DeCOG nomogram adequately predicts outcomes of patients with sentinel node-positive melanoma without the need for completion lymph node dissection

PURPOSE

Based on recent advances in the management of patients with sentinel node (SN)-positive melanoma, we aimed to develop prediction models for recurrence, distant metastasis (DM) and overall mortality (OM).

METHODS

The derivation cohort consisted of 1080 patients with SN-positive melanoma from nine European Organization for Research and Treatment of Cancer (EORTC) centres. Prognostic factors for recurrence, DM and OM were studied with Cox regression analysis. Significant factors were incorporated in the models. Performance was assessed by discrimination (c-index) and calibration in cross-validation across centres. The models were externally validated using a prospective cohort consisting of 705 German patients with SN-positive: 473 trial participants of the German Dermatologic Cooperative Oncology Group study (DeCOG-SLT) and 232 screened patients. A nomogram was developed for graphical presentation.

RESULTS

The final model for recurrence and the calibrated models for DM and OM included ulceration, age, SN tumour burden and Breslow thickness. The models showed reasonable calibration. The c-index for the recurrence, DM and OM model was 0.68, 0.70 and 0.70, respectively, and 0.70, 0.72 and 0.74, respectively, in external validation. The EORTC-DeCOG model identified a robust low-risk group, with all identified low-risk patients (approximately 4% of the entire population) having a 5-year recurrence probability of <25% and an overall 5-year recurrence rate of 13%. A model including information on completion lymph node dissection (CLND) showed only marginal improvement in model performance.

CONCLUSIONS

The EORTC-DeCOG nomogram provides an adequate prognostic tool for patients with SN-positive melanoma, without the need for CLND. It showed consistent results across validation. The nomogram could be used for patient counselling and might aid in adjuvant therapy decision-making.

Performance of models predicting residual lymph node disease in melanoma patients following sentinel lymph node biopsy

BACKGROUND

Among melanoma patients with a tumor-positive sentinel node biopsy (SNB), approximately 20% harbor disease in non-sentinel nodes (nSN), as determined by a completion lymph node dissection (CLND). CLND lacks a survival benefit and has high morbidity. This study assesses predictive factors for nSN metastasis and validates five models predicting nSN metastasis.

METHODS

Patients with invasive melanoma were identified from the BC Cancer Agency (2005-2015). Clinicopathological data were collected from 296 patients who underwent a CLND after a positive SNB. Multivariate analysis was completed to assess predictive variables in the study population. Five models were externally validated using overall model performance (Brier score [calibration and discrimination]) and discrimination (area under the ROC curve [AUC]).

RESULTS

Seventy-three patients had nSN metastasis at the time of CLND. The variable most predictive of nSN involvement was lymphovascular invasion (odds ratio [OR] 3.99; 95% confidence interval [CI] 1.67-9.54; p = 0.002). The highest discrimination was Lee et al. (2004) (AUC 0.68 [95% CI 0.61-0.75]), Rossi et al. (2018) (AUC 0.68 [95% CI 0.57-0.77]), and Bertolli et al. (2019) (AUC 0.68 [95% CI 0.60-0.75]). Rossi et al. (2018) had the lowest overall model performance (Brier score 0.44). Rossi et al. (2018) and Bertolli et al. (2019) had the ability to stratify patients to a risk of nSN involvement up to 99% and 95%, respectively.

CONCLUSION

Bertolli et al. (2019) had amongst the highest overall model performance, was the most clinically meaningful and is recommended as the preferred model for predicting nSN metastasis.

Sentinel node tumor burden in prediction of prognosis in melanoma patients

Recent data have demonstrated no survival benefit to immediate completion lymph node dissection (CLND) for positive sentinel node (SN) disease in melanoma. It is important to identify parameters in positive SNs, which predict prognosis in melanoma patients. These might provide prognostic value in staging systems and risk models by guiding high-risk patients’ adjuvant therapy in clinical practice. In this retrospective study of university hospital melanoma database we analyzed tumor burden and prognosis in patients with positive SNs. Patients were stratified by the diameter of tumor deposit, distribution of metastatic focus in SN, ulceration and number of metastatic SNs. These were incorporated in Cox proportional hazard regression models. Predictive ability was assessed using Akaike information criterion and Harrell’s concordance index. A total of 110 patients had positive SN and 104 underwent CLND. Twenty-two (21%) patients had non-SN metastatic disease on CLND. The 5-year melanoma specific survival for CLND-negative patients was 5.00 years (IQR 3.23–5.00, range 0.72–5.00) compared to 3.69 (IQR 2.28–4.72, range 1.01–5.00) years in CLND-positive patients (HR 2.82 (95% CI 1.17–6.76, p = 0.020).The models incorporating distribution of metastatic focus and the largest tumor deposit in SN had highest predictive ability. According to Cox proportional hazard regression models, information criterions and c-index, the diameter of tumor deposit > 4 mm with multifocal location in SN despite of number of metastatic SN were the most important parameters. According to the diameter of tumor deposit and distribution of metastatic focus in SN, adequate stratification of positive SN patients was possible and risk classes for patients were identified.

Melanoma pathology reporting and staging

The pathological diagnosis of melanoma can be challenging. The provision of an appropriate biopsy and pertinent history can assist in establishing an accurate diagnosis and reliable estimate of prognosis. In their reports, pathologists should document both the criteria on which the diagnosis was based as well as important prognostic parameters. For melanoma, such prognostic parameters include tumor thickness, ulceration, mitotic rate, lymphovascular invasion, neurotropism, and tumor-infiltrating lymphocytes. Disease staging is important for risk stratifying melanoma patients into prognostic groups and patient management recommendations are often stage based. The 8th edition American Joint Committee on Cancer (AJCC) Melanoma Staging System was implemented in 2018 and several important changes were made. Tumor thickness and ulceration remain the key T category criteria. T1b melanomas were redefined as either ulcerated melanomas <1.0 mm thick or nonulcerated melanomas 0.8-1.0 mm thick. Although mitotic rate was removed as a T category criterion in the 8th edition, it remains a very important prognostic factor and should continue to be documented in primary melanoma pathology reports. It was also recommended in the 8th edition that tumor thickness be recorded to the nearest 0.1 mm (rather than the nearest 0.01 mm). In the future, incorporation of additional prognostic parameters beyond those utilized in the current version of the staging system into (web based) prognostic models/clinical tools will likely facilitate more personalized prognostic estimates. Evaluation of molecular markers of prognosis is an active area of current research; however, additional data are needed before it would be appropriate to recommend use of such tests in routine clinical practice.

Correlation of Tumor Burden in Sentinel Lymph Nodes with Tumor Burden in Nonsentinel Lymph Nodes and Survival in Cutaneous Melanoma

PURPOSE

In patients with cutaneous melanoma, metastasis in a nonsentinel lymph node (non-SLN) is a strong independent adverse prognostic factor. However, patients with a tumor-involved SLN no longer routinely undergo completion lymph node dissection (CLND). We hypothesized that SLN tumor burden may predict non-SLN tumor burden.

EXPERIMENTAL DESIGN

We compared tumor burden parameters between SLN and non-SLN in patients with cutaneous melanoma who underwent SLN biopsy with a positive SLN during 2003 to 2008 at The University of Texas MD Anderson Cancer Center.

RESULTS

We identified 336 eligible patients with a positive SLN. Of these, 308 (92%) underwent CLND, and 35 (10%) had non-SLN metastasis. The median follow-up time was 6.0 years. For patients with maximum diameter of tumor in the SLN ≤2.0 mm, >2.0-5.0 mm, and >5.0 mm, non-SLN metastasis was detected in 5 of 200 patients (3%), 10 of 63 patients (16%), and 20 of 57 patients (35%), and the mean maximum diameters of the non-SLN tumor deposits were 0.09, 1.56, and 2.71 mm, respectively (P < 0.0001). The percentage of patients with both subcapsular and intraparenchymal non-SLN tumor was higher for patients with SLN tumor in both locations than for patients with SLN tumor in only one location (P < 0.0001). Extranodal extension in a non-SLN was more common in patients with extranodal extension in an SLN (P = 0.003).

CONCLUSIONS

In patients with cutaneous melanoma who undergo CLND, SLN tumor burden predicts non-SLN tumor burden. SLN tumor burden parameters provide accurate prognostic stratification independent of non-SLN status and should be considered for incorporation into future staging systems and integrated risk models.

Final Analysis of DeCOG-SLT Trial: No Survival Benefit for Complete Lymph Node Dissection in Patients With Melanoma With Positive Sentinel Node

PURPOSE

We have previously reported on the 3-year results of the phase III German Dermatologic Cooperative Oncology Group trial (DeCOG; ClinicalTrials.gov identifier: NCT02434107) comparing distant metastasis-free survival (DMFS), recurrence-free survival (RFS), and overall survival (OS) in patients with positive sentinel lymph-node biopsy who were randomly assigned to complete lymph node dissection (CLND) or observation. Here, we report the final analysis with 72 months of median follow up.

PATIENTS AND METHODS

The multicenter randomized phase III trial included patients with cutaneous melanoma of the trunk and extremities who were randomly assigned (1:1) to undergo CLND or observation. DMFS was analyzed as the primary end point, and RFS, OS, and recurrences in the regional lymph node basin were secondary end points. The analysis was by intention to treat. Disease and survival information were collected quarterly.

RESULTS

From January 2006 to December 2014, 5,547 patients were screened to identify 1,256 with metastases in the sentinel lymph node (SLN). Of these, 483 (39%) were included: 241 in the observation arm and 242 in the CLND arm. In the final analysis, median follow up was 72 months (interquartile range, 67-77 months). No significant treatment-related difference was seen in the 5-year DMFS between the observation and CLND arms (67.6% v 64.9%, respectively; hazard ratio [HR], 1.08; P = .87). The 5-year RFS and OS also showed no difference (HR, 1.01 and 0.99, respectively). Grade 3 and 4 adverse effects occurred in 32 patients (13%) in the CLND arm; lymphedema (n = 20) and delayed wound healing (n = 5) were most common and no serious adverse events were reported.

CONCLUSION

The final results of the German Dermatologic Cooperative Oncology Group trial with a median follow up of 72 months showed higher event rates, but similar HRs compared with those at the 3-year analysis. These results confirm that immediate CLND in SLN-positive patients is not superior to observation in terms of DMFS, RFS, or OS and support not recommending CLND in patients with SLN metastasis.

The Role and Necessity of Sentinel Lymph Node Biopsy for Invasive Melanoma

Sentinel lymph node biopsy (SLNB) is a widely accepted procedure for melanoma staging and treatment. The development of lymphatic mapping and SLNB, which was first introduced in 1992, has enabled surgeons to detect microscopic nodal metastases and stage-negative regional nodal basins with low morbidity. SLNB has also facilitated the selective application of regional lymph node dissection for patients with microscopic nodal metastases, enabling unnecessary lymph node dissection. In contrast, recent major randomized phase III trials (DeCOG-SLT and MSLT–II trial) compared the clinical benefit of early completion lymph node dissection with observation after detecting microscopic nodal disease. The results of those studies indicated that there was no significant difference in the survival between the two groups, although regional control was superior after early completion lymph node dissection compared to that obtained after observation. Thus, the role and value of early completion lymph node dissection worldwide are currently very limited for patients with microscopic nodal disease. However, the use of SLNB is still controversial. In addition, the recent approval of adjuvant therapy using novel agents, such as anti-programmed death-1 antibodies, and molecular targeted therapeutics may influence the skipping of complete lymph node dissection in patients with micrometastatic nodal disease in a real-world setting. Furthermore, modern neoadjuvant therapy, which is now under investigation, may have the potential to change the surgical procedure used for nodal disease. Herein, we describe the current role and value of SLNB and completion lymph node dissection and discuss the major controversies as well as the favorable future outlook.

Impact of American Joint Committee on Cancer 8th edition classification on staging and survival of patients with melanoma

OBJECTIVE

The American Joint Committee on Cancer (AJCC) 8th staging system introduced several revisions. To assess the impact of the 8th edition American Joint Committee on Cancer (AJCC8) staging system on subgrouping and survival, patients with melanoma from two tertiary skin cancer centres were classified according to both the 7th edition American Joint Committee on Cancer (AJCC7) and AJCC8.

METHODS

A total of 1948 patients aged ≥18 years with cutaneous melanoma stage II-IV were included. The impact of sex and age on reclassification was assessed by log binomial models. The inverse probability of censoring weighting method was used to compute ROC curves from time-to-event data to assess the discriminatory ability of AJCC7 and AJCC8. Melanoma-specific survival (MSS) and overall survival (OS) were calculated, and age- and sex-adjusted MSS hazard ratios were estimated using Cox proportional hazards models.

RESULTS

Of all, 23.5% of patients were assigned a different subgroup when classified according to AJCC8. Owing to upshifting to stage IIIC (AJCC7 24.8% vs. AJCC8 50.8%), patient numbers of stages IIIA and IIIB decreased from 28.7% to 16.2% and 46.5% to 28.3%. The prediction accuracy for AJCC7 and AJCC8 was comparable (integrated time-dependent area under the curve [AUC] of 0.75 and 0.74, respectively). Five-year MSS of IIB and IIC AJCC8 was poor and lower than that of IIIA AJCC8 (80%, 67% and 89%, respectively). Compared to results of the International Melanoma Database and Discovery Platform, 5-year MSS was 10-15% points lower for stages IIC, IIIB and IIIC.

CONCLUSIONS

Upshifting affects primarily stage III subgroups, while effects in stage II are minor. Stage IIB/C (AJCC8) patients have 67-80% MSS and should be considered for adjuvant treatment, while in stage IIIA, the indication of adjuvant treatment is questionable.

Diagnostic utility of dual 5-hydroxymethylcytosine/Melan-A immunohistochemistry in differentiating nodal nevus from metastatic melanoma: An effective first-line test for the workup of sentinel lymph node specimen

BACKGROUND

Distinguishing benign nodal nevus from metastatic melanoma can be diagnostically challenging, with important clinical consequences. Recently, the loss of epigenetic marker, 5-hydroxymethylcytosine (5-hmC) expression by immunohistochemistry has been found in melanomas and atypical melanocytic neoplasms.

METHODS

About 41 metastatic melanomas and 20 nodal nevi were retrieved. Nuclear 5-hmC (brown) and cytoplasmic Melan-A Red (red) double immunohistochemical staining was performed.

RESULTS

Total or partial loss of nuclear expression of 5-hmC was noted in 40/41 metastatic melanomas; these tumor cells were strongly positive for Melan-A Red, except in one case of desmoplastic melanoma. All cases of nodal nevus showed uniformly retained nuclear expression of 5-hmC accompanied by strong Melan-A Red cytoplasmic staining. In two cases containing both nodal nevus and metastatic melanoma, all tumor cells were positive for Melan-A Red, but a nuclear expression of 5-hmC was selectively absent only in the melanoma tumor cells.

CONCLUSION

Dual 5-hmC/Melan-A Red immunohistochemistry is highly specific in distinguishing nodal nevus from metastatic melanoma. Our protocol for brown and red chromogens used in this study provides excellent color contrast and is easy to interpret. Furthermore, this dual staining method allows the preservation of limited tumor tissue, which could be used for potential molecular studies.

Meta-analysis of completion lymph node dissection in sentinel lymph node-positive melanoma

BACKGROUND

The role of completion lymph node dissection (CLND) in patients with sentinel lymph node (SLN)-positive melanoma continues to be debated. This systematic review and meta-analysis evaluated survival and recurrence rate in these patients who underwent CLND, compared with observation.

METHODS

A comprehensive MEDLINE and Embase database search was performed for cohort studies and RCTs published between January 2000 and June 2017 that assessed the outcomes of CLND compared with observation in patients with SLN-positive melanoma. The primary outcome was survival and the secondary outcome was recurrence rate. Studies were assessed for quality using the Cochrane risk-of-bias tool for RCTs and Newcastle-Ottawa Scale for cohort studies. Pooled relative risk or hazard ratio with 95 per cent confidence intervals were calculated for each outcome. The extent of heterogeneity between studies was assessed with the I² test. The protocol was registered in PROSPERO (CRD42017070152).

RESULTS

Fifteen studies (13 cohort studies with 7868 patients and 2 RCTs with 2228 patients) were identified for qualitative synthesis. Thirteen studies remained for quantitative meta-analysis. Survival was similar in patients who underwent CLND and those who were observed (risk ratio (RR) for death 0·85, 95 per cent c.i. 0·71 to 1·02). The recurrence rate was also similar (RR 0·91, 0·79 to 1·05).

CONCLUSION

Patients with SLN-positive melanoma do not have a significant benefit in survival or recurrence rate if they undergo CLND rather than observation.

Malignant melanoma: Claims and controversies

Malignant melanoma is a common cancer in young people and its incidence is rising in the UK. The management of the disease is evolving, with new approaches to the treatment of locally advanced and systemic disease in particular being rapidly developed. Sentinel node biopsy is a valuable treatment option for the staging of melanoma, and completion lymphadenectomy in node-positive patients improves local disease control. However, early clearance of occult microscopic nodal disease has not been proven to confer a melanoma-specific survival advantage. Delays in the diagnosis and treatment of melanoma lead to claims being brought in negligence, but establishing causation in such cases can be difficult.