The amount of metastatic melanoma in a sentinel lymph node: does it have prognostic significance?

Stage III Melanoma: A Proposed Staging Model That Outperforms the American Joint Committee on Cancer Eighth Edition Staging System

National Comprehensive Cancer Network guidelines state that clinical stage III melanoma patients may undergo ultrasound surveillance of the nodal basin in lieu of complete lymph node dissection (CLND). This has led to an inability to accurately classify patients according to the American Joint Committee on Cancer (AJCC) eighth edition staging system because it uses the total number of positive lymph nodes from the CLND to assign a pathologic N stage. We propose a new model for clinical stage III melanoma patients that does not rely on the total number of positive lymph nodes. Instead, it uses Breslow depth, ulceration status, sentinel lymph node metastasis size, and extracapsular extension to stratify patients into groups 1 to 4. We compared our model's ability to predict melanoma-specific survival (MSS), distant metastasis-free survival (DMFS) and locoregional recurrence, and distant metastasis-free survival (DMFS-LRFS) to the current AJCC system with and without CLND-data using a Cox proportional hazards model and Akaike Information Criteria weights. Although not reaching our predetermined level of statistical significance of 95%, our model was 5 times more likely to better predict MSS compared with the AJCC model with CLND. In addition, our model was significantly better than the AJCC model without CLND in predicting MSS. Our model performed significantly better than the AJCC model in predicting DMFS and DMFS-LRFS regardless of whether data from CLND were included.

Validation study on the 2 mm diameter cutoff in lymph node-positive cases following radical prostatectomy in accordance with the AJCC/UICC TNM 8th edition: Real-world data analysis from a Japanese cohort

OBJECTIVES

The American Joint Committee on Cancer (AJCC)/Union for International Cancer Control (UICC) 8th edition has proposed micrometastasis as a lymph node metastasis (LN+) of diameter ≤2 mm in prostate cancer. However, supporting evidence has not described. We evaluated LN+ patients' survival after radical prostatectomy (RP) based on the LN maximum tumor diameter (MTD).

METHODS

Data from 561 LN+ patients after RP and pelvic LN dissection (PLND) treated between 2006 and 2019 at 33 institutions were retrospectively investigated. Patients were stratified by a LN+ MTD cutoff of 2 mm. Outcomes included castration resistance-free survival (CRFS), metastasis-free survival (MFS), cancer-specific survival (CSS), and overall survival (OS).

RESULTS

In total, 282 patients were divided into two groups (LN+ MTD >2 mm [n = 206] and ≤2 mm [n = 76]). Patients of LN+ status >2 mm exhibited significantly decreased CRFS and MFS, and poorer CSS and OS. No patients developed CRPC in the LN+ status ≤2 mm group when the PLND number was ≥14. Multivariate analysis showed the number of LN removed, RP Gleason pattern 5, and MTD in LN+ significantly predicted CRFS.

CONCLUSIONS

Patients of LN+ status ≤2 mm showed better prognoses after RP. In all the patients in the ≤2-mm group, the progression to CRPC could be prevented with appropriate interventions, particularly when PLND is performed accurately. Our findings support the utility of the pN substaging proposed by the AJCC/UICC 8th edition; this will facilitate precision medicine for patients with advanced prostate cancer.

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.

Nonvisualized sentinel node on preoperative lymphoscintigraphy in primary cutaneous melanoma: an 11-year retrospective survey

BACKGROUND

Sentinel lymph node (SLN) biopsy in cutaneous melanoma patients evaluates the regional draining basin for occult micrometastatic disease. Occasionally, nonidentification of SLN impairs the acquisition of this important prognostic factor.

OBJECTIVES

To investigate the outcomes of melanoma patients with negative lymphoscintigraphic findings and patients who underwent SLN biopsy from 2004 to 2015 ( n  = 1200) were retrospectively reviewed for tumor characteristics and clinical outcomes.

METHODS

Patients with nonvisualized lymph nodes (NV group) who underwent only preoperative lymphoscintigraphy were separated and compared with a cohort drawn from all melanoma patients who completed the surgical procedure within the same period (V group).

RESULTS

A negative lymphoscintigraphic scan was observed in 38 cases (3.2% of all patients). The NV group showed a significantly older age (median 66.0 vs. 48.3 years; P  < 0.0001). Head and neck melanomas were more frequent in the NV group compared to the control group (25.1 vs. 7.8%; P  = 0.009). Tumor characteristics such as ulceration and Breslow thickness do not influence the lymphoscintigraphy result. No differences were found in overall survival (OS) and disease-free survival (DFS) between the groups.

CONCLUSIONS

The nonvisualization of regional lymph nodes by lymphoscintigraphy is more frequent in older patients with head and neck melanomas. From the clinical point of view, no specific recommendation emerged for patients' management because the nonvisualization of the SLN did not show a significant influence on DFS and OS rates. However, lack of knowledge of lymph node status suggests performing a tighter follow-up eventually by ultrasound evaluation of all potential lymph node drainage basins.

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.

Does It Really Pay-Off? Comparison of Lymphadenectomy versus Observational Approach in Skin Melanoma with Positive Sentinel Node Biopsy: Systematic Review and Meta-Analysis

The aim of this meta-analysis was to answer the question as to whether performing CLND (complete lymph node dissection) is necessary in every case of the melanoma patient after the positive SNB (sentinel node biopsy). To resolve doubts the authors reanalyzed previous articles and systematized the knowledge about the concerning medical problem. The databases such as PubMed, Scopus and Web of Science were screened to find articles that will be helpful to answer the controversial question if performing lymphadenectomy is crucial. The inclusion criteria consisted of randomized clinical trials, comparison of lymphadenectomy versus observation and positive sentinel node biopsy. After which, seven articles were examined. Authors analyzed parameters such as: recurrence, 3-year survival and 5-year survival. There was no relationship between the performance of CLND and melanoma recurrence (OR 1.04; 95% CI: 0.82–1.31; p = 0.75). However, no CLND group had higher 3-year survival (OR 1.22; 95% CI: 1.03–1.44; p = 0.02) and 5-year survival (OR 1.30; 95% CI: 1.19–1.85; p = 0.008). In conclusion, the observational approach to the melanoma patients with positive sentinel node biopsy is associated with comparable or slightly improved 3- and 5-year survival, then in case of routine lymphadenectomy. Although, in each melanoma patient a decision to perform or withhold lymphadenectomy should always be considered individually. Patients with low perioperative risk could be considered for surgical approach. The study was registered in PROSPERO and was assigned with the unique identifying number “CRD42021241272”.

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.

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.

Picomets: Assessing single and few cell metastases in melanoma sentinel lymph node biopsies

BACKGROUND

Lymph node involvement is a significant prognostic factor for melanoma. Both number of positive nodes and disease burden within a lymph node affects survival. However, the significance of few tumor cells within a single node and subsequent optimal management remains without consensus. We investigated the implications of minimal nodal disease on clinical outcomes.

METHODS

We reviewed 752 patients who underwent lymph node sampling at time of primary melanoma resection at our institution over 15 years. We deemed patients who had 1 node with 1 to 4 atypical cells staining positive for either Melan-A or Sox-10 as having "picomets." We examined the initial clinicopathological features, subsequent management, and outcomes.

RESULTS

Thirty-three patients (4%) met criteria for having picomets. The most common number of positively staining atypical cells was 1 (n = 13). Nodal staging at initial pathology review varied, and overall stage ranged from IA to IIIC. Four patients underwent further therapy, none of whom had recurrent disease. Of the 29 patients undergoing observation/surveillance only, 5 had disease recurrence (17%).

CONCLUSION

Although patients with picomets had better outcomes than historical stage matched cohorts, a small subset had recurrent disease. Staging patients with picomets as "N0" may not reflect the true negative prognostic significance of picomets. A larger population of patients meeting picomets criteria is needed to draw further conclusions.

Tumor cells, rather than dendritic cells, deliver antigen to the lymph node for cross-presentation

It is widely accepted that generation of tumor specific CD8+ T-cell responses occur via cross-priming; however the source of tumor antigen for this event is unknown. We examined the source and form of tumor antigen required for cross-presentation in the local lymph node (LN) using a syngeneic mouse tumor model expressing a marker antigen. We found that cross-presentation of this model tumor antigen in the LN is dependent on continuous traffic of antigen from the tumor site, but without any detectable migration of tumor resident dendritic cells (DCs). Instead, small numbers of tumor cells metastasize to local LNs where they are exposed to a localized CTL attack, resulting in delivery of tumor antigen into the cross-presentation pathway.

Evolving management of positive regional lymph nodes in melanoma: Past, present and future directions

Sentinel lymph node (SLN) biopsy has become the standard of care for lymph node staging in melanoma and the most important predictor of survival in clinically node-negative disease. Previous guidelines recommend completion lymph node dissection (CLND) in cases of positive SLN; however, the lymph nodes recovered during CLND are only positive in a minority of these cases. Recent evidence suggests that conservative management (i.e. observation) has similar outcomes compared to CLND. We sought to review the most current literature regarding the management of SLN in metastatic melanoma and to discuss potential future directions.

Lymphatic Mapping and Sentinel Lymph Node Biopsy in the Management of Primary Cutaneous Melanoma: Report of a Single-centre Experience

Aims and Background

Lymphatic mapping and sentinel lymph node biopsy provide important prognostic data in patients with early stage melanoma and are crucial in guiding the management of the tumor. We report our experience with lymphatic mapping and sentinel lymph node biopsy in a group of patients with primary cutaneous melanoma and discuss recent concepts and controversies on its use.

Patients and Methods

A total of 111 patients with stage I-II AJCC primary cutaneous melanoma underwent lymphatic mapping and sentinel lymph node biopsy from December 1999 through December 2004 using a standardized technique of preoperative lymphoscintigraphy and biopsy guided by blue dye injection in addition to a hand-held gamma probe. After removal, sentinel lymph nodes were submitted to serial sectioning and permanent preparations for histological and immunohistochemical examination. Complete lymph node dissection was performed only in patients with tumor-positive sentinel lymph nodes.

Results

Sentinel lymph nodes were identified and removed in all patients (detection rate of 100%), and metastases were found in 17 cases (15.3%). The incidence of metastasis in sentinel lymph nodes was 2.1%, 15.9%, 35.2%, and 41.6% for melanomas < or 1.0, 1.01-2.0, 2.01-4.0, and > 4.0 mm in thickness, respectively. Complete lymph node dissection was performed in 15 of 17 patients with positive sentinel lymph nodes, and metastases in non-sentinel lymph nodes were detected in only 2 cases (11.7%). Recurrences were more frequently observed in patients with a positive than in those with negative sentinel lymph node (41.1% vs 5.3% at a median follow-up of 31.5 months, P<0.001). The false-negative rate was 2.1%.

Conclusions

Our study confirms that lymphatic mapping and sentinel lymph node biopsy allow accurate staging and yield relevant prognostic information in patients with early stage melanoma.

The Role of Completion Lymphadenectomy in Positive Regional Lymph Nodes in Melanoma: A Meta-analysis

BACKGROUND

The optimal management of melanoma with positive sentinel lymph node (SLN) remains unclear. Completion lymph node dissection (CLND) only yields additional positive non-SLN in 20% of cases and its benefits on survival remains debatable.

METHODS

An online database search of Medline was performed; key bibliographies were reviewed. Studies comparing outcomes after CLND versus observation were included. Odds ratios (ORs) with the corresponding 95% confidence intervals (CIs) by random fixed effects models of pooled data were calculated. The primary endpoints were disease-free survival (DFS), melanoma-specific survival (MSS), and overall survival (OS).

RESULTS

Search strategy yielded 117 publications. Twelve studies were selected for inclusion, comprising 7966 SLN-positive patients. Among these patients, 5306 (66.6%) subjects underwent CLND and 2660 (33.4%) patients were observed. Median Breslow thickness and ulceration were similar between groups (2.8 ± 0.6 mm versus 2.5 ± 0.8 mm, P = 0.721; and 38.8% versus 37.2%, P = 0.136, CLND versus observation, respectively). CLND was associated with statistically significant improved 3-y (71.0% versus 66.2%, OR 0.82, 95% CI 0.69-0.97, P = 0.02) and 5-y DFS (48.3% versus 47.8%, OR 0.75, 95% CI 0.59-0.96, P = 0.02) compared with observation. However, no difference was demonstrated in 3-y MSS (83.7% versus 84.7%, OR 1.09, 95% CI 0.88-1.35, P = 0.41), 5-y MSS (68.4% versus 69.8%, OR 1.02, 95% CI 0.88-1.19, P = 0.78), or OS (68.2% versus 78.9%, OR 0.93, 95% CI 0.55-1.57, P = 0.78).

CONCLUSIONS

Based on this large-scale analysis, CLND improved both 3- and 5-y DFS, possibly because of increased rates of local control; however, this did not translate in improved MSS or OS. Efforts toward the identification of molecular markers associated with poor outcomes in SLN-positive patients who undergo observation are warranted.

Histological immune response patterns in sentinel lymph nodes involved by metastatic melanoma and prognostic significance

BACKGROUND

To further characterize the micromorphometric immunological pattern to metastatic melanoma in sentinel lymph node (SLN) biopsies and completion lymph node (CLN) dissections and their relation to 5-year overall survival (OS).

METHODS

Retrospective cohort of 49 patients from 1996 to 2005 with a positive SLN who underwent CLN dissection (CLD) was studied. Micromorphometric characteristics included follicular center count (FCC)/profile, sinus histiocytosis, metastatic size, tumor infiltrating lymphocytes (intranodal), paracortical dendritic cells, germinal center reaction and morphology. Comparison of Kaplan-Meier survival curves used the exact log-rank statistic.

RESULTS

In the high-FCC (n = 5-51) vs the low-FCC (n < 5) lymph nodes, a delayed separation occurred at 3 years, with 5-year OS rates being 73% vs 54% in the high- and low-FCC groups, respectively. Improved survival up to 3 years was also noted in CLDs that showed a higher FCC when compared to the prior SLN. Patients with metastatic deposits >2 mm had significantly lower 5-year survival (both <.001).

CONCLUSIONS

Nodal micromorphometric features (ie, FCC) are probably related to host immune response to metastasis. Quantitative evaluation of lymphoid follicular centers could provide valuable prognostic information to help to stratify patients.

Metastases of malignant neoplasms: Historical, biological, & clinical considerations

The metastasis of neoplastic cells from their site of origin to distant anatomic locations continues to be the principal cause of death from malignant tumors, and that fact has been recognized by physicians for over a century. After the work done by Halsted in the treatment of breast cancer in the 1880s, accepted surgical canon held that metastasis occurred in a linear fashion, with centrifugal "growth in continuity" from the primary neoplasm that first involved regional lymph nodes. Those structures were considered to then be the sources of more distant, visceral metastases. With that premise in mind, radical and "ultra-radical" surgical procedures were devised to remove as many lymph nodes as possible in the treatment of carcinomas and melanomas. However, such interventions were ineffective in altering tumor-related mortality. This review considers the details of the historical material just mentioned. It also reviews currently-held concepts on biological mechanisms of metastasis, the "sentinel" lymph node biopsy technique, and the important topic of metastatic tumor "dormancy" as the cause of surgical treatment failure. Finally, predictive models of tumor behavior are discussed, which are based on gene signatures. These will likely be the key to identifying malignant lesions of low surgical stage that ultimately prove fatal through later manifestation of metastasis.

Hyaluronidase To Enhance Nanoparticle-Based Photodynamic Tumor Therapy

Photodynamic therapy (PDT) is considered as a safe and selective way to treat a wide range of cancers as well as nononcological disorders. However, as oxygen is required in the process of PDT, the hypoxic tumor microenvironment has largely limited the efficacy of PDT to treat tumors especially those with relatively large sizes. To this end, we uncover that hyaluronidase (HAase), which breaks down hyaluronan, a major component of extracellular matrix (ECM) in tumors, would be able to enhance the efficacy of nanoparticle-based PDT for in vivo cancer treatment. It is found that the administration of HAase would lead to the increase of tumor vessel densities and effective vascular areas, resulting in increased perfusion inside the tumor. As a result, the tumor uptake of nanomicelles covalently linked with chlorine e6 (NM-Ce6) would be increased by ∼2 folds due to the improved "enhanced permeability and retention" (EPR) effect, while the tumor oxygenation level also shows a remarkable increase, effectively relieving the hypoxia state inside the tumor. Those effects taken together offer significant benefits in greatly improving the efficacy of PDT delivered by nanoparticles. Taking advantage of the effective migration of HAase from the primary tumor to its drainage sentinel lymph nodes (SLNs), we further demonstrate that this strategy would be helpful to the treatment of metastatic lymph nodes by nanoparticle-based PDT. Lastly, both enhanced EPR effect of NM-Ce6 and relieved hypoxia state of tumor are also observed after systemic injection of modified HAase, proving its potential for clinical translation. Therefore, our work presents a new concept to improve the efficacy of nanomedicine by modulating the tumor microenvironment.

Micrometastatic cancer cells in lymph nodes, bone marrow, and blood: Clinical significance and biologic implications

Cancer metastasis may be regarded as a progressive process from its inception in the primary tumor microenvironment to distant sites by way of the lymphovascular system. Although this type of tumor dissemination often occurs in an orderly fashion via the sentinel lymph node (SLN), acting as a possible gateway to the regional lymph nodes, bone marrow, and peripheral blood and ultimately to distant metastatic sites, this is not a general rule as tumor cells may enter the blood and spread to distant sites, bypassing the SLN. Methods of detecting micrometastatic cancer cells in the SLN, bone marrow, and peripheral blood of patients have been established. Patients with cancer cells in their SLN, bone marrow, or peripheral blood have worse clinical outcomes than patients with no evidence of spread to these compartments. The presence of these cells also has important biologic implications for disease progression and the clinician's understanding of the process of cancer metastasis. Further characterization of these micrometastatic cancer cells at each stage and site of metastasis is needed to design novel selective therapies for a more "personalized" treatment.

Comparison of sentinel lymph node micrometastatic tumor burden measurements in melanoma

BACKGROUND

Multiple methods have been proposed to classify the micrometastatic tumor burden in sentinel lymph nodes (SLN) for melanoma. The purpose of this study was to determine the classification scheme that best predicts nonsentinel node (NSN) metastasis, disease-free survival (DFS), and overall survival (OS).

STUDY DESIGN

A single reviewer reanalyzed tumor-positive SLN from a multicenter, prospective clinical trial of patients with melanoma ≥ 1.0 mm Breslow thickness who underwent SLN biopsy. The following micrometastatic disease burden measurements were recorded: Starz classification, Dewar classification (microanatomic location), maximum diameter of the largest focus of metastasis, maximum tumor area, and sum of all diameters. Univariate and multivariate models and Kaplan-Meier analysis were used to evaluate each classification system.

RESULTS

We reviewed 204 tumor-positive SLNs from 157 patients. On univariate analysis, all criteria except Starz classification were statistically significant risk factors for NSN metastasis. On multivariate analysis, including Breslow thickness, ulceration, age, sex, and NSN status, maximum diameter (using a cut-off of 3 mm) was the only classification system that was an independent risk factor predicting DFS (hazard ratio 2.31, p = 0.0181) and OS (hazard ratio 3.53, p = 0.0005). By Kaplan-Meier analysis, DFS and OS were significantly different among groups using maximum diameter cut-offs of 1 and 3 mm.

CONCLUSIONS

Maximum tumor diameter outperformed other measurements of metastatic tumor burden, including microanatomic tumor location (Dewar classification), Starz classification, maximum tumor area, and sum of all diameters for prediction of survival. Maximum tumor diameter is a simple method of assessing micrometastatic tumor burden that should be reported routinely.

Is complete lymph node dissection after a positive sentinel lymph node biopsy for cutaneous melanoma always necessary? A meta-analysis

BACKGROUND

The current recommendation for patients with cutaneous melanoma and a positive sentinel lymph node (SLN) biopsy is a complete lymph node dissection (CLND). However, metastatic melanoma is not present in approximately 80% of CLND specimens. A meta-analysis was performed to identify the clinicopathological variables most predictive of non-sentinel node (NSN) metastases when the sentinel node is positive in patients with melanoma.

METHODS

A systematic search was conducted using MEDLINE, PubMed, EMBASE, Current Contents Connect, Cochrane library, Google scholar, Science Direct, and Web of Science. The search identified 54 relevant articles reporting the frequency of NSN metastases in melanoma. Original data was abstracted from each study and used to calculate a pooled odds ratio (OR) and 95% confidence interval (95% CI).

FINDINGS

The pooled estimates that were found to be significantly associated with the high likelihood of NSN metastases were: ulceration (OR: 1.88, 95% CI: 1.53-2.31), satellitosis (OR: 3.25, 95% CI: 1.86-5.66), neurotropism (OR: 2.51, 95% CI: 1.39-4.53), >1 positive SLN (OR: 1.77, 95% CI: 1.2-2.62), Starz 3 (old) (OR: 1.83, 95% CI: 0.89-3.76), Angiolymphatic invasion (OR: 2.46, 95% CI: 1.34-4.54), extensive location (OR: 2.22, 95% CI: 1.74-2.81), macrometastases >2 mm (OR: 1.95, 95% CI: 1.61-2.35), extranodal extension (OR: 3.38, 95% CI: 1.79-6.40) and capsular involvement (OR: 3.16, 95% CI: 1.37-7.27). There were 3 characteristics not associated with NSN metastases: subcapsular location (OR: 0.51, 95% CI: 0.38-0.67), Rotterdam Criteria <0.1 mm (OR: 0.29, 95% CI: 0.17-0.50) and Starz I (new) (OR: 0.44, 95% CI: 0.22-0.91). Other variables including gender, Breslow thickness 2-4 mm and extremity as primary site were found to be equivocal.

INTERPRETATION

This meta-analysis provides evidence that patients with low SLN tumor burden could probably be spared the morbidity associated with CLND. We identified 9 factors predictive of non-SLN metastases that should be recorded and evaluated routinely in SLN databases. However, further studies are needed to confirm the standard criteria for not performing CLND.

Role of high-resolution ultrasound and PET/CT imaging for preoperative characterization of sentinel lymph nodes in cutaneous melanoma

The purpose of our study was the comparison of high-resolution ultrasound (HRUS) and positron emission tomography combined with computerised tomography (PET/CT) in the preoperative characterization and identification of subclinical nodal metastases focusing on sentinel lymph nodes (SLN) in melanoma patients. Patients with cutaneous melanoma (CM) who received sentinel lymph node biopsy at the Department of Dermatology and Allergy, University of Bonn, between January 2009 and January 2011 had been evaluated with a retrospective computer-aided search concerning preoperative staging procedures. A combination of PET/CT and HRUS had been performed preoperatively in 20 of 123 patients. A total of 59 SLNs had been removed in those 20 patients followed by histopathologic examination. HRUS correctly identified two of 17 positive SLNs whereas PET/CT imaging identified none. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of HRUS were 11.8 % (95 % confidence interval [CI] = 3.3-34.3), 100 % (95 % CI = 91.6-100.0), 100.0 % (95 % CI = 34.2-100.0), and 73.7 % (95 % CI = 61.0-83.3), respectively. On the basis of this limited study cohort, HRUS had a better value than PET/CT in preoperative identification of positive SLNs, suggesting a possible diagnostic superiority of HRUS in general characterization of peripheral nodal disease in CM.

Inguinal or inguino-iliac/obturator lymph node dissection after positive inguinal sentinel lymph node in patients with cutaneous melanoma

Background

The aim of the study was to determine whether the presence of inguinal sentinel lymph node (SLN) metastases smaller than 2 mm (micrometastases) subdivided according to the number of micrometastases predicts additional, non-sentinel inguinal, iliac or obturator lymph node involvement in completion lymph node dissection (CLND).

Patients and methods.

Positive inguinal SLN was detected in 58 patients (32 female, 26 male, median age 55 years) from 743 consecutive and prospectively enrolled patients with primary cutaneous melanoma stage I and II who were treated with SLN biopsy between 2001 and 2007.

Results

Micrometastases in inguinal SLN were detected in 32 patients, 14 were single, 2 were double, and 16 were multiple. Twenty-six patients had macrometastases.

Conclusions

No patient with any micrometastases or a single SLN macrometastasis in the inguinal region had any iliac/obturator non-sentinel metastases after CLND in our series. Furthermore, no patient with single SLN micrometastasis in the inguinal region had any non-sentinel metastases at all after CLND in our series. In these cases respective CLND might be omitted.

Diversity of stage III melanoma in the era of sentinel lymph node biopsy

BACKGROUND

Sentinel lymph node (SLN) biopsy for melanoma often detects minimal nodal tumor burden. Although all node-positive patients are considered stage III, there is controversy regarding the necessity of adjuvant therapy for all patients with tumor-positive SLN.

METHODS

Post hoc analysis was performed of a prospective multi-institutional study of patients with melanoma ≥ 1.0 mm Breslow thickness. All patients underwent SLN biopsy; completion lymphadenectomy was performed for patients with SLN metastasis. Kaplan-Meier analysis of disease-free survival (DFS) and overall survival (OS) was performed. Univariate and multivariate Cox regression analyses were performed. Classification and regression tree (CART) analysis also was performed.

RESULTS

A total of 509 patients with tumor-positive SLN were evaluated. Independent risk factors for worse OS included thickness, age, gender, presence of ulceration, and tumor-positive non-SLN (nodal metastasis found on completion lymphadenectomy). As the number of tumor-positive SLN and the total number of tumor-positive nodes (SLN and non-SLN) increased, DFS and OS worsened on Kaplan-Meier analysis. On CART analysis, the 5-year OS rates ranged from 84.9% (women with thickness < 2.1 mm, age < 59 years, no ulceration, and tumor-negative non-SLN) to 14.3% (men with thickness ≥ 2.1 mm, age ≥ 59 years, ulceration present, and tumor-positive non-SLN). Six distinct subgroups were identified with 5-year OS in excess of 70%.

CONCLUSIONS

Stage III melanoma in the era of SLN is associated with a very wide range of prognosis. CART analysis of prognostic factors allows discrimination of low-risk subgroups for which adjuvant therapy may not be warranted.

Progression of cutaneous melanoma: implications for treatment

The survival rates of melanoma, like any type of cancer, become worse with advancing stage. Spectrum theory is most consistent with the progression of melanoma from the primary site to the in-transit locations, regional or sentinel lymph nodes and beyond to the distant sites. Therefore, early diagnosis and surgical treatment before its spread is the most effective treatment. Recently, new approaches have revolutionized the diagnosis and treatment of melanoma. Genomic profiling and sequencing will form the basis for molecular taxonomy for more accurate subgrouping of melanoma patients in the future. New insights of molecular mechanisms of metastasis are summarized in this review article. Sentinel lymph node biopsy has become a standard of care for staging primary melanoma without the need for a more morbid complete regional lymph node dissection. With recent developments in molecular biology and genomics, novel molecular targeted therapy is being developed through clinical trials.

Sentinel lymph nodes containing very small (<0.1 mm) deposits of metastatic melanoma cannot be safely regarded as tumor-negative

BACKGROUND

Some authors have suggested that patients with very small (<0.1 mm) deposits of metastatic melanoma in sentinel lymph nodes (SLNs) should be considered SLN-negative, whereas others have reported that such patients can have adverse long-term outcomes. The aims of the present study were to determine whether extensive sectioning of SLNs resulted in more accurate categorization of histologic features of tumor deposits and to assess prognostic associations of histologic parameters obtained using more intensive sectioning protocols.

METHODS

From patients with a single primary cutaneous melanoma who underwent SLN biopsy between 1991 and 2008, those in which the maximum size of the largest tumor deposit (MaxSize) in SLNs was <0.1 mm in the original sections were identified. Five batches of additional sections were cut from the SLN tissue blocks at intervals of 250 μm. The 1st batch was cut from the blocks without any trimming; these sections were therefore immediately adjacent to the original sections. Each batch included 5 sequential sections, the 1st and 5th stained with hematoxylin-eosin, and the 2nd, 3rd, and 4th stained immunohistochemically with S-100, HMB-45, and Melan-A, respectively. In each batch of sections, the following histologic features of tumor deposit(s) in the SLNs were evaluated: MaxSize; tumor penetrative depth (TPD) (defined as the maximum depth of tumor deposit(s) from the inner margin of the lymph node capsule), and intranodal location (classified as subcapsular if the tumor deposit(s) were confined to the subcapsular zone or parenchymal if there was any involvement of the nodal parenchyma beyond the subcapsular zone). The measured histologic parameters were compared in each batch of sections. The association of histologic parameters with overall survival was assessed for the parameters measured in each batch of sections.

RESULTS

There were 20 eligible patients (15 females, 5 males, median age 60 years). After a median follow-up duration of 40 months, 4 patients had died from melanoma and 2 patients of unknown causes. Completion lymph node dissection (CLND) was performed in 13 cases (65%) and was negative in all cases. Relative to the measured values on the original sections, all 3 parameters were upstaged in subsequent batches of sections, but no further upstaging of MaxSize, TPD, or location was seen beyond batch 3, batch 4, and batch 2, respectively. Increasing MaxSize was associated with significantly poorer overall survival in batches 1, 2, and 3. Parenchymal involvement was significantly associated with poorer survival in batches 2-5. TPD was not significantly associated with overall survival.

CONCLUSIONS

The results of this study indicate that very small (<0.1 mm) deposits of melanoma in SLNs may be associated with adverse clinical outcomes and that this is due, at least in part, to the underestimation of SLN tumor burden in the initial sections. Our evidence does not support clinical decision-making on the assumption that patients with very small melanoma deposits in SLNs have the same outcome as those who are SLN-negative.

The impact of primary melanoma thickness and microscopic tumor burden in sentinel lymph nodes on melanoma patient survival

BACKGROUND

The primary objectives of this work are to (1) quantitate tumor burden in sentinel lymph nodes (SLNs), and (2) assess the independent contributions of SLN tumor burden and primary melanoma thickness (PMT) with respect to progression-free survival (PFS) and overall survival (OS).

METHODS

Sixty-three patients (41 male and 22 female) with one or more positive SLNs were available for review in this study, with median follow-up of 6.8 years. PMT was measured and SLN metastases were assessed for size, as maximum metastasis size (MMS) in mm, by hematoxylin and eosin (H&E) and immunohistochemistry (S100 and HMB45). PFS and OS were calculated from time of SLN resection until melanoma recurrence or death. Univariate and multivariate analyses and trend test were performed.

RESULTS

Kaplan-Meier estimates of PFS and OS differed significantly by MMS (log-rank P = 0.031 for PFS and P = 0.016 for OS) and PMT (log-rank P = 0.036 for PFS and P < 0.001 for OS). After adjusting for age and gender, the hazard ratio (HR) associated with MMS was 1.09 per mm increase (P = 0.05) for PFS, and 6.30 (P = 0.014) and 5.41 (P = 0.048) for OS in patients, respectively, with MMS of 0.6-5.5 mm and MMS ≥5.5 mm compared with those with MMS <0.6 mm. When patients were stratified by their tumor characteristics of PMT, the risk for disease progression and worse OS was substantially higher for the group with PMT ≥ 4.5 mm (HR = 13.10 and P = 0.022 for PFS; HR = 17.26 and P < 0.001 for OS) relative to the baseline group with PMT <1.6 mm. All patients had completion lymph node dissection (CLND) except for four patients. Patients with positive CLND (14, 22.2%) showed significant worse PFS (P = 0.002) and OS (P = 0.0003) than the negative CLND group (45, 71.4%).

CONCLUSIONS

PMT and MMS were independently prognostic of PFS and OS in melanoma patients. Patients with negative CLND had significantly better PFS and OS than those with positive CLND.

Impact of nodal status and tumor burden in sentinel lymph nodes on the clinical outcomes of cancer patients

The validation of sentinel lymph node (SLN) concept in melanoma and breast cancer has established a new paradigm in cancer metastasis that, in general, cancer cells spread in a orderly fashion from the primary site to the SLNs in the regional nodal basin and then to the distant sites. In this review article, we examine the development of SLN concept in penile carcinoma, melanoma and breast carcinoma and its application to other solid cancers with emphasis of the relationship between micrometastasis in SLNs and clinical outcomes.

Analysis of predictive factors for the outcome of complete lymph node dissection in melanoma patients with metastatic sentinel lymph nodes

BACKGROUND

Sentinel lymph node biopsy (SLNB) is a widely accepted procedure to accurately stage patients with melanoma. However, there is no consensus concerning the practical consequences of a positive SLN, since a survival benefit of a complete lymph node dissection (CLND) has not yet been demonstrated.

OBJECTIVE

We wondered whether we could identify a subgroup of patients with metastatic involvement of the SLN who could be excluded from the recommendation to undergo CLND.

METHODS

At the Department of Dermatology at the University of Munich, a total of 213 patients with metastatic SLNs (24.9%) were identified among 854 patients who had undergone SLNB between 1996 and 2007. All SLN-positive patients had been advised to have CLND. Survival analyses were performed by using the Kaplan-Meier approach.

RESULTS

A total of 176 (82.6%) of 213 SLN-positive patients underwent CLND. In this group, 26 patients (14.8%) showed metastatic disease in non-sentinel lymph nodes (NSLN). The 5-year overall survival (OS) was 26.1% in NSLN-positive patients and 74% in NSLN-negative patients. SLN-positive patients who refused CLND had a better prognosis than patients with CLND. Breslow tumor thickness was significantly associated with positive CLND status with higher median values in CLND-positive than CLND-negative patients (3.03 vs 2.22 mm).

LIMITATIONS

The subgroup of patients with metastatic disease in CLND may have been too small to reach statistical significance for other tumor- or patient-related parameters. Mitotic indices of the primary melanomas had not been determined in this retrospective study; thus a possible correlation with lymph node status could not be tested.

CONCLUSION

Among SLN-positive patients, the presence of metastatic NSLN is a highly significant poor prognostic factor. Tumor thickness is a significant prognostic parameter for positive CLND status and might be considered in the decision to perform CLND in case of metastatic SLN.

Molecular analysis of melanoma-induced sentinel lymph node immune dysfunction

INTRODUCTION

Sentinel lymph nodes (SLNs) of melanoma patients show evidence of tumor-induced immune dysfunction. Our previous works have shown that IL-10 and IFNγ co-regulate indoleamine-2,3-dioxygenase (IDO)-expressing immunosuppressive dendritic cells (DCs) in melanoma SLNs. The goal of this study is to examine the relationship between melanoma SLN tumor burden and the degree of SLN immune dysfunction as a model to study tumor-induced immune dysfunction. We hypothesize that SLN tumor burden correlates with the degree of SLN immune dysfunction.

METHODS

Patients undergoing SLN biopsy for clinical stages I and II melanomas were enrolled in the study under an IRB-approved protocol. During the SLN biopsy, non-hot and non-blue portion of the SLN was harvested, flash-frozen in liquid nitrogen, and mRNA was extracted. By using quantitative real-time PCR, gene expressions of cytokines (IL-4, IL-10, IFNγ, TGFβ, GM-CSF) and the surrogates of immunosuppressive regulatory and effector cells (IDO-expressing DCs and Foxp3-expressing T-regs, respectively) were measured and correlated against the SLN tumor burden (MART1) and against each other. The data were log transformed for normalization. Statistical test used Student's t-test and stepwise multivariate regression analysis. Statistical significance was determined at P < 0.05.

RESULTS

SLNs of 74 patients were analyzed in this analysis. Ten of seventy-four patients (13.5%) had tumor-positive SLNs. MART1 gene expression showed a significant difference between the SLN (+) and SLN (-) groups (P = 0.04). Among the various cytokines, multivariate analysis showed that only IFNγ gene expression correlated independently with MART1 gene expression (P < 0.0001, r = 0.91). Similar multivariate analyses show that IFNγ (P < 0.0001, r = 0.78), IL-10 (P = 0.0037, r = 0.60), and TGFβ (P < 0.0001, r = 0.95) gene expressions correlated independently with IDO gene expression. IFNγ (P < 0.0001, r = 0.87) and GM-CSF (P = 0.042, r = 0.76) gene expressions correlated independently with Foxp3 gene expression. MART1 gene expression showed independent correlation with IDO (P = 0.0002, r = 0.75) and Foxp3 (P = 0.0002, r = 0.75) gene expressions.

CONCLUSION

SLN tumor burden correlates with immunosuppressive IDO and Foxp3 expressions within the SLNs of melanoma patients. Our data are consistent with our theory that melanoma induces expressions of specific cytokines, which in turn, stimulate immune suppressors within the SLN. This study also supports our previous finding that IL-10 and IFNγ co-regulate IDO within the SLN. In our data, IFNγ is the sole cytokine that correlates with the SLN tumor burden and seems to play a central role in tumor-induced immunological changes in the SLN immune microenvironment.

Prognosis in patients with sentinel node-positive melanoma is accurately defined by the combined Rotterdam tumor load and Dewar topography criteria

PURPOSE

Prognosis in patients with sentinel node (SN)-positive melanoma correlates with several characteristics of the metastases in the SN such as size and site. These factors reflect biologic behavior and may separate out patients who may or may not need additional locoregional and/or systemic therapy.

PATIENTS AND METHODS

Between 1993 and 2008, 1,080 patients (509 women and 571 men) were diagnosed with tumor burden in the SN in nine European Organisation for Research and Treatment of Cancer (EORTC) melanoma group centers. In total, 1,009 patients (93%) underwent completion lymph node dissection (CLND). Median Breslow thickness was 3.00 mm. The median follow-up time was 37 months. Tumor load and tumor site were reclassified in all nodes by the Rotterdam criteria for size and in 88% by the Dewar criteria for topography.

RESULTS

Patients with submicrometastases (< 0.1 mm in diameter) were shown to have an estimated 5-year overall survival rate of 91% and a low nonsentinel node (NSN) positivity rate of 9%. This is comparable to the rate in SN-negative patients. The strongest predictive parameter for NSN positivity and prognostic parameter for survival was the Rotterdam-Dewar Combined (RDC) criteria. Patients with submicrometastases that were present in the subcapsular area only, had an NSN positivity rate of 2% and an estimated 5- and 10-year melanoma-specific survival (MSS) of 95%.

CONCLUSION

Patients with metastases < 0.1 mm, especially when present in the subcapsular area only, may be overtreated by a routine CLND and have an MSS that is indistinguishable from that of SN-negative patients. Thus the RDC criteria provide a rational basis for decision making in the absence of conclusions provided by randomized controlled trials.

Contrast-enhanced ultrasound: a filter role in AJCC stage I/II melanoma patients

One of the most significant advances in melanoma staging is sentinel lymph node biopsy (SLNB). It is a surgical technique to detect occult nonpalpable micrometastases in regional lymph nodes. Recently, contrast-enhanced ultrasound (CEUS) was introduced as a noninvasive procedure, in spite of SLNB, for the detection of SLNs in patients with cutaneous melanoma. The main purpose of this study was to evaluate the diagnostic accuracy of CEUS in the diagnostic workup of patients with melanoma in comparison with the final histology of SLNs detected through preoperative lymphoscintigraphy. Fifteen patients with cutaneous melanoma underwent prompt excisional biopsy with narrow margins in order to avoid impairment of the melanoma lymphatic basin and were referred for SLNB according to routine indications between January and February 2009. In our study CEUS showed, albeit based on a small patient sample, a negative predictive value of 100%, that means that all negative results were confirmed by negative SLN histopathological examination; all ultrasonographically negative lymph nodes corresponded to nonmetastatic sentinel nodes.