Clark level risk stratifies patients with mitogenic thin melanomas for sentinel lymph node biopsy

Predictors of sentinel lymph node metastasis in very thin invasive melanomas

BACKGROUND

Melanomas < 0.8 mm in Breslow depth have less than a 5% risk for nodal positivity. Nonetheless, nodal positivity is prognostic for this group. Early identification of nodal positivity may improve the outcomes for these patients.

OBJECTIVES

To determine the degree to which ulceration and other high-risk features predict sentinel lymph node (SLN) positivity for very thin melanomas.

METHODS

The National Cancer Database was reviewed from 2012 to 2018 for patients with melanoma with Breslow thickness < 0.8 mm. Data were analysed from 7 July 2022 through to 25 February 2023. Patients were excluded if data regarding their ulceration status or SLN biopsy (SLNB) performance were unknown. We analysed patient, tumour and health system factors for their effect on SLN positivity. Data were analysed using χ2 tests and logistic regressions. Overall survival (OS) was compared by Kaplan-Meier analyses.

RESULTS

Positive nodal metastases were seen in 876 (5.0%) patients who underwent SLNB (17 692). Factors significantly associated with nodal positivity on multivariable analysis include lymphovascular invasion [odds ratio (OR) 4.5, P < 0.001], ulceration (OR 2.6, P < 0.001), mitoses (OR 2.1, P < 0.001) and nodular subtype (OR 2.1, P < 0.001). Five-year OS was 75% and 92% for patients with positive and negative SLN, respectively.

CONCLUSIONS

Nodal positivity has prognostic significance for very thin melanomas. In our cohort, the rate of nodal positivity was 5% overall in these patients who underwent SLNB. Specific tumour factors (e.g. lymphovascular invasion, ulceration, mitoses, nodular subtype) were associated with higher rates of SLN metastases and should be used to guide clinicians in choosing which patients will benefit from SLNB.

Invasive Cutaneous Melanoma: Evaluating the Prognostic Significance of Some Parameters Associated with Lymph Node Metastases

Background and Objectives: This study aimed to assess the clinical-pathological profile of patients with invasive cutaneous melanomas and to identify the parameters with a prognostic role in the lymph nodal spread of this malignant tumor. Materials and Methods: We performed a retrospective study on patients with invasive cutaneous melanomas who underwent surgery in the "Pius Brînzeu" County Clinical Emergency Hospital from Timișoara, Romania, and were evaluated for the status of loco-regional lymph nodes. We selected and analyzed some parameters searching for their relationship with lymph node metastases. Results: We identified 79 patients with invasive cutaneous melanomas (29 men and 50 women, mean age 59.36 years). A percentage of 58.3% of melanomas had Breslow tumor thickness >2 mm; 69.6% of melanomas showed a Clark level IV-V. Tumor ulceration was present in 59.5% of melanomas. A mitotic rate of ≥5 mitoses/mm² was observed in 48.1% of melanomas. Tumor-infiltrating lymphocytes (TILs), non-brisk, were present in 59.5% of cases and 22.8% of patients had satellite/in-transit metastasis (SINTM). Tumor regression was identified in 44.3% of cases. Lymph nodes metastases were found in 43.1% of patients. Statistical analysis showed that lymph node metastases were more frequent in melanomas with Breslow thickness >2 mm (p = 0.0002), high Clark level (p = 0.0026), mitotic rate >5 mitoses/mm² (p = 0.0044), ulceration (p = 0.0107), lymphovascular invasion (p = 0.0182), SINTM (p = 0.0302), and non-brisk TILs (p = 0.0302). Conclusions: The Breslow thickness >2 mm, high Clark level, high mitotic rate and ulceration are the most important prognostic factors for lymph nodal spread in cutaneous melanomas. However, some melanomas without these clinical-pathological features can have an unexpected, aggressive evolution, which entails the necessity of close and prolonged clinical follow-up of patients, including those with lesions considered without risk.

The Evolution of the Sentinel Node Biopsy in Melanoma

The growing repertoire of approved immune-checkpoint inhibitors and targeted therapy has revolutionized the adjuvant treatment of melanoma. While the treatment of primary cutaneous melanoma remains wide local excision (WLE), the management of regional lymph nodes continues to evolve in light of practice-changing clinical trials and dramatically improved adjuvant therapy. With large multicenter studies reporting no benefit in overall survival for completion lymph node dissection (CLND) after a positive sentinel node biopsy (SLNB), controversy remains regarding patient selection and clinical decision-making. This review explores the evolution of the SLNB in cutaneous melanoma in the context of a rapidly changing adjuvant treatment landscape, summarizing the key clinical trials which shaped current practice guidelines.

Sentinel lymph node biopsy in patients with T1a cutaneous malignant melanoma: A multicenter cohort study

BACKGROUND

Sentinel lymph node biopsy is not routinely recommended for T1a cutaneous melanoma due to the overall low risk of positivity. Prognostic factors for positive sentinel lymph node (SLN⁺) in this population are poorly characterized.

OBJECTIVE

To determine factors associated with SLN⁺ in patients with T1a melanoma.

METHODS

Patients with pathologic T1a (<0.80 mm, nonulcerated) cutaneous melanoma from 5 high-volume melanoma centers from 2001 to 2020 who underwent wide local excision with sentinel lymph node biopsy were included in the study. Patient and tumor characteristics associated with SLN⁺ were analyzed by univariate and multivariable logistic regression analyses. Age was dichotomized into ≤42 (25% quartile cutoff) and >42 years.

RESULTS

Of the 965 patients identified, the overall SLN⁺ was 4.4% (N = 43). Factors associated with SLN⁺ were age ≤42 years (7.5% vs 3.7%; odds ratio [OR], 2.14; P = .03), head/neck primary tumor location (9.2% vs 4%; OR, 2.75; P = .04), lymphovascular invasion (21.4% vs 4.2%; OR, 5.64; P = .01), and ≥2 mitoses/mm² (8.2% vs 3.4%; OR, 2.31; P = .03). Patients <42 years with ≥2 mitoses/mm² (N = 38) had a SLN⁺ rate of 18.4%.

LIMITATIONS

Retrospective study.

CONCLUSION

SLN⁺ is low in patients with T1a melanomas, but younger age, lymphovascular invasion, mitogenicity, and head/neck primary site appear to confer a higher risk of SLN⁺.

Predictive Values of Pathological and Clinical Risk Factors for Positivity of Sentinel Lymph Node Biopsy in Thin Melanoma: A Systematic Review and Meta-Analysis

Background

The indications for sentinel lymph node biopsy (SLNB) for thin melanoma are still unclear. This meta-analysis aims to determine the positive rate of SLNB in thin melanoma and to summarize the predictive value of different high-risk features for positive results of SLNB.

Methods

Four databases were searched for literature on SLNB performed in patients with thin melanoma published between January 2000 and December 2020. The overall positive rate and positive rate of each high-risk feature were calculated and obtained with 95% confidence intervals (CIs). Both unadjusted odds ratios (ORs) and adjusted ORs (AORs) of high-risk features were analyzed. Pooled effects were estimated using random-effects model meta-analyses.

Results

Sixty-six studies reporting 38,844 patients with thin melanoma who underwent SLNB met the inclusion criteria. The pooled positive rate of SLNB was 5.1% [95% confidence interval (CI) 4.9%-5.3%]. Features significantly predicted a positive result of SLNB were thickness≥0.8 mm [AOR 1.94 (95%CI 1.28-2.95); positive rate 7.0% (95%CI 6.0-8.0%)]; ulceration [AOR 3.09 (95%CI 1.75-5.44); positive rate 4.2% (95%CI 1.8-7.2%)]; mitosis rate >0/mm2 [AOR 1.63 (95%CI 1.13-2.36); positive rate 7.7% (95%CI 6.3-9.1%)]; microsatellites [OR 3.8 (95%CI 1.38-10.47); positive rate 16.6% (95%CI 2.4-36.6%)]; and vertical growth phase [OR 2.76 (95%CI 1.72-4.43); positive rate 8.1% (95%CI 6.3-10.1%)].

Conclusions

The overall positive rate of SLNB in thin melanoma was 5.1%. The strongest predictor for SLN positivity identified was microsatellites on unadjusted analysis and ulceration on adjusted analysis. Breslow thickness ≥0.8 mm and mitosis rate >0/mm² both predict SLN positivity in adjusted analysis and increase the positive rate to 7.0% and 7.7%. We suggest patients with thin melanoma with the above high-risk features should be considered for giving an SLNB.

Compliance with sentinel lymph node biopsy guidelines for invasive melanomas treated with Mohs micrographic surgery

BACKGROUND

Sentinel lymph node biopsy (SLNB) has not been studied for invasive melanomas treated with Mohs micrographic surgery using frozen-section MART-1 immunohistochemical stains (MMS-IHC). The primary objective of this study was to assess the accuracy and compliance with National Comprehensive Cancer Network (NCCN) guidelines for SLNB in a cohort of patients who had invasive melanoma treated with MMS-IHC.

METHODS

This retrospective cohort study included all patients who had primary, invasive, cutaneous melanomas treated with MMS-IHC at a single academic center between March 2006 and April 2018. The primary outcomes were the rates of documenting discussion and performing SLNB in patients who were eligible based on NCCN guidelines. Secondary outcomes were the rate of identifying the sentinel lymph node and the percentage of positive lymph nodes.

RESULTS

In total, 667 primary, invasive, cutaneous melanomas (American Joint Committee on Cancer T1a-T4b) were treated with MMS-IHC. The median patient age was 69 years (range, 25-101 years). Ninety-two percent of tumors were located on specialty sites (head and/or neck, hands and/or feet, pretibial leg). Discussion of SLNB was documented for 162 of 176 (92%) SLNB-eligible patients, including 127 of 127 (100%) who had melanomas with a Breslow depth >1 mm. SLNB was performed in 109 of 176 (62%) SLNB-eligible patients, including 102 of 158 melanomas (65%) that met NCCN criteria to discuss and offer SLNB and 7 of 18 melanomas (39%) that met criteria to discuss and consider SLNB. The sentinel lymph node was successfully identified in 98 of 109 patients (90%) and was positive in 6 of those 98 patients (6%).

CONCLUSIONS

Combining SLNB and MMS-IHC allows full pathologic staging and confirmation of clear microscopic margins before reconstruction of specialty site invasive melanomas. SLNB can be performed accurately and in compliance with consensus guidelines in patients with melanoma using MMS-IHC.

Use and Costs of Sentinel Lymph Node Biopsy in Non-Ulcerated T1b Melanoma: Analysis of a Population-Based Registry

BACKGROUND

The utility of sentinel lymph node biopsy (SLNB) for non-ulcerated T1b melanoma is debated and associated costs are poorly characterized. Prior work using institutional registries may overestimate the incidence of nodal positivity in this population.

OBJECTIVE

The aim of this study was to estimate the use of SLNB, positivity prevalence, and procedural costs in patients with non-ulcerated T1b melanoma using a population-based registry.

METHODS

We identified patients with clinically node-negative, non-ulcerated melanoma 0.8-1.0 mm thick (T1b according to the 8th edition standard of the American Joint Committee on Cancer) in the Surveillance, Epidemiology, and End Results database from 2010 to 2016. The prevalence of SLNB procedures and positive sentinel nodes were calculated. Factors associated with SLNB and sentinel node positivity were assessed using logistic regression. Medicare reimbursement costs and patient out-of-pocket expenses for SLNB and wide local excision (WLE) versus WLE alone were estimated.

RESULTS

Among 7245 included patients, 3835(53%) underwent SLNB, 156 (4.1%, 95% confidence interval 3.5-4.7) of whom had a positive SLNB. Younger age, >1 mitosis per mm², female sex, and truncal tumor location were associated with higher odds of positivity. The estimated SLNB cost to identify one patient with stage III disease was $71,700 (range $54,648-$83,172). Out-of-pocket expenses for a Medicare patient were estimated to be $652 for a WLE and SLNB and $79 for a WLE alone.

CONCLUSIONS

In this population-based study, only 4% of selected non-ulcerated T1b patients had a positive SLNB, which is lower than prior reports. At the population level, SLNB is associated with high costs per prognostic information gained.

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.

ESMO consensus conference recommendations on the management of locoregional melanoma: under the auspices of the ESMO Guidelines Committee

The European Society for Medical Oncology (ESMO) held a consensus conference on melanoma on 5-7 September 2019 in Amsterdam, The Netherlands. The conference included a multidisciplinary panel of 32 leading experts in the management of melanoma. The aim of the conference was to develop recommendations on topics that are not covered in detail in the current ESMO Clinical Practice Guideline and where available evidence is either limited or conflicting. The main topics identified for discussion were: (i) the management of locoregional disease; (ii) targeted versus immunotherapies in the adjuvant setting; (iii) targeted versus immunotherapies for the first-line treatment of metastatic melanoma; (iv) when to stop immunotherapy or targeted therapy in the metastatic setting; and (v) systemic versus local treatment of brain metastases. The expert panel was divided into five working groups in order to each address questions relating to one of the five topics outlined above. Relevant scientific literature was reviewed in advance. Recommendations were developed by the working groups and then presented to the entire panel for further discussion and amendment before voting. This manuscript presents the results relating to the management of locoregional melanoma, including findings from the expert panel discussions, consensus recommendations and a summary of evidence supporting each recommendation. All participants approved the final manuscript.

Sentinel Lymph Node Biopsy for T1b Melanoma: Balancing Prognostic Value and Cost

BACKGROUND

The purpose of this study is to report the additional prognostic information and cost associated with sentinel lymph node biopsy (SLNB) for patients with T1b melanoma.

PATIENTS AND METHODS

An institutional database was queried for patients with T1b melanoma (0.8-1.0 mm or < 0.8 mm with ulceration) with at least 5 years of follow-up. Results of SLNB, completion lymphadenectomy (CLND), recurrence, and melanoma-specific survival (MSS) were assessed. Institutional costs of melanoma care were converted to Medicare proportional dollars. A Markov model was created to estimate long-term costs.

RESULTS

Among the total 392 patients, 238 underwent SLNB. Median follow-up was 10.5 years. SLNB was positive in 19 patients (8.0%). Patients who underwent SLNB had higher 10-year nodal recurrence-free survival (98.6% vs. 91.2%, p < 0.001) but not MSS (94.4% vs. 93.2%, p = 0.55). Ulceration (HR 4.7, p = 0.022) and positive sentinel node (HR 11.5, p < 0.001) were associated with worse MSS. Estimates for 5-year costs reflect a fourfold increase in total costs of care associated with SLNB. However, a treatment plan that forgoes adjuvant therapy for resected stage IIIA melanoma but offers systemic therapy for a node-basin recurrence would nullify the additional cost of SLNB.

CONCLUSIONS

SLNB is prognostic for T1b melanoma. Its impact on the overall cost of melanoma care is intimately tied to systemic therapy in the adjuvant and recurrent settings.

Surgical Management of Lymph Nodes in Melanoma

This article provides a comprehensive evaluation of surgical management of the lymph node basin in melanoma, with historical, anatomic, and evidence-based recommendations for practice.

A nomogram to predict node positivity in patients with thin melanomas helps inform shared patient decision making

OBJECTIVE

To develop a nomogram to estimate the probability of positive sentinel lymph node (+SLN) for patients with thin melanoma and to characterize its potential impact on sentinel lymph node biopsy (SLNB) rates.

METHODS

Patients diagnosed with thin (0.5-1.0 mm) melanoma were identified from the National Cancer Database 2012 to 2015. A multivariable logistic regression model was used to examine factors associated with +SLN, and a nomogram to predict +SLN was constructed. Nomogram performance was evaluated and diagnostic test statistics were calculated.

RESULTS

Of the 21 971 patients included 10 108 (46.0%) underwent SLNB, with a 4.0% +SLN rate. On multivariable analysis, age, Breslow thickness, lymphovascular invasion, ulceration, and Clark level were significantly associated with SLN status. The area under the receiver operating curve was 0.67 (95% confidence interval, 0.65-0.70). While 15 249 (69.4%) patients had either T1b tumors or T1a tumors with at least one adverse feature, only 2846 (13.0%) had a nomogram predicted probability of a +SLN ≥5%. Using this cut-off, the indication for a SLNB in these patients would be reduced by 81.3% as compared to the American Joint Committee on Cancer 8th edition staging criteria.

CONCLUSIONS

The risk predictions obtained from the nomogram allow for more accurate selection of patients who could benefit from SLNB.

Survival analysis and sentinel lymph node status in thin cutaneous melanoma: A multicenter observational study

Mitotic rate is no longer considered a staging criterion for thin melanoma in the 8th edition of the American Joint Committee on Cancer Staging Manual. The aim of this observational study was to identify prognostic factors for thin melanoma and predictors and prognostic significance of sentinel lymph node (SLN) involvement in a large multicenter cohort of patients with melanoma from nine tertiary care hospitals. A total of 4249 consecutive patients with thin melanoma diagnosed from January 1, 1998 to December 31, 2016 were included. The main outcomes were disease-free interval and melanoma-specific survival for the overall population and predictors of SLN metastasis (n = 1083). Associations between survival and SLN status and different clinical and pathologic variables (sex, age, tumor location, mitosis, ulceration, regression, lymphovascular invasion, histologic subtype, Clark level, and Breslow thickness) were analyzed by Cox proportional hazards regression and logistic regression. SLN status was the most important prognostic factor for melanoma-specific survival (hazard ratio, 13.8; 95% CI, 6.1-31.2; P < 0.001), followed by sex, ulceration, and Clark level for patients who underwent SLNB. A mitotic rate of >2 mitoses/mm2 was the only factor associated with a positive SLN biopsy (odds ratio, 2.9; 95% CI, 1.22-7; P = 0.01. SLN status is the most important prognostic factor in thin melanoma. A high mitotic rate is associated with metastatic SLN involvement. SLN biopsy should be discussed and recommended in patients with thin melanoma and a high mitotic rate.

Predictors of sentinel lymph node positivity in thin melanoma using the National Cancer Database

BACKGROUND

Sentinel lymph node biopsy (SLNB) specimens are often obtained from patients for further staging after these patients have undergone melanoma excision. Limited data regarding predictors of SLNB positivity in thin melanoma are available.

OBJECTIVE

We sought to evaluate predictors of SLNB positivity in thin melanoma.

METHODS

Patients with cutaneous melanoma with a Breslow thickness ≤1.00 mm who received a SLNB were identified from the National Cancer Database between 2004 and 2014 (n = 9186). Predictors of SLNB positivity were analyzed using logistic regression.

RESULTS

In a multivariate analysis, patients <60 years of age (P < .001) and Breslow thickness >0.8 mm (P = .03) were at increased risk for positive sentinel lymph node (SLN). Moreover, on multivariate analysis, the presence of dermal mitoses increased the odds of SLN positivity by 95% (odds ratio [OR] 1.95 [95% confidence interval {CI} 1.53-2.5], P < .001), ulceration by 63% (OR 1.63 [95% CI 1.21-2.18], P < .001), and Clark level IV to V by 48% (OR 1.48 [95% CI 1.19-1.85]). Patients without ulceration but with dermal mitoses had 92% (OR 1.92 [95% CI 1.5-2.48], P < .001) increased SLN positivity.

LIMITATIONS

Limited survival data are available.

CONCLUSIONS

Younger age, a Breslow thickness >0.8 mm, the presence of dermal mitoses, ulceration, and Clark level IV to V are positive predictors of positive SLN. While the new American Joint Committee on Cancer system has removed dermal mitotic rate from staging, continued evaluation of dermal mitotic rate could be valuable for guiding surgical decision making about SLNB.

Current management of regional lymph nodes in patients with melanoma

The publication of recent randomized trials has prompted a significant shift in both our understanding and the management of patients with melanoma. Here, the current management of the regional lymph nodes in patients with melanoma is discussed. This review focuses on selection for sentinel lymph node biopsy, management of the positive sentinel node, management of the clinically positive node, and the controversy over the therapeutic value of early nodal intervention.

Vertical Growth Phase as a Prognostic Factor for Sentinel Lymph Node Positivity in Thin Melanomas: A Systematic Review and Meta-Analysis

BACKGROUND

The 2010 American Joint Committee on Cancer guidelines recommended consideration of sentinel lymph node biopsy for thin melanoma (Breslow thickness <1.0 mm) with aggressive pathologic features such as ulceration and/or high mitotic rate. The therapeutic benefit of biopsy-based treatment remains controversial. The authors conducted a meta-analysis to estimate the risk and outcomes of sentinel lymph node positivity in thin melanoma, and examined established and potential novel predictors of positivity.

METHODS

Three databases were searched by two independent reviewers for sentinel lymph node positivity in patients with thin melanoma. Study heterogeneity, publication bias, and quality were assessed. Data collected included age, sex, Breslow thickness, mitotic rate, ulceration, regression, Clark level, tumor-infiltrating lymphocytes, and vertical growth phase. Positivity was estimated using a random effects model. Association of positivity and clinicopathologic features was investigated using meta-regression.

RESULTS

Ninety-three studies were identified representing 35,276 patients with thin melanoma who underwent sentinel lymph node biopsy. Of these patients, 952 had a positive sentinel lymph node biopsy, for an event rate of 5.1 percent (95 percent CI, 4.1 to 6.3 percent). Significant associations were identified between positivity and Breslow thickness greater than 0.75 mm but less than 1.0 mm, mitotic rate, ulceration, and Clark level greater than IV. Seven studies reported on vertical growth phase, which was strongly associated with positivity (OR, 4.3; 95 percent CI, 2.5 to 7.7).

CONCLUSIONS

To date, this is the largest meta-analysis to examine predictors of sentinel lymph node biopsy positivity in patients with thin melanoma. Vertical growth phase had a strong association with biopsy positivity, providing support for its inclusion in standardized pathologic reporting.

Guidelines of care for the management of primary cutaneous melanoma

The incidence of primary cutaneous melanoma continues to increase each year. Melanoma accounts for the majority of skin cancer-related deaths, but treatment is usually curative following early detection of disease. In this American Academy of Dermatology clinical practice guideline, updated treatment recommendations are provided for patients with primary cutaneous melanoma (American Joint Committee on Cancer stages 0-IIC and pathologic stage III by virtue of a positive sentinel lymph node biopsy). Biopsy techniques for a lesion that is clinically suggestive of melanoma are reviewed, as are recommendations for the histopathologic interpretation of cutaneous melanoma. The use of laboratory, molecular, and imaging tests is examined in the initial work-up of patients with newly diagnosed melanoma and for follow-up of asymptomatic patients. With regard to treatment of primary cutaneous melanoma, recommendations for surgical margins and the concepts of staged excision (including Mohs micrographic surgery) and nonsurgical treatments for melanoma in situ, lentigo maligna type (including topical imiquimod and radiation therapy), are updated. The role of sentinel lymph node biopsy as a staging technique for cutaneous melanoma is described, with recommendations for its use in clinical practice. Finally, current data regarding pregnancy and melanoma, genetic testing for familial melanoma, and management of dermatologic toxicities related to novel targeted agents and immunotherapies for patients with advanced disease are summarized.

Association Between Patient Age and Lymph Node Positivity in Thin Melanoma

Importance

More than half of all new melanoma diagnoses present as clinically localized T1 melanoma, yet sentinel lymph node biopsy (SLNB) is controversial in this population given the overall low yield. Guidelines for SLNB have focused on pathologic factors, but patient factors, such as age, are not routinely considered.

Objectives

To identify indicators of lymph node (LN) metastasis in thin melanoma in a large, generalizable data set and to evaluate the association between patient age and LN positivity.

Design, Setting, and Participants

A retrospective cohort study using the National Cancer Database, an oncology database representing patients from more than 1500 hospitals throughout the United States, was performed (2010-2013). Data analysis was conducted from October 1, 2016, to January 15, 2017. A total of 8772 patients with clinical stage I 0.50 to 1.0 mm thin melanoma undergoing wide excision and surgical evaluation of regional LNs were included for study.

Main Outcome and Measures

The primary outcome of interest was presence of melanoma in a biopsied regional LN. Clinicopathologic factors associated with LN positivity were characterized, using logistic regression. Age was categorized as younger than 40 years, 40 to 64 years, and 65 years or older for multivariable analysis. Classification tree analysis was performed to identify high-risk groups for LN positivity.

Results

Among the study cohort (n = 8772), 333 patients had nodal metastases, for an overall positivity rate of 3.8% (95% CI, 3.4%-4.2%). A total of 4087 (54.0%) patients were women. Median age was 56 years (interquartile range [IQR], 46-67) in patients with negative LNs and 52 years (IQR, 41-61) in those with positive LNs (P < .001). In multivariable analysis, younger age, female sex, thickness of 0.76 mm or larger, increasing Clark level, mitoses, ulceration, and lymphovascular invasion were independently associated with LN positivity. In decision tree analysis, patient age was identified as an important risk stratifier for LN metastases, after mitoses and thickness. Patients younger than 40 years with category T1b tumors 0.50 to 0.75 mm, who would generally not be recommended for SLNB, had an LN positivity rate of 5.6% (95% CI, 3.3%-8.6%); conversely, patients 65 years or older with T1b tumors 0.76 mm or larger, who would generally be recommended for SLNB, had an LN positivity rate of only 3.9% (95% CI, 2.7%-5.3%).

Conclusions and Relevance

Patient age is an important factor in estimating lymph node positivity in thin melanoma independent of traditional pathologic factors. Age therefore should be taken into consideration when selecting patients for nodal biopsy.

Identification of high-risk cutaneous melanoma tumors is improved when combining the online American Joint Committee on Cancer Individualized Melanoma Patient Outcome Prediction Tool with a 31-gene expression profile-based classification

BACKGROUND

A significant proportion of patients with American Joint Committee on Cancer (AJCC)-defined early-stage cutaneous melanoma have disease recurrence and die. A 31-gene expression profile (GEP) that accurately assesses metastatic risk associated with primary cutaneous melanomas has been described.

OBJECTIVE

We sought to compare accuracy of the GEP in combination with risk determined using the web-based AJCC Individualized Melanoma Patient Outcome Prediction Tool.

METHODS

GEP results from 205 stage I/II cutaneous melanomas with sufficient clinical data for prognostication using the AJCC tool were classified as low (class 1) or high (class 2) risk. Two 5-year overall survival cutoffs (AJCC 79% and 68%), reflecting survival for patients with stage IIA or IIB disease, respectively, were assigned for binary AJCC risk.

RESULTS

Cox univariate analysis revealed significant risk classification of distant metastasis-free and overall survival (hazard ratio range 3.2-9.4, P < .001) for both tools. In all, 43 (21%) cases had discordant GEP and AJCC classification (using 79% cutoff). Eleven of 13 (85%) deaths in that group were predicted as high risk by GEP but low risk by AJCC.

LIMITATIONS

Specimens reflect tertiary care center referrals; more effective therapies have been approved for clinical use after accrual.

CONCLUSIONS

The GEP provides valuable prognostic information and improves identification of high-risk melanomas when used together with the AJCC online prediction tool.

Thin Melanoma with Nodal Involvement: Analysis of Demographic, Pathologic, and Treatment Factors with Regard to Prognosis

BACKGROUND

Although only a small proportion of thin melanomas result in lymph node metastasis, the abundance of these lesions results in a relatively large absolute number of patients with a diagnosis of nodal metastases, determined by either sentinel lymph node (SLN) biopsy or clinical nodal recurrence (CNR).

METHODS

Independent cohorts with thin melanoma and either SLN metastasis or CNR were identified at two melanoma referral centers. At both centers, SLN metastasis patients were included. At center 1, the CNR cohort included patients with initial negative clinical nodal evaluation followed by CNR. At center 2, the CNR cohort was restricted to those presenting in the era before the use of SLN biopsy. Uni- and multivariable analyses of melanoma-specific survival (MSS) were performed.

RESULTS

At center 1, 427 CNR patients were compared with 91 SLN+ patients. The 5- and 10-year survival rates in the SLN group were respectively 88 and 84 % compared with 72 and 49 % in the CNR group (p < 0.0001). The multivariate analysis showed age older than 50 years (hazard ratio [HR] 1.5; 95 % confidence interval [CI] 1.2-1.9), present ulceration (HR 1.9; 95 % CI 1.2-2.9), unknown ulceration (HR 1.6; 95 % CI 1.3-2.1), truncal site (HR 1.6; 95 % CI 1.2-2.2), and CNR (HR 3.3; 95 % CI 1.8-6.0) to be associated significantly with decreased MSS (p < 0.01 for each). The center 2 cohort demonstrated remarkably similar findings, with a 5-year MSS of 88 % in the SLN (n = 29) group and 76 % in the CNR group (n = 39, p = 0.09).

CONCLUSION

Patients with nodal metastases from thin melanomas have a substantial risk of melanoma death. This risk is lower among patients whose disease is discovered by SLN biopsy rather than CNR.

Clinical utilities and biological characteristics of melanoma sentinel lymph nodes

An estimated 73870 people will be diagnosed with melanoma in the United States in 2015, resulting in 9940 deaths. The majority of patients with cutaneous melanomas are cured with wide local excision. However, current evidence supports the use of sentinel lymph node biopsy (SLNB) given the 15%-20% of patients who harbor regional node metastasis. More importantly, the presence or absence of nodal micrometastases has been found to be the most important prognostic factor in early-stage melanoma, particularly in intermediate thickness melanoma. This review examines the development of SLNB for melanoma as a means to determine a patient’s nodal status, the efficacy of SLNB in patients with melanoma, and the biology of melanoma metastatic to sentinel lymph nodes. Prospective randomized trials have guided the development of practice guidelines for use of SLNB for melanoma and have shown the prognostic value of SLNB. Given the rapidly advancing molecular and surgical technologies, the technical aspects of diagnosis, identification, and management of regional lymph nodes in melanoma continues to evolve and to improve. Additionally, there is ongoing research examining both the role of SLNB for specific clinical scenarios and the ways to identify patients who may benefit from completion lymphadenectomy for a positive SLN. Until further data provides sufficient evidence to alter national consensus-based guidelines, SLNB with completion lymphadenectomy remains the standard of care for clinically node-negative patients found to have a positive SLN.

Sentinel Lymph Node Biopsy in Thin Cutaneous Melanoma: A Systematic Review and Meta-Analysis

BACKGROUND

Most patients with melanoma have a thin (≤1.00 mm) lesion. There is uncertainty as to which patients with thin melanoma should undergo sentinel lymph node (SN) biopsy. We sought to quantify the proportion of SN metastases in patients with thin melanoma and to determine the pooled effect of high-risk features of the primary lesion on SN positivity.

METHODS

Published literature between 1980 and 2015 was searched and critically appraised. Primary outcome was the proportion of SN metastases in patients with thin cutaneous melanoma. Secondary outcomes included the effect of high-risk pathological features of the primary lesion on the proportion of SN metastases. Summary measures were estimated by Mantel-Haenszel method using random effects meta-analyses.

RESULTS

Sixty studies (10,928 patients) met the criteria for inclusion. Pooled SN positivity was 4.5 % [95 % confidence interval (CI) 3.8-5.2 %]. Predictors of a positive SN were: thickness ≥0.75 mm [adjusted odds ratio (AOR) 1.90 (95 % CI 1.08-3.34); with a likelihood of SN metastases of 8.8 % (95 % CI 6.4-11.2 %)]; Clark level IV/V [AOR 2.24 (95 % CI 1.23-4.08); with a likelihood of 7.3 % (95 % CI 6.2-8.4 %)]; ≥1 mitoses/mm² [AOR 6.64 (95 % CI 2.77-15.88); pooled likelihood 8.8 % (95 % CI 6.2-11.4 %)]; and the presence of microsatellites [unadjusted OR 6.94 (95 % CI 2.13-22.60); likelihood 26.6 % (95 % CI 4.3-48.9 %)].

CONCLUSIONS

The pooled proportion of SN metastases in thin melanoma is 4.5 %. Thickness ≥0.75 mm, Clark level IV/V, mitoses, and microsatellites significantly increased the odds of SN positivity and should prompt strong consideration of SN biopsy.

Update on Thin Melanoma: Outcome of an International Workshop

The following communication summarizes the proceedings of a 1-day Workshop of the International Melanoma Pathology Study Group, which was devoted to thin melanoma. The definitions and histologic criteria for thin melanoma were reviewed. The principal differential diagnostic problems mentioned included the distinction of thin melanoma from nevi, especially from nevi of special site, irritated nevi, inflamed and regressing nevi, and dysplastic nevi. Histologic criteria for this analysis were discussed and the importance of clinico-pathologic correlation, especially in acral sites, was emphasized. Criteria for the minimal definition of invasion were also discussed. In addition, a new technique of m-RNA expression profiling with 14 genes was presented and facilitated the distinction of thin melanomas from nevus in histologically obvious cases. However, for particular nevi, it was not obvious why the results indicated a malignant lesion. Despite many molecular and other ancillary investigations, Breslow thickness remains the most important prognostic factor in thin melanoma. The prognostic significance of radial (horizontal) and vertical growth phases, Clark level, regression, and mitotic rate were also discussed. Because of the increasing frequency of thin melanomas, there is a great need to develop more refined predictors of thin melanomas with worse clinical outcome.

Current staging and prognostic factors in melanoma

The current American Joint Commission for Cancer staging system for melanoma includes thickness, ulceration, and mitotic index as primary tumor factors for patients with stage I and II disease. Number and size of nodal metastases, presence of satellitosis and in-transit disease, and tumor ulceration status categorize patients with stage III disease. Presence and location of distant metastatic disease and increased lactate dehydrogenase level stratify prognosis in patients with stage IV disease. Factors predictive of sentinel lymph node positivity are also studied, particularly in patients with T1 melanomas, but are not always congruent with those predictive of survival.

Evaluation of Melanoma Features and Their Relationship with Nodal Disease: The Importance of the Pathological Report

Background

The pathological features of melanoma biopsies can provide significant prognostic information that can help the surgeon evaluate the risk of nodal disease. The aim of this study was to attempt to determine the relationship between pathological features of primary melanoma and nodal disease, by sentinel node biopsy (SNB) and complete node dissection (CND).

Methods

A retrospective analysis was completed of patients who underwent SNB at AC Camargo Cancer Center, Sao Paulo, Brazil, between 2000 and 2010.

Results

A total of 697 patients were evaluated. By univariate analysis, it was found that histology, Clark level, Breslow depth, mitotic index, ulceration, regression, lymphatic and perineural invasion and satellitosis were significantly associated with SNB positivity. In the multivariate analysis, it was found that Breslow depth, mitotic index, ulceration, regression, lymphatic invasion and satellitosis were significant factors. In patients with a positive SNB, the primary tumor site, Clark level and Breslow depth greater than 2 mm were significantly related to non-sentinel node (NSN) positivity by univariate analysis. By multivariate analysis, Breslow depth greater than 2 mm was the only primary tumor feature that was significantly related (p = 0.038).

Conclusions

The indication of SNB should not be based solely on Breslow depth and ulceration or mitotic index. A complete evaluation of the pathological report should improve the identification of high-risk patients.

Identification of Patients with Intermediate Thickness Melanoma at Low Risk for Sentinel Lymph Node Positivity

INTRODUCTION

Sentinel lymph node (SLN) biopsy is recommended for all patients with intermediate-thickness melanomas. We sought to identify such patients at low risk of SLN positivity.

METHODS

All patients with intermediate-thickness melanomas (1.01-4 mm) undergoing SLN biopsy at a single institution from 1995-2011 were included in this retrospective cohort study. Univariate and multivariate logistic regression determined factors associated with a low risk of SLN positivity. Classification and regression tree (CART) analysis was used to stratify groups based on risk of positivity.

RESULTS

Of the 952 study patients, 157 (16.5 %) had a positive SLN. In the multivariate analysis, thickness <1.5 mm (odds ratio [OR] 0.29), age ≥60 (OR 0.69), present tumor-infiltrating lymphocytes (OR 0.60), absent lymphovascular invasion (OR 0.46), and absent satellitosis (OR 0.44) were significantly associated with a low risk of SLN positivity. CART analysis identified thickness of 1.5 mm as the primary cut point for risk of SLN metastasis. Patients with a thickness of <1.5 mm represented 36 % of the total cohort and had a SLN positivity rate of 6.6 % (95 % confidence interval 3.8-9.4 %). In patients with melanomas <1.5 mm in thickness, the presence of additional low risk factors identified 257 patients (75 % of patients with <1.5 mm melanomas) in which the rate of SLN positivity was <5 %.

CONCLUSIONS

Despite a SLN positivity rate of 16.5 % overall, substantial heterogeneity of risk exists among patients with intermediate-thickness melanoma. Most patients with melanoma between 1.01 and 1.5 mm have a risk of SLN positivity similar to that in patients with thin melanomas.

EANM practice guidelines for lymphoscintigraphy and sentinel lymph node biopsy in melanoma

PURPOSE

Sentinel lymph node biopsy is an essential staging tool in patients with clinically localized melanoma. The harvesting of a sentinel lymph node entails a sequence of procedures with participation of specialists in nuclear medicine, radiology, surgery and pathology. The aim of this document is to provide guidelines for nuclear medicine physicians performing lymphoscintigraphy for sentinel lymph node detection in patients with melanoma.

METHODS

These practice guidelines were written and have been approved by the European Association of Nuclear Medicine (EANM) to promote high-quality lymphoscintigraphy. The final result has been discussed by distinguished experts from the EANM Oncology Committee, national nuclear medicine societies, the European Society of Surgical Oncology (ESSO) and the European Association for Research and Treatment of Cancer (EORTC) melanoma group. The document has been endorsed by the Society of Nuclear Medicine and Molecular Imaging (SNMMI).

CONCLUSION

The present practice guidelines will help nuclear medicine practitioners play their essential role in providing high-quality lymphatic mapping for the care of melanoma patients.

Gene expression profiling for molecular staging of cutaneous melanoma in patients undergoing sentinel lymph node biopsy

BACKGROUND

A gene expression profile (GEP) test able to accurately identify risk of metastasis for patients with cutaneous melanoma has been clinically validated.

OBJECTIVE

We aimed for assessment of the prognostic accuracy of GEP and sentinel lymph node biopsy (SLNB) tests, independently and in combination, in a multicenter cohort of 217 patients.

METHODS

Reverse transcription polymerase chain reaction (RT-PCR) was performed to assess the expression of 31 genes from primary melanoma tumors, and SLNB outcome was determined from clinical data. Prognostic accuracy of each test was determined using Kaplan-Meier and Cox regression analysis of disease-free, distant metastasis-free, and overall survivals.

RESULTS

GEP outcome was a more significant and better predictor of each end point in univariate and multivariate regression analysis, compared with SLNB (P < .0001 for all). In combination with SLNB, GEP improved prognostication. For patients with a GEP high-risk outcome and a negative SLNB result, Kaplan-Meier 5-year disease-free, distant metastasis-free, and overall survivals were 35%, 49%, and 54%, respectively.

LIMITATIONS

Within the SLNB-negative cohort of patients, overall risk of metastatic events was higher (∼30%) than commonly found in the general population of patients with melanoma.

CONCLUSIONS

In this study cohort, GEP was an objective tool that accurately predicted metastatic risk in SLNB-eligible patients.