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

A Narrative Review of Current Knowledge on Cutaneous Melanoma

Cutaneous melanoma is a public health problem. Efforts to reduce its incidence have failed, as it continues to increase. In recent years, many risk factors have been identified. Numerous diagnostic systems exist that greatly assist in early clinical diagnosis. The histopathological aspect illustrates the grim nature of these cancers. Currently, pathogenic pathways and the tumor microclimate are key to the development of therapeutic methods. Revolutionary therapies like targeted therapy and immune checkpoint inhibitors are starting to replace traditional therapeutic methods. Targeted therapy aims at a specific molecule in the pathogenic chain to block it, stopping cell growth and dissemination. The main function of immune checkpoint inhibitors is to boost cellular immunity in order to combat cancer cells. Unfortunately, these therapies have different rates of effectiveness and side effects, and cannot be applied to all patients. These shortcomings are the basis of increased incidence and mortality rates. This study covers all stages of the evolutionary sequence of melanoma. With all these data in front of us, we see the need for new research efforts directed at therapies that will bring greater benefits in terms of patient survival and prognosis, with fewer adverse effects.

The role of sentinel node tumor burden in modeling the prognosis of melanoma patients with positive sentinel node biopsy: an Italian melanoma intergroup study (N = 2,086)

Background

The management of melanoma patients with metastatic melanoma in the sentinel nodes (SN) is evolving based on the results of trials questioning the impact of completion lymph node dissection (CLND) and demonstrating the efficacy of new adjuvant treatments. In this landscape, new prognostic tools for fine risk stratification are eagerly sought to optimize the therapeutic path of these patients.

Methods

A retrospective cohort of 2,086 patients treated with CLND after a positive SN biopsy in thirteen Italian Melanoma Centers was reviewed. Overall survival (OS) was the outcome of interest; included independent variables were the following: age, gender, primary melanoma site, Breslow thickness, ulceration, sentinel node tumor burden (SNTB), number of positive SN, non-sentinel lymph nodes (NSN) status. Univariate and multivariate survival analyses were performed using the Cox proportional hazard regression model.

Results

The 3-year, 5-year and 10-year OS rates were 79%, 70% and 54%, respectively. At univariate analysis, all variables, except for primary melanoma body site, were found to be statistically significant prognostic factors. Multivariate Cox regression analysis indicated that older age (P < 0.0001), male gender (P = 0.04), increasing Breslow thickness (P < 0.0001), presence of ulceration (P = 0.004), SNTB size (P < 0.0001) and metastatic NSN (P < 0.0001) were independent negative predictors of OS.

Conclusion

The above results were utilized to build a nomogram in order to ease the practical implementation of our prognostic model, which might improve treatment personalization.

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.

HMB45/PRAME, a Novel Double Staining for the Diagnosis of Melanocytic Neoplasms: Technical Aspects, Results, and Comparison With Other Commercially Available Staining (PRAME and Melan A/PRAME)

PRAME (PReferentially expressed Antigen in MElanoma) is a tumor-associated antigen that was recently found to be expressed by malignant melanocytic lesions but not by benign ones, thus resulting useful in this diagnostic field. PRAME could also be expressed by some normal tissues and nonmelanocytic tumors, suggesting as caution should be adopted to use PRAME as a "pan-melanoma" marker for the differential diagnosis with other malignant tumors. Until now, PRAME expression was exclusively investigated through single staining with a monoclonal antibody targeting PRAME and with double staining for Melan A/PRAME found to be useful in specific diagnostic sets. Herein, we studied the expression of PRAME in 40 melanocytic lesions and 23 nonmelanocytic ones using PRAME, Melan A/PRAME, and novel double staining for HMB45/PRAME. Although our results need to be validated, they support the adoption of HMB45/PRAME, alone or in combination with PRAME and Melan A/PRAME, as a helpful marker in the diagnosis of melanocytic neoplasms with a high concordance rate between primary melanoma and corresponding metastases.

Impact of the changes in the completion lymph node dissection criteria and approval of adjuvant therapies on the real-world outcomes of Japanese stage III melanoma patients

BACKGROUND

Completion lymph node dissection (CLND) has long been the standard treatment for stage III melanomas identified as metastasis on the sentinel node (SN-positive). Two major changes occurred in 2017 and 2018, the change in the CLND criteria for SN-positive patients and the approval of several adjuvant therapies could revolutionize such management approach. However, their effects have not been fully investigated on the real-world outcomes of stage III melanoma patients. Therefore, we investigated the impact of these changes on the prognosis of Japanese stage III melanoma patients.

METHODS

Totally, 119 stage III, SN-positive melanoma patients were included. They were categorized into those diagnosed as SN-positive between January 2015 and June 2017 (pre-June 2017 group) and between July 2017 and December 2019 (post-July 2017 group). Recurrence-free survival (RFS), overall survival, and prognostic factors were analyzed.

RESULTS

The frequency of patients who received CLND was significantly higher in the pre-June 2017 group (p = 0.001), and those who received adjuvant therapy were significantly higher in the post-July 2017 group (p < 0.001). The 2-year RFS was 50.1% and 68.5% in the pre-June and post-July 2017 groups, respectively (p = 0.049). Cox proportional hazards model analysis for RFS showed that adjuvant therapies reduce the risk of recurrence (hazard ratio 0.37; 95% confidence interval 0.14-0.99; p = 0.047).

CONCLUSION

Changes in the CLND criteria in SN-positive patients and the approval of adjuvant therapies for stage III melanomas have significantly impacted Japanese melanoma medicine. Adjuvant therapy tended to prolong patient's RFS while omitting immediate CLND had no significant negative influence on it.

Histopathologic and Molecular Diagnosis of Melanoma

Conventional histopathology is the primary means of melanoma diagnosis. Both architectural and cytologic features aid in discrimination of melanocytic nevi from melanoma. Communication between the clinician and pathologist regarding the history, examination, differential diagnosis, prior biopsy findings, method of sampling, and specimen orientation is critical to an accurate diagnosis. A melanoma pathology report includes multiple prognostic indicators to guide surgical and medical management. In challenging cases, immunohistochemistry and molecular diagnostics may be of benefit.

Tumor-draining lymph nodes: At the crossroads of metastasis and immunity

Early engagement of the lymphatic system by solid tumors in peripheral, nonlymphoid tissues is a clinical hallmark of cancer and often forecasts poor prognosis. The significance of lymph node metastasis for distant spread, however, has been questioned by large-scale lymph node dissection trials and the likely prevalence of direct hematogenous metastasis. Still, an emerging appreciation for the immunological role of the tumor-draining lymph node has renewed interest in its basic biology, role in metastatic progression, antitumor immunity, and patient outcomes. In this review, we discuss our current understanding of the early mechanisms through which tumors engage lymphatic transport and condition tumor-draining lymph nodes, the significance of these changes for both metastasis and immunity, and potential implications of the tumor-draining lymph node for immunotherapy.

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.

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.

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 prognostic significance of non-sentinel lymph node metastasis in cutaneous and acral melanoma patients-A multicenter retrospective study

Background

Whether non‐sentinel lymph node (SLN)‐positive melanoma patients can benefit from completion lymph node dissection (CLND) is still unclear. The current study was performed to identify the prognostic role of non‐SLN status in SLN‐positive melanoma and to investigate the predictive factors of non‐SLN metastasis in acral and cutaneous melanoma patients.

Methods

The records of 328 SLN‐positive melanoma patients who underwent radical surgery at four cancer centers from September 2009 to August 2017 were reviewed. Clinicopathological data including age, gender, Clark level, Breslow index, ulceration, the number of positive SLNs, non‐SLN status, and adjuvant therapy were included for survival analyses. Patients were followed up until death or June 30, 2019. Multivariable logistic regression modeling was performed to identify factors associated with non‐SLN positivity. Log‐rank analysis and Cox regression analysis were used to identify the prognostic factors for disease‐free survival (DFS) and overall survival (OS).

Results

Among all enrolled patients, 220 (67.1%) had acral melanoma and 108 (32.9%) had cutaneous melanoma. The 5‐year DFS and OS rate of the entire cohort was 31.5% and 54.1%, respectively. More than 1 positive SLNs were found in 123 (37.5%) patients. Positive non‐SLNs were found in 99 (30.2%) patients. Patients with positive non‐SLNs had significantly worse DFS and OS (log‐rank P < 0.001). Non‐SLN status (P = 0.003), number of positive SLNs (P = 0.016), and adjuvant therapy (P = 0.025) were independent prognostic factors for DFS, while non‐SLN status (P = 0.002), the Breslow index (P = 0.027), Clark level (P = 0.006), ulceration (P = 0.004), number of positive SLNs (P = 0.001), and adjuvant therapy (P = 0.007) were independent prognostic factors for OS. The Breslow index (P = 0.020), Clark level (P = 0.012), and number of positive SLNs (P = 0.031) were independently related to positive non‐SLNs and could be used to develop more personalized surgical strategy.

Conclusions

Non‐SLN‐positive melanoma patients had worse DFS and OS even after immediate CLND than those with non‐SLN‐negative melanoma. The Breslow index, Clark level, and number of positive SLNs were independent predictive factors for non‐SLN status.

Management of the positive sentinel lymph node in the post-MSLT-II era

BACKGROUND AND OBJECTIVES

The publication of MSLT-II shifted recommendations for management of sentinel lymph node biopsy positive (SLNB+) melanoma to favor active surveillance. We examined trends in immediate completion lymph node dissection (CLND) following publication of MSLT-II.

METHODS

Using a prospective melanoma database at a high-volume center, we identified a cohort of consecutive SLNB+ patients from July 2016 to April 2019. Patient and disease characteristics were analyzed with multivariate logistic regression to examine factors associated with CLND.

RESULTS

Two hundred and thirty-five patients were included for analysis. CLND rates were 67%, 33%, and 26% for the year before, year after, and second-year following MSLT-II. Factors associated with undergoing CLND included primary located in the head and neck (59% vs 33%, P = .003 and odds ratio [OR], 5.22, P = .002) and higher sentinel node tumor burden (43% vs 10% for tumor burden ≥0.1 mm, P < .001 and OR, 8.64, P = .002).

CONCLUSIONS

Rates of CLND in SLNB+ melanoma decreased dramatically, albeit not uniformly, following MSLT-II. Factors that increased the likelihood of immediate CLND were primary tumor located in the head and neck and high sentinel node tumor burden. These groups were underrepresented in MSLT-II, suggesting that clinicians are wary of implementing active surveillance recommendations for patients perceived as higher risk.

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.