Regional Nodal Metastatic Disease Is the Strongest Predictor of Survival in Patients with Thin Vertical Growth Phase Melanomas: A Case for SLN Staging Biopsy in These Patients

Molecular Biomarkers for Melanoma Screening, Diagnosis and Prognosis: Current State and Future Prospects

Despite significant progress in the development of treatment options, melanoma remains a leading cause of death due to skin cancer. Advances in our understanding of the genetic, transcriptomic, and morphologic spectrum of benign and malignant melanocytic neoplasia have enabled the field to propose biomarkers with potential diagnostic, prognostic, and predictive value. While these proposed biomarkers have the potential to improve clinical decision making at multiple critical intervention points, most remain unvalidated. Clinical validation of even the most commonly assessed biomarkers will require substantial resources, including limited clinical specimens. It is therefore important to consider the properties that constitute a relevant and clinically-useful biomarker-based test prior to engaging in large validation studies. In this review article we adapt an established framework for determining minimally-useful biomarker test characteristics, and apply this framework to a discussion of currently used and proposed biomarkers designed to aid melanoma detection, staging, prognosis, and choice of treatment.

Nonsurgical Management of Lymph Node Basins in Melanoma

In this article we provide a critical review of the evidence available for surgical management of the nodal basin in melanoma, with an aim to ensure an understanding of risks and benefits for all lymph node surgery offered to patients, and alternatives to surgical management where appropriate.

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.

The prognostic significance of tumor-infiltrating lymphocytes for primary melanoma varies by sex

BACKGROUND

The immune response to melanoma is manifested locally by tumor-infiltrating lymphocytes (TILs). Men and women are known to have varying patterns of immunity, yet sex-specific prognostic implications of TILs have not been explored.

METHODS

Patients who had clinically localized primary melanoma with a Breslow thickness of 0.76 mm or more and underwent sentinel lymph node (SLN) biopsy at our institution were identified. The association between TILs (absent, nonbrisk, and brisk) and SLN positivity was evaluated by using logistic regression. Overall survival (OS) was evaluated by TIL status and sex.

RESULTS

Among 1367 patients identified, 794 were men. TILs were brisk in 143 lesions, nonbrisk in 903, and absent in 321, which did not vary by sex (P = .71). SLN positivity was associated with TILs among men (brisk, 3.8%; nonbrisk, 16.9%; and absent, 26.6% [P < .001]). In contrast, there was no association between SLN positivity and TILs among women (P = .49). Interaction between brisk TILs and sex on SLN positivity was significant (P = .029). Among men, presence of brisk TILs was associated with prolonged OS (P = .038) but not after adjustment for SLN status (P = .42). There was no association between TIL status and OS among women.

LIMITATIONS

Findings from this single-institution study have yet to be validated by other research groups.

CONCLUSIONS

The implications of TILs in predicting SLN positivity appear to be more relevant for men than for women.

Stratifying SLN incidence in intermediate thickness melanoma patients

BACKGROUND

Guidelines for melanoma recommend sentinel lymph node biopsy (SLNB) in patients with melanomas ≥1 mm thickness. Recent single institution studies have found tumors <1.5 mm a low-risk group for positive SLNB.

METHODS

A retrospective review of the Sentinel Lymph Node Working Group multicenter database identified patients with intermediate thickness melanoma (1.01-4.00 mm) who had SLNB, and assessed predictors for positive SLNB.

RESULTS

3460 patients were analyzed, 584 (17%) had a positive SLNB. Univariate factors associated with a positive SLNB included age <60 (p < .001), tumor on the trunk/lower extremity (p < .001), Breslow depth ≥2 mm (p < .001), ulceration (p < .001), mitotic rate ≥1/mm² (p = .01), and microsatellitosis (p < .001). Multivariate analysis revealed age, location, and Breslow depth as significant predictors. Patients ≥75 with lesions 1.01-1.49 mm on the head/neck/upper extremity and 1.5-1.99 mm without high-risk features had <5% risk of SLN positivity.

CONCLUSIONS

Intermediate thickness melanoma has significant heterogeneity of SLNB positivity. Low-risk subgroups can be found among older patients in the absence of high-risk features.

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.

Principles of Melanoma Staging

Although now commonplace in contemporary cancer care, the systematic approach to classification of disease-specific cancers into a formalized staging system is a relatively modern concept. Overall, the goals of cancer staging are to characterize the status of cancer at a specific moment in time, risk stratify, facilitate prognostication, and inform clinical decision making. The revisions to the American Joint Committee on Cancer (AJCC) melanoma staging system over time reflect changes in our understanding of the biology of the disease. Since the 1st edition, where tumor thickness was defined anatomically by its relationship to the reticular or papillary dermis (Clark level) as well as tumor thickness (Breslow thickness), there have been significant strides in our use of clinicopathological variables to stratify low- versus high-risk patients. Management of the regional nodal basin has also changed dramatically over time, impacted by techniques such as lymphatic mapping and sentinel lymph node biopsy (SLNB) and changes in pathological evaluation of the regional lymph nodes. Additionally, stratification of distant metastases has evolved as survival outcomes have been shown to vary based upon anatomic site of metastases and serum lactate dehydrogenase levels. The variables in use in the current (7th edition) AJCC staging system are surrogate markers of biology with validated impact of survival outcomes. Going forward, it is likely that these and additional clinicopathological factors will be integrated with molecular and other correlates of melanoma tumor biology to further refine and personalize melanoma staging.

Prognostic factors in melanoma patients with tumor-negative sentinel lymph nodes

BACKGROUND

Sentinel lymph node (SLN) biopsy for melanoma results in accurate nodal staging, which guides treatment decisions. Patients with a negative SLN biopsy in general have a favorable prognosis, but certain subsets are at increased risk for recurrence and death. This study aimed to identify risk factors predictive of prognosis in patients with a tumor-negative SLN biopsy for cutaneous melanoma.

METHODS

In this post-hoc analysis of data from a multicenter prospective randomized trial, clinicopathologic data of patients with cutaneous melanoma ≥1.0 mm Breslow thickness and tumor-negative SLN were analyzed. Disease-free survival, overall survival (OS), and local and in-transit recurrence-free survival were compared by Kaplan-Meier analysis. Risk factors for worse survival were identified with Cox proportional hazard models.

RESULTS

This analysis included 1,998 patients with tumor-negative SLN with a median follow-up of 70 months. Ulceration, Breslow thickness, nonextremity tumor location, and age ≥45 years were independent risk factors for worse disease-free survival and OS. Breslow thickness and ulceration were the only factors on multivariate analysis that predicted local and in-transit recurrence-free survival. Estimated 5-year OS rates ranged from 55.5 to 95.4% on the basis of the defined risk factors.

CONCLUSION

There is a wide range of prognosis among patients with tumor-negative SLN. Breslow thickness, ulceration, age, and anatomic location of the primary melanoma are important independent factors predicting survival and recurrence among such patients. These factors can be used to stratify prognosis among patients with tumor-negative SLN to formulate rational long-term follow-up strategies as well as identify high-risk, SLN-negative patients for clinical trials of adjuvant therapy.

Surgical Management of Melanoma

The surgical management of melanoma has undergone considerable changes over the past several decades, as new strategies and treatments have become available. Surgeons play a pivotal role in all aspects of melanoma care: diagnostic, curative, and palliative. There is a high potential for cure in patients with early-stage melanoma and the selection of an appropriate operation is very important for this reason. Staging the nodal basin has become widespread since the adoption of sentinel lymph node biopsy (SLNB) for the management of melanoma. This operation provides the best prognostic information that is currently available for patients with melanoma. The surgeon plays a central role in the palliation of symptoms resulting from nodal disease and metastases, as melanoma has a propensity to spread to almost any site in the body.

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.

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.

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

BACKGROUND

The role for sentinel lymph node biopsy (SLNB) in patients with thin melanoma (≤1 mm) remains controversial. We examined a large cohort of patients with thin melanoma to better define predictors of SLN positivity.

METHODS

From 1995 to 2011, 781 patients with thin primary melanoma and evaluable clinicopathologic data underwent SLNB at our institution. Predictors of SLN positivity were determined using univariate and multivariate regression analyses, and patients were risk-stratified using a classification and regression tree (CART) analysis.

RESULTS

In the study cohort (n = 781), 29 patients (3.7%) had nodal metastases. In the univariate analysis, mitotic rate [odds ratio (OR) = 8.11, p = 0.005], Clark level (OR 4.04, p = 0.003), and thickness (OR 3.33, p = 0.011) were significantly associated with SLN positivity. In the multivariate analysis, MR (OR 7.01) and level IV-V (OR 3.45) remained significant predictors of SLN positivity. CART analysis initially stratified lesions by mitotic rate; nonmitogenic lesions (n = 273) had a 0.7% SLN positivity rate versus 5.6% in mitogenic lesions (n = 425). Mitogenic lesions were further stratified by Clark level; patients with level II-III had a 2.9% SLN positivity rate (n = 205) versus 8.2% with level IV-V (n = 220). With median follow-up of 6.3 years, five SLN-negative patients developed nodal recurrence and four SLN-positive patients died of disease.

CONCLUSIONS

SLN positivity is low in patients with thin melanoma (3.7%) and exceedingly so in nonmitogenic lesions (0.7%). Appreciable rates of SLN positivity can be identified in patients with mitogenic lesions, particularly with concurrent level IV-V regardless of thickness. These factors may guide appropriate selection of patients with thin melanoma for SLNB.

Conditional survival after surgical treatment of melanoma: an analysis of the Surveillance, Epidemiology, and End Results database

BACKGROUND

Survival curves following surgical treatment of cutaneous melanoma are heavily influenced by early deaths. Therefore, survival estimates may be misleading for long-term cancer survivors. We examined whether conditional survival (CS) is more accurate in predicting long-term melanoma survival.

METHODS

We used the Surveillance, Epidemiology, and End Results database (1992-2005) to identify patients who underwent surgical treatment for melanoma. We included patients with T2-T4 disease and with known nodal status. Patients were stratified into low-risk (T2-3N0M0) and high-risk (T4N0M0 or T2-4N1-3M0) categories. We defined CS as time-specific estimates conditioned on living to a certain point in follow-up, and calculated 10-year cancer-specific survival curves conditioned on annual survival. We adjusted for potential confounders using a Cox proportional hazards regression model (alpha = 0.05).

RESULTS

A total of 8647 patients met inclusion criteria (low-risk, 5987 [69.2%]; high-risk, 2660 [30.8%]). At diagnosis, low-risk patients had a significantly better 10-year survival rate (low-risk, 79.6%; high-risk, 41.2%; P < 0.001). On CS analysis, survival differences remained until 8 years after treatment, after which 10-year cancer-specific survival rates were no longer significantly different (P = 0.51) for low-risk (95.4%) and high-risk (91.7%) groups. Multivariate analysis demonstrated that age, gender, location, and ulceration (initial predictors of survival) were no longer predictive after 8 years of survival.

CONCLUSIONS

For patients who survive 8 years after surgical treatment of melanoma, CS data become discordant with traditionally used estimates. Our findings have important implications for patient counseling, as high-risk melanoma survivors may require no more intensive surveillance than low-risk survivors 8 years after treatment.

The classification of cutaneous melanoma

Forty years ago, a clinical and histological classification scheme and prognostic factors were described for cutaneous melanoma. This scheme included the subtypes superficial spreading, nodular and lentigo maligna, and prognostic factors including tumor thickness, ulceration, and mitotic activity. There have been some tweaks to the classification scheme, but these basic findings form the foundation for melanoma diagnosis and staging today. Currently, no molecular marker or target has proved reliably useful in the staging or treatment of melanoma. Measurement with a simple ruler serves as the basis for the staging of primary cutaneous melanoma, while the recognition of primary tumor mitotic activity and ulceration also remain significant factors. Recently, mutational analysis has revealed a correlation of activating mutations with the morphological descriptors from decades ago. Future classification schemes may have more power in predicting response to therapy by integrating specific genomic and intra-tumoral expression profiles with histologic findings.

Multidisciplinary treatment of primary melanoma

This article covers the multidisciplinary treatment of primary melanoma. Excision margins and the need for sentinel lymphadenectomy are mainly dictated by the Breslow thickness although exceptions to this dictum do exist. Interferon is the only FDA approved adjuvant therapy for high risk melanoma although its overall survival benefit is minimal. Trials examining different doses or duration of interferon therapy have not demonstrated any promising survival data so far. There have been several randomized vaccine trials for melanoma but none have shown an overall survival benefit. Research into T-cell regulation continues and will hopefully bring promise for the future of melanoma treatment.

Importance of sentinel lymph node biopsy in patients with thin melanoma

HYPOTHESIS

The status of the sentinel node (SN) confers important prognostic information for patients with thin melanoma.

DESIGN, SETTING, AND PATIENTS

We queried our melanoma database to identify patients undergoing sentinel lymph node biopsy for thin (< or =1.00-mm) cutaneous melanoma at a tertiary care cancer institute. Slides of tumor-positive SNs were reviewed by a melanoma pathologist to confirm nodal status and intranodal tumor burden, defined as isolated tumor cells, micrometastasis, or macrometastasis (< or =0.20, 0.21-2.00, or >2.00 mm, respectively). Nodal status was correlated with patient age and primary tumor depth (< or = 0.25, 0.26-0.50, 0.51-0.75, or 0.76-1.00 mm). Survival was determined by log-rank test.

MAIN OUTCOME MEASURES

Disease-free and melanoma-specific survival.

RESULTS

Of 1592 patients who underwent sentinel lymph node biopsy from 1991 to 2004, 631 (40%) had thin melanomas; 31 of the 631 patients (5%) had a tumor-positive SN. At a median follow-up of 57 months for the 631 patients, the mean (SD) 10-year rate of disease-free survival was 96% (1%) vs 54% (10%) for patients with tumor-negative vs tumor-positive SNs, respectively (P < .001); the mean (SD) 10-year rate of melanoma-specific survival was 98% (1%) vs 83% (8%), respectively (P < .001). Tumor-positive SNs were more common in patients aged 50 years and younger (P = .04). The SN status maintained importance on multivariate analysis for both disease-free survival (P < .001) and melanoma-specific survival (P < .001).

CONCLUSIONS

The status of the SN is significantly linked to survival in patients with thin melanoma. Therefore, sentinel lymph node biopsy should be considered to obtain complete prognostic information.