Mitotic Rate and Younger Age Are Predictors of Sentinel Lymph Node Positivity: Lessons Learned From the Generation of a Probabilistic Model

Tumor-infiltrating lymphocyte response in cutaneous melanoma in the elderly predicts clinical outcomes

Tumor-infiltrating lymphocytes (TILs) and regression are manifestations of the host immune response to tumor, but their influence on outcome remains undefined. There is a paucity of data on the elderly who represent a growing proportion of melanoma patients. The aim of this study was to evaluate the influence of TILs and regression as an indirect measure of immunity on outcome in elderly patients with melanoma. From a prospective database, we identified 250 consecutive cutaneous melanoma patients aged at least 65 years at the time of diagnosis. Data were verified by record review. Within the primary melanoma, a brisk TIL response was present in 66 (31%), nonbrisk TILs in 36 (17%), and absent in 111 (52%). The presence of a brisk infiltrate conferred a three-fold increased risk of sentinel lymph node (SLN) metastasis (P=0.02). Despite this, nonbrisk or absent TILs were associated with a five-fold increased risk of recurrence (P=0.0001). In multivariate analysis, nonbrisk or absent TILs were independently associated with recurrence (P<0.0001), diminished 5-year disease-free survival (76 vs. 91%, P=0.0006), and 5-year melanoma-specific survival (82 vs. 95%, P=0.0008). Regression was not an independent predictor of SLN metastasis, disease-free survival, or melanoma-specific survival. Our study demonstrates that an active antitumor immune response exists in elderly melanoma patients that, paradoxically, predicts both SLN metastasis and improved melanoma-specific outcomes. Further investigation to characterize this lymphocytic infiltrate and to confirm its clinical significance as a predictor of nodal status, patient outcome, and response to immunotherapy in elderly melanoma patients appears warranted.

Integrating molecular biomarkers into current clinical management in melanoma

Personalized melanoma medicine has progressed from histopathologic features to serum markers to molecular profiles. Since the identification of activating BRAF mutations and subsequent development of drugs targeting the mutant BRAF protein, oncologists now need to incorporate prognostic and predictive biomarkers into treatment decisions for their melanoma patients. Examples include subgrouping patients by genotype profiles for targeted therapy and the development of serologic, immunohistochemical, and genotype profiles for the selection of patients for immunotherapies. In this chapter, we provide an overview of the current status of BRAF mutation testing, as well as promising serologic and molecular profiles that will impact patient care. As further research helps clarify the roles of these factors, the clinical outcomes of melanoma patients promise to be greatly improved.

Clinicopathologic predictors of sentinel lymph node metastasis in thin melanoma

PURPOSE

Indications for sentinel lymph node biopsy (SLNB) for thin melanoma are continually evolving. We present a large multi-institutional study to determine factors predictive of sentinel lymph node (SLN) metastasis in thin melanoma.

PATIENTS AND METHODS

Retrospective review of the Sentinel Lymph Node Working Group database from 1994 to 2012 identified 1,250 patients who had an SLNB and thin melanomas (≤ 1 mm). Clinicopathologic characteristics were correlated with SLN status and outcome.

RESULTS

SLN metastases were detected in 65 (5.2%) of 1,250 patients. On univariable analysis, rates of Breslow thickness ≥ 0.75 mm, Clark level ≥ IV, ulceration, and absence of regression differed significantly between positive and negative SLN groups (all P < .05). These four variables and mitotic rate were used in multivariable analysis, which demonstrated that Breslow thickness ≥ 0.75 mm (P = .03), Clark level ≥ IV (P = .05), and ulceration (P = .01) significantly predicted SLN metastasis with 6.3%, 7.0%, and 11.6% of the patients with these respective characteristics having SLN disease. Melanomas < 0.75 mm had positive SLN rates of < 5% regardless of Clark level and ulceration status. Median follow-up was 2.6 years. Melanoma-specific survival was significantly worse for patients with positive versus negative SLNs (P = .001).

CONCLUSION

Breslow thickness ≥ 0.75 mm, Clark level ≥ IV, and ulceration significantly predict SLN disease in thin melanoma. Most SLN metastases (86.2%) occur in melanomas ≥ 0.75 mm, with 6.3% of these patients having SLN disease, whereas in melanomas < 0.75 mm, SLN metastasis rates are < 5%. By using a 5% metastasis risk threshold, SLNB is indicated for melanomas ≥ 0.75 mm, but further study is needed to define indications for SLNB in melanomas < 0.75 mm.

Is head and neck melanoma different from trunk and extremity melanomas with respect to sentinel lymph node status and clinical outcome?

BACKGROUND

Previous studies showed conflicting and inconsistent results regarding the effect of anatomic location of the melanoma on sentinel lymph node (SLN) positivity and/or survival. This study was conducted to evaluate and compare the effect of the anatomic locations of primary melanoma on long-term clinical outcomes.

METHODS

All consecutive cutaneous melanoma patients (n=2,079) who underwent selective SLN dissection (SLND) from 1993 to 2009 in a single academic tertiary-care medical center were included. SLN positive rate, disease-free survival (DFS), and overall survival (OS) were determined. Kaplan-Meier survival, univariate, and multivariate analyses were performed to determine predictive factors for SLN status, DFS, and OS.

RESULTS

Head and neck melanoma (HNM) had the lowest SLN-positive rate at 10.8% (16.8% for extremity and 19.3% for trunk; P=0.002) but had the worst 5-year DFS (P<0.0001) and 5-year OS (P<0.0001) compared with other sites. Tumor thickness (P<0.001), ulceration (P<0.001), HNM location (P=0.001), mitotic rate (P<0.001), and decreasing age (P<0.001) were independent predictive factors for SLN-positivity. HNM with T3 or T4 thickness had significantly lower SLN positive rate compared with other locations (P≤0.05). Also, on multivariate analysis, HNM location versus other anatomic sites was independently predictive of decreased DFS and OS (P<0.001). By Kaplan-Meier analysis, HNM was associated significantly with the worst DFS and OS.

CONCLUSIONS

Primary melanoma anatomic location is an independent predictor of SLN status and survival. Although HNM has a decreased SLN-positivity rate, it shows a significantly increased risk of recurrence and death as compared with other sites.

Prognostic significance of drainage to pelvic nodes at sentinel lymph node mapping in patients with extremity melanoma

Patients undergoing sentinel lymph node (SLN) mapping for lower extremity melanoma may have drainage to pelvic nodes (DPN) in addition to superficial inguinal nodes. These nodes are not sampled routinely at SLN biopsy. Factors predicting DPN and its prognostic significance were assessed in a large cohort of patients undergoing an SLN biopsy. Three hundred and twenty five patients with single primary melanomas of the lower extremity or buttocks who underwent SLN mapping were identified from our prospective melanoma database (December 1995-October 2008). Associations of clinical and pathologic factors with DPN and time to melanoma recurrence (TTR) were analyzed by logistic and Cox regression, respectively. DPN was common, occurring in 23% of cases. Increased Breslow's thickness (P=0.007) and age (P=0.01) were associated with DPN by multivariate analysis. Patients with DPN were not more likely to have a positive SLN; however, SLN- patients with DPN showed a shorter TTR (P=0.02) in a multivariable model including thickness and ulceration. With age included in the model, DPN remained marginally associated with TTR in this group (P=0.08). The pelvic recurrence rates observed were similar in recurrent patients with DPN compared with those without DPN (39% in both groups). In conclusion, DPN occurs in almost one-quarter of patients with lower extremity melanoma and is marginally associated with a shorter TTR in SLN- patients.

Outcome of sentinel lymph node biopsy and prognostic implications of regression in thin malignant melanoma

Thin melanomas with partial or complete regression may provide clues about antitumor immunity, but their management remains controversial. We have characterized the management and clinical outcomes of regressed thin (<1 mm) T1a melanomas and hypothesized that regression increases the risk of regional metastases when compared with nonregressed thin melanomas. A prospectively collected clinical database was reviewed, and T1a melanomas with regression were identified. Histology, surgical approach, outcome, and survival were evaluated. The primary outcome measures were sentinel node positivity, subsequent lymph node metastasis, and survival. A total of 75 patients with T1a or in-situ melanomas were grouped into three subsets. Group 1: 35 underwent a sentinel node biopsy (SNBx), none of which were positive. No patients developed nodal recurrence. The 5-year survival of this group was 93%, with a median follow-up of 52 months. Group 2: 31 were followed up without SNBx; two developed regional nodal disease (6.5%), neither of whom died of subsequent distant disease. The 5-year survival was 89%, with a median follow-up of 38 months. There was no significant difference in the survival between groups 1 and 2. Group 3: nine patients presented with metastatic disease concurrent with a regressed thin melanoma. These patients had a median survival of 2.3 years and a 4-year survival estimate of 22%. Regression should not be used as an indication for SNBx in T1a melanomas; we recommend that such patients be managed with wide local excision and a long-term clinical follow-up. The poor prognosis of thin regressed primary melanoma with simultaneous metastatic disease may indicate the existence of immune escape phenotypes supporting melanoma progression.

Sentinel lymph node biopsy for melanoma: American Society of Clinical Oncology and Society of Surgical Oncology joint clinical practice guideline

PURPOSE

The American Society of Clinical Oncology (ASCO) and Society of Surgical Oncology (SSO) sought to provide an evidence-based guideline on the use of lymphatic mapping and sentinel lymph node (SLN) biopsy in staging patients with newly diagnosed melanoma.

METHODS

A comprehensive systematic review of the literature published from January 1990 through August 2011 was completed using MEDLINE and EMBASE. Abstracts from ASCO and SSO annual meetings were included in the evidence review. An Expert Panel was convened to review the evidence and develop guideline recommendations.

RESULTS

Seventy-three studies met full eligibility criteria. The evidence review demonstrated that SLN biopsy is an acceptable method for lymph node staging of most patients with newly diagnosed melanoma.

RECOMMENDATIONS

SLN biopsy is recommended for patients with intermediate-thickness melanomas (Breslow thickness, 1 to 4 mm) of any anatomic site; use of SLN biopsy in this population provides accurate staging. Although there are few studies focusing on patients with thick melanomas (T4; Breslow thickness, > 4 mm), SLN biopsy may be recommended for staging purposes and to facilitate regional disease control. There is insufficient evidence to support routine SLN biopsy for patients with thin melanomas (T1; Breslow thickness, < 1 mm), although it may be considered in selected patients with high-risk features when staging benefits outweigh risks of the procedure. Completion lymph node dissection (CLND) is recommended for all patients with a positive SLN biopsy and achieves good regional disease control. Whether CLND after a positive SLN biopsy improves survival is the subject of the ongoing Multicenter Selective Lymphadenectomy Trial II.

Sentinel node biopsy is indicated for thin melanomas ≥0.76 mm

BACKGROUND

A consensus for which patients with thin melanomas (≤1 mm) should undergo sentinel lymph node biopsy (SLNB) is not established. We describe a large single institution experience with SLNB for thin melanomas to determine factors predictive of nodal metastases.

METHODS

Retrospective review from 2005 to 2010 identified 271 patients with thin melanomas who underwent SLNB, along with 13 additional patients not treated with SLNB who developed a nodal recurrence as first site of recurrence. Clinicopathologic characteristics were correlated with nodal status and outcome.

RESULTS

Median age was 55 years, and 53% of patients were male. Median Breslow thickness was 0.85 mm. Overall, a positive sentinel lymph node (SLN) was found in 22 (8.1%) of 271 cases; 8.4% of melanomas ≥0.76 mm were SLN positive with 5% of T1a melanomas ≥0.76 mm and 13% of T1b melanomas ≥0.76 mm having SLN metastases. Only two of 33 highly selected patients with melanomas <0.76 mm (both T1b) had a positive SLN. Logistic regression analysis demonstrated that mitotic rate ≥1/mm(2) significantly correlated with nodal disease (p < 0.05) and ulceration correlated with SLN metastases (p < 0.05). Median follow-up was 2.1 years. Overall survival did not differ between positive and negative SLN patients (p = 0.53) but was worse for patients presenting with a nodal recurrence (p < 0.01).

CONCLUSIONS

SLN metastases were seen in 8.4% of thin melanomas ≥0.76 mm, including 5% of T1a melanomas ≥0.76 mm. We believe these rates are sufficient to justify consideration of SLNB in these patients, while the indications for SLNB in melanomas <0.76 mm remain to be defined.

Aberrant hypermethylation in primary tumours and sentinel lymph node metastases in paediatric patients with cutaneous melanoma

BACKGROUND

Debate on how to manage paediatric patients with cutaneous melanoma continues, particularly in those with sentinel lymph node (SLN) metastases who are at higher risk of poor outcomes. Management is often based on adult algorithms, although differences in clinical outcomes between paediatric and adult patients suggest that melanoma in paediatric patients differs biologically. Yet, there are no molecular prognostic studies identifying these differences.

OBJECTIVES

We investigated the epigenetic (methylation) regulation of several tumour-related genes (TRGs) known to be significant in adult melanoma progression in histopathology(+) SLN metastases (n = 17) and primary tumours (n = 20) of paediatric patients with melanoma to determine their clinical relevance.

METHODS

Paediatric patients (n = 37; ≤ 21 years at diagnosis) with American Joint Committee on Cancer stage I-III cutaneous melanoma were analysed. Gene promoter methylation of the TRGs RASSF1A, RARβ2, WIF1 and APC was evaluated.

RESULTS

Hypermethylation of RASSF1A, RARβ2, WIF1 and APC was found in 29% (5/17), 25% (4/16), 25% (4/16) and 19% (3/16) of histopathology(+) SLNs, respectively. When matched to adult cutaneous melanomas by Breslow thickness and ulceration, hypermethylation of all four TRGs in SLN(+) paediatric patients with melanoma was equivalent to or less than in adults. With a median follow-up of 55 months, SLN(+) paediatric patients with melanoma with hypermethylation of > 1 TRG vs. ≤ 1 TRG had worse disease-free (P = 0·02) and overall survival (P = 0·02).

CONCLUSIONS

Differences in the methylation status of these TRGs in SLN(+) paediatric and adult patients with melanoma may account for why SLN(+) paediatric patients have different clinical outcomes. SLN biopsy should continue to be performed; within SLN(+) paediatric patients with melanoma, hypermethylation of TRGs can be used to identify a subpopulation at highest risk for poor outcomes who warrant vigilant clinical follow-up.

A brief history of melanoma: from mummies to mutations

In recent years, melanoma research has undergone a renaissance. What was once viewed, at least in the metastatic setting, as an intractable and untreatable disease is now revealing its molecular weaknesses. 2011 was a landmark year for melanoma therapy, with two new agents, the anti-CTLA4 antibody ipilimumab and the BRAF inhibitor vemurafenib, shown to confer a survival benefit in randomized phase III clinical trials. Overlooked in the recent flurry of interest that has accompanied the development of these drugs, melanoma is in fact an ancient disease that has long frustrated attempts at therapeutic interventions. In this article, we trace the history of melanoma: from the earliest known cases of melanoma in pre-Colombian South America, through the explorations of the Victorian anatomists right up to the molecular biology revolution of the 20th century that allowed for the identification of the key driving events required for melanomagenesis. We further outline how observations about melanoma heterogeneity, first made over 190 years ago, continue to drive our efforts to reduce melanoma to the level of a chronic, manageable disease and ultimately to cure it entirely.

Increasing Age Is Associated with Worse Prognostic Factors and Increased Distant Recurrences despite Fewer Sentinel Lymph Node Positives in Melanoma

Background. Advanced age is associated with a poorer prognosis in patients with melanoma. Despite this established finding, a decreased incidence of positive sentinel lymph nodes (SLNs) with advancing age has paradoxically been described. Methods. Using a single-institution database of melanoma patients between 1994 and 2009, the relationship between standard clinicopathologic variables and recurrence based on age was evaluated. Results. 1244 patients who underwent successful SLN biopsies were analyzed (mean followup 80.3 months). Increasing age was independently associated with worse survival on multivariable analysis (P = 0.02). SLN status was more likely to be negative if the patient was older (P = 0.01). Conclusions. Our data supports the paradox that increasing age is associated with a lower frequency of positive-SLN biopsies despite age itself being a poor prognostic factor. We propose that age-dependent variations in the primary tumor and the patient may predispose to a hematogenous route of spread for the older population, leading to worse survival.

Advances in sentinel lymph node mapping for patients with melanoma

Sentinel lymph node mapping allows accurate pathological staging for patients with cutaneous melanoma and clinically normal regional nodes. Early technical advances facilitated its widespread acceptance by surgeons. Morbidity as a result of the procedure is well established, but the potential benefit of providing powerful prognostic information outweighs these risks in most patients with intermediate-risk disease.

Malignant melanoma in the elderly: different regional disease and poorer prognosis

Purpose: Age is a poor prognostic factor in melanoma patients. Elderly melanoma patients have a different presentation and clinical course than younger patients. We evaluated the impact of age ≥70 years (yrs) on the diagnosis and natural history of melanoma.

Methods: Retrospective review of 610 patients with malignant melanoma entered into a prospective sentinel lymph node (SLN) database, treated from June 1997 to June 2010. Disease characteristics and clinical outcomes were compared between patients ≥70 yrs vs. <70 yrs of age.

Results: 237 patients (39%) were ≥70 yrs. Elderly patients had a higher proportion of head and neck melanomas (34% vs. 20%, p<0.001), and greater mean tumor thickness (2.4mm vs. 1.8mm, p<0.001). A greater proportion of T3 or T4 melanoma was seen in the elderly (p<0.001) as well as a greater mean number of mitotic figures: 3.6/mm² vs. 2.7/mm² (p=0.005). Despite greater mean thickness, the incidence of SLN metastases was less in the ≥70 yrs group with T3/T4 melanomas (18% vs. 33%, p=0.02). The elderly had a higher rate of local and in-transit recurrences, 14.5% vs. 3.4% at 5 yrs (p<0.001). 5 yr disease-specific mortality and overall mortality were worse for those ≥70 yrs: 16% vs. 8% (p=0.004), and 30% vs. 12% (p<0.001), respectively.

Conclusions: Elderly (≥70 yrs) melanoma patients present with thicker melanomas and a higher mitotic rate but have fewer SLN metastases. Melanoma in the elderly is more common on the head and neck. Higher incidence of local/in-transit metastases is seen among the elderly. Five-year disease-specific mortality and overall mortality are both worse for these patients.

Validation of statistical predictive models meant to select melanoma patients for sentinel lymph node biopsy

INTRODUCTION

To identify melanoma patients at sufficiently low risk of nodal metastases who could avoid sentinel lymph node biopsy (SLNB), several statistical models have been proposed based upon patient/tumor characteristics, including logistic regression, classification trees, random forests, and support vector machines. We sought to validate recently published models meant to predict sentinel node status.

METHODS

We queried our comprehensive, prospectively collected melanoma database for consecutive melanoma patients undergoing SLNB. Prediction values were estimated based upon four published models, calculating the same reported metrics: negative predictive value (NPV), rate of negative predictions (RNP), and false-negative rate (FNR).

RESULTS

Logistic regression performed comparably with our data when considering NPV (89.4 versus 93.6%); however, the model's specificity was not high enough to significantly reduce the rate of biopsies (SLN reduction rate of 2.9%). When applied to our data, the classification tree produced NPV and reduction in biopsy rates that were lower (87.7 versus 94.1 and 29.8 versus 14.3, respectively). Two published models could not be applied to our data due to model complexity and the use of proprietary software.

CONCLUSIONS

Published models meant to reduce the SLNB rate among patients with melanoma either underperformed when applied to our larger dataset, or could not be validated. Differences in selection criteria and histopathologic interpretation likely resulted in underperformance. Statistical predictive models must be developed in a clinically applicable manner to allow for both validation and ultimately clinical utility.

Lymphovascular Invasion as a Prognostic Factor in Melanoma

The prognostic significance of lymphovascular invasion (LVI) in melanoma remains controversial. Clinicopathologic data from a prospective trial of patients with melanoma were analyzed with respect to LVI. Disease-free survival and overall survival (OS) were evaluated by Kaplan-Meier (KM) analysis. Univariate and multivariate analyses were performed to evaluate factors predictive of tumor-positive sentinel nodes (SLN) and survival. A total of 2183 patients were included in this analysis; 171 (7.8%) had LVI. Median follow-up was 68 months. Factors associated with LVI included tumor thickness, ulceration, and histologic subtype ( P < 0.05). LVI was associated with a greater risk of SLN metastasis ( P < 0.05). By KM analysis, LVI was associated with worse OS ( P = 0.0009). On multivariate analysis, age, gender, thickness, ulceration, anatomic location, and SLN status were predictors of OS; however, LVI was not an independent predictor of OS. Among patients with regression, the 5-year OS rate was 49.4 per cent for patients with LVI versus 81.1 per cent for those with no LVI ( P < 0.0001). LVI is associated with a greater risk of SLN metastasis. Although LVI is not an independent predictor of OS in general, it is a powerful predictor of worse OS among patients who have evidence of regression of the primary tumor.

Outcomes in pediatric melanoma: comparing prepubertal to adolescent pediatric patients

OBJECTIVE

The aim of this study was to determine the influence of age on outcome in pediatric melanoma patients and to identify factors associated with positive lymph node status in this population.

METHODS

A retrospective review of a prospective pediatric melanoma database, using sentinel lymph node biopsy (SLNB), from 1992 to 2006, identified 109 patients with the primary diagnosis of melanoma. Patient age was dichotomized as prepubescent (<10 years of age) and adolescent (≥10-18 years of age). Factors investigated included patient race, sex, and lymph node status and tumor thickness, Spitzoid or Non-Spitzoid histology, radial growth phase, and vascular invasion. The Fisher's exact test was used to compare patient groups. Time-to-event analysis was performed using the Kaplan-Meier method.

RESULTS

There were 25 prepubescent and 84 adolescent patients. Prepubescent patients were more often non-White, had greater tumor thickness, more spitzoid tumors and more vascular invasion. Ten-year overall survival (OS) was 89% and 10-year event-free survival (EFS) was 73%. Among 57 patients who had an SLNB, prepubertal patients had a higher percentage of sentinel lymph node positivity. The odds having a positive SLNB decreased by 13% each year with increasing age. Patients with a tumor thickness ≥2.01 mm had higher odds of having a positive lymph node compared with those patients with a tumor thickness ≤1.0.

CONCLUSIONS

This is the largest known study of prepubertal melanoma patients. Although OS and EFS did not differ by age groups, younger ages showed increased risk of lymph node metastasis and thicker tumors. This suggests that the younger pediatric patients may have a disease that differs biologically from that of the older pediatric patients.

Sentinel node biopsy for melanoma: an update after two decades of experience

When detected and treated early, melanoma has an excellent prognosis. Unfortunately, as the tumor invades deeper into tissue the risk of metastatic spread to regional lymph nodes and beyond increases and the prognosis worsens significantly. Therefore, accurately detecting any regional lymphatic metastasis would significantly aid in determining a patient's prognosis and help guide his or her treatment plan. In 1991, Don Morton and colleagues presented new paradigm in diagnosing regional lymphatic involvement of tumors termed sentinel lymph node biopsy (SLNB). By mapping the regional lymph system around a tumor and tracing the lymphatic flow, a determination of the most likely lymph node or nodes the cancer will spread to first is made. Then, a limited biopsy of the most likely nodes is performed rather than a more-invasive removal of the entire local lymphatic chain. In 20 years that have followed, a great deal of information has been gained as to its accuracy, prognostic value, appropriate candidates, and its impact on regional disease control and survival. The SLNB has been shown to accurately stage regional lymph node basins in stage I and II melanoma patients with minimal morbidity. More sensitive histologic techniques are now being applied that may allow even greater accuracy in the staging of melanoma patients. Although specific percent risk thresholds are still in question, recommendation for SLNB when melanomas are 1 mm or thicker has gained wide acceptance. SLNB may also be appropriate for patients with melanomas that are between 0.76 and 1 mm thick and have ulceration, high mitotic rates, or reach a Clark level IV. Therefore, melanomas with IB or greater staging should be considered for SLNB.

Histopathological diagnostics of malignant melanoma in accordance with the recent AJCC classification 2009: Review of the literature and recommendations for general practice

BACKGROUND

TNM classifications are the basis for diagnostic and therapeutic procedures in oncology. Histopathological reports have to enable a proper indexing of tumor specific findings into recent classifications.

METHODS

A systematic review of the literature was performed to identify reports dealing with the assessment of mitotic rate and the processing and evaluation of sentinel node biopsies in malignant melanoma. On the basis of this review an expert panel of dermatopathologists and general pathologists discussed and agreed recommendations for general practice.

RESULTS

Following recommendations were agreed with a broad consensus (93-100 % agreement): The determination of the mitotic rate in primary melanoma is performed on HE slides. The evaluation of an area of 1 mm(2) is sufficient. Only dermal mitoses are considered. The counted number of mitoses is provided as an integer value. The mitotic rate shall be determined in primary melanomas of ≤1.00 mm vertical tumor thickness according to the hot-spot method and provided as an integer value in relation to an area of 1 mm(2) . The determination of the mitotic rate in the case of thicker primary melanomas is desirable. In general, for the evaluation of each sentinel lymph node, 4 slides should be prepared. For diagnostic purposes, immunohistochemistry (preferably with antibodies against S100ß, Melan A and HMB-45) should be performed in addition to HE staining. The pathology report should provide information about micro-metastases and their longest extension (one-tenth of a millimeter).

CONCLUSIONS

These recommendations are suitable for standardizing the histopathological diagnosis of malignant melanoma and for providing a common basis for clinical decisions and scientific research.

Factors predictive of the status of sentinel lymph nodes in melanoma patients from a large multicenter database

BACKGROUND

Numerous predictive factors for cutaneous melanoma metastases to sentinel lymph nodes have been identified; however, few have been found to be reproducibly significant. This study investigated the significance of factors for predicting regional nodal disease in cutaneous melanoma using a large multicenter database.

METHODS

Seventeen institutions submitted retrospective and prospective data on 3463 patients undergoing sentinel lymph node (SLN) biopsy for primary melanoma. Multiple demographic and tumor factors were analyzed for correlation with a positive SLN. Univariate and multivariate statistical analyses were performed.

RESULTS

Of 3445 analyzable patients, 561 (16.3%) had a positive SLN biopsy. In multivariate analysis of 1526 patients with complete records for 10 variables, increasing Breslow thickness, lymphovascular invasion, ulceration, younger age, the absence of regression, and tumor location on the trunk were statistically significant predictors of a positive SLN.

CONCLUSIONS

These results confirm the predictive significance of the well-established variables of Breslow thickness, ulceration, age, and location, as well as consistently reported but less well-established variables such as lymphovascular invasion. In addition, the presence of regression was associated with a lower likelihood of a positive SLN. Consideration of multiple tumor parameters should influence the decision for SLN biopsy and the estimation of nodal metastatic disease risk.

Staging and prognosis of cutaneous melanoma

Staging of cutaneous melanoma continues to evolve through identification and rigorous analysis of potential prognostic factors. In 1998, the American Joint Committee on Cancer (AJCC) Melanoma Staging Committee developed the AJCC melanoma staging database, an international integrated compilation of prospectively accumulated melanoma outcome data from several centers and clinical trial cooperative groups. Analysis of this database resulted in major revisions to the TNM staging system reflected in the sixth edition of the AJCC Cancer Staging Manual published in 2002. More recently, the committee's analysis of an updated melanoma staging database, including prospective data on more than 50,000 patients, led to staging revisions adopted in the seventh edition of the AJCC Cancer Staging Manual published in 2009. This article highlights these revisions, reviews relevant prognostic factors and their impact on staging, and discusses emerging tools that will likely affect future staging systems and clinical practice.

Thin melanoma

CONTEXT

The incidence of malignant melanoma is increasing and a preponderance of the melanomas diagnosed today are "thin in terms of Breslow criteria. Although thin melanomas, as a group, are associated with a very good prognosis, a subset of these tumors may metastasize and cause death. These cases can be identified by using prognostic models, including the "standard" American Joint Committee on Cancer criteria, and other attributes identified in follow-up studies.

OBJECTIVE

To review the history of concepts of prognostic modeling in melanoma, focusing on thin melanomas.

DATA SOURCES

Selected literature.

CONCLUSIONS

About 40 years ago, it was realized that malignant melanoma, once almost uniformly fatal, could be divided into categories with better or worse prognosis through the use of prognostic models. The first simple models, Clark levels of invasion and Breslow thickness, are still in use. Thickness remains the single most useful variable. Breslow recognized that melanomas less than 0.76 mm in thickness were associated with a very good prognosis, with no metastases in his limited initial study. The American Joint Committee on Cancer selected a cutoff of 1.0 mm, which achieves a similar result, with stage modifiers, although some metastases and deaths do occur with stage I lesions. Clark demonstrated an almost equally good prognosis for his level II invasive melanomas and recognized that most of these lesions, although invasive, lacked the ability to form tumors or to undergo mitosis in the dermis and were therefore "nontumorigenic" and "nonmitogenic" and lacked competence for metastasis. Studies of these low-risk melanomas have led to the development of criteria for earlier diagnosis and a steady, but still inadequate, improvement in prognosis for melanoma overall. Multivariable models currently can identify groups of patients within the "thin melanoma" category whose prognosis varies, from a disease-free survival of close to 100% to about 70%. Prognosis declines more or less linearly with increasing thickness, modified by ulceration, mitotic rate, and other attributes.

Prognostic significance of mitotic rate in localized primary cutaneous melanoma: an analysis of patients in the multi-institutional American Joint Committee on Cancer melanoma staging database

PURPOSE

The aim of this study was to assess the independent prognostic value of primary tumor mitotic rate compared with other clinical and pathologic features of stages I and II melanoma.

METHODS

From the American Joint Committee on Cancer (AJCC) melanoma staging database, information was extracted for 13,296 patients with stages I and II disease who had mitotic rate data available.

RESULTS

Survival times declined as mitotic rate increased. Ten-year survival ranged from 93% for patients whose tumors had 0 mitosis/mm(2) to 48% for those with ≥ 20/mm(2) (P < .001). Mean number of mitoses/mm(2) increased as the primary melanomas became thicker (1.0 for melanomas ≤ 1 mm, 3.5 for 1.01 to 2.0 mm, 7.3 for 3.01 to 4.0 mm, and 9.6 for > 8 mm). Ulceration was also associated with a higher mitotic rate; 59% of ulcerated melanomas had ≥ 5 mitoses/mm(2) compared with 16% of nonulcerated melanomas (P < .001). In a multivariate analysis of 10,233 patients, the independent predictive factors for survival in order of statistical significance were as follows: tumor thickness (χ(2) = 104.9; P < .001), mitotic rate (χ(2) = 67.0; P < .001), patient age (χ(2) = 48.2; P < .001), ulceration (χ(2) = 46.4; P < .001), anatomic site (χ(2) = 34.6; P < .001), and patient sex (χ(2) = 33.9; P < .001). Clark level of invasion was not an independent predictor of survival (χ(2) = 3.2; P = .37).

CONCLUSION

A high mitotic rate in a primary melanoma is associated with a lower survival probability. Among the independent predictors of melanoma-specific survival, mitotic rate was the strongest prognostic factor after tumor thickness.

Age as a key factor influencing metastasizing patterns and disease-specific survival after sentinel lymph node biopsy for cutaneous melanoma

In our study, we investigated the impact of the constitutional factor age on the clinical courses of melanoma patients with sentinel lymph node (SLN) biopsy. Descriptive statistics, Kaplan-Meier estimates, logistic regression analysis and the Cox proportional hazards model were used to study a population of 2,268 consecutive patients from three German melanoma centers. Younger age was significantly related to less advanced primary tumors. Nevertheless, patients younger than 40 years of age had a twofold risk of being SLN-positive (p < 0.000001). Of the young patients with primary melanomas with a thickness of 0.76 mm to 1.0 mm, 19.7% were SLN-positive. Using multivariate analysis, younger age, increasing Breslow thickness, ulceration and male sex were significantly related to a higher probability of SLN-metastasis. During follow-up, older patients displayed a significantly increased risk of in-transit recurrences (p = 0.000002) and lymph node recurrences (p = 0.0004). With respect to melanoma specific overall survival the patient's age was highly significant in the multivariate analysis. The unfavorable effect of being older was significant in the subgroups with positive and negative SLNs. Age remained also significant for the survival after the onset of distant metastases (p = 0.002). In conclusion, the patient's age is a strong and independent predictor of melanoma-specific survival in patients with localized melanomas, in patients with positive SLNs and after the onset of distant metastases. Younger patients have a better prognosis despite their higher probability of SLN metastasis. Older patients are less frequently SLN-positive but have a higher risk of loco-regional recurrence.

Features predicting sentinel lymph node positivity in Merkel cell carcinoma

PURPOSE

Merkel cell carcinoma (MCC) is a relatively rare, potentially aggressive cutaneous malignancy. We examined the clinical and histologic features of primary MCC that may correlate with the probability of a positive sentinel lymph node (SLN).

METHODS

Ninety-five patients with MCC who underwent SLN biopsy at the University of Michigan were identified. SLN biopsy was performed on 97 primary tumors, and an SLN was identified in 93 instances. These were reviewed for clinical and histologic features and associated SLN positivity. Univariate associations between these characteristics and a positive SLN were tested for by using either the χ(2) or the Fisher's exact test. A backward elimination algorithm was used to help create a best multiple variable model to explain a positive SLN.

RESULTS

SLN positivity was significantly associated with the clinical size of the lesion, greatest horizontal histologic dimension, tumor thickness, mitotic rate, and histologic growth pattern. Two competing multivariate models were generated to predict a positive SLN. The histologic growth pattern was present in both models and combined with either tumor thickness or mitotic rate.

CONCLUSION

Increasing clinical size, increasing tumor thickness, increasing mitotic rate, and infiltrative tumor growth pattern were significantly associated with a greater likelihood of a positive SLN. By using the growth pattern and tumor thickness model, no subgroup of patients was predicted to have a lower than 15% to 20% likelihood of a positive SLN. This suggests that all patients presenting with MCC without clinical evidence of regional lymph node disease should be considered for SLN biopsy.

Does mitotic rate predict sentinel lymph node metastasis or survival in patients with intermediate and thick melanoma?

BACKGROUND

The significance of mitotic rate (MR) in melanoma remains controversial.

METHODS

In this retrospective analysis of a prospective randomized trial that included patients with melanoma of 1.0 mm or greater, all patients underwent wide excision and sentinel node (sentinel lymph node [SLN]) biopsy. Univariate and multivariate analyses were performed to evaluate factors predictive of disease-free survival (DFS) and overall survival (OS).

RESULTS

A total of 551 patients had MR reported. A cut-off point of 6 mitoses/mm(2) best discriminated DFS and OS: 455 patients (82.6%) had MR less than 6/mm(2). SLN were tumor-positive in 14.7% of low MR versus 31.3% of high MR patients (P = .0003). There were significant differences in DFS (P = .0014) and OS (P = .0002) between the 2 groups, however, MR failed to remain significant in the multivariate model.

CONCLUSIONS

MR is weakly predictive of SLN status but it is not an independent predictor of survival for melanomas 1.0 mm or thicker.

Useof anti-phosphohistone H3 immunohistochemistry to determine mitotic rate in thin melanoma

The seventh edition of the American Joint Committee on Cancer (AJCC) melanoma staging system, slated for release in 2010, will introduce mitotic rate (MR) as one of the primary criteria for staging thin melanoma (< or = 1.0 mm). Accurate counts are essential because the finding of a single mitotic figure (MF) will alter the staging and management of these patients. The traditional manner of counting of mitotic figures (MFs) using a X40 objective is time consuming and prone to inter- and intraobserver variability. We employed an antibody to phosphohistone H3 (pHH3, ser10) that labels MFs in all stages of mitosis, to evaluate mitotic counts at X20 in tissue sections from 30 melanoma patients with thin lesions 0.45 to 1.2 mm in depth, and compared results with routine hematoxylin and eosin (H&E) in a double-blind fashion. The mean MR was 1.63 by antipHH3, and 0.67 for H&E, representing a mean increase of 243%. The Spearman correlation coefficient for MR in H&E and anti-pHH3 sections was 0.88 (P < 0.0001). When melanomas were designated as "mitotically active," if the MR by anti-pHH3 was > or = 2 and > or = 1 by H&E, the correlation coefficient increased to 1.0. No thin melanomas were mitotically inactive on anti-pHH3 but active on H&E. Results indicate that anti-pHH3 is a useful immunostain for labeling melanocytes in mitosis. Subsequent studies will be needed confirm the accuracy of this staining technique, which has the potential to be used as a screening method for counting MFs before conventional H&E methodology in the microstaging of thin melanoma.

Melanoma sentinel node biopsy and prediction models for relapse and overall survival

BACKGROUND

To optimise predictive models for sentinal node biopsy (SNB) positivity, relapse and survival, using clinico-pathological characteristics and osteopontin gene expression in primary melanomas.

METHODS

A comparison of the clinico-pathological characteristics of SNB positive and negative cases was carried out in 561 melanoma patients. In 199 patients, gene expression in formalin-fixed primary tumours was studied using Illumina's DASL assay. A cross validation approach was used to test prognostic predictive models and receiver operating characteristic curves were produced.

RESULTS

Independent predictors of SNB positivity were Breslow thickness, mitotic count and tumour site. Osteopontin expression best predicted SNB positivity (P=2.4 × 10⁻⁷), remaining significant in multivariable analysis. Osteopontin expression, combined with thickness, mitotic count and site, gave the best area under the curve (AUC) to predict SNB positivity (72.6%). Independent predictors of relapse-free survival were SNB status, thickness, site, ulceration and vessel invasion, whereas only SNB status and thickness predicted overall survival. Using clinico-pathological features (thickness, mitotic count, ulceration, vessel invasion, site, age and sex) gave a better AUC to predict relapse (71.0%) and survival (70.0%) than SNB status alone (57.0, 55.0%). In patients with gene expression data, the SNB status combined with the clinico-pathological features produced the best prediction of relapse (72.7%) and survival (69.0%), which was not increased further with osteopontin expression (72.7, 68.0%).

CONCLUSION

Use of these models should be tested in other data sets in order to improve predictive and prognostic data for patients.

Sentinel lymph node biopsy and melanoma: 2010 update Part II

This article will discuss the evidence for and against the therapeutic efficacy of early removal of potentially affected lymph nodes, morbidity associated with sentinel lymph node biopsy and completion lymphadenectomy, current guidelines regarding patient selection for sentinel lymph node biopsy, and the remaining questions that ongoing clinical trials are attempting to answer. The Sunbelt Melanoma Trial and the Multicenter Selective Lymphadenectomy Trials I and II will be discussed in detail.

LEARNING OBJECTIVES

At the completion of this learning activity, participants should be able to discuss the data regarding early surgical removal of lymph nodes and its effect on the overall survival of melanoma patients, be able to discuss the potential benefits and morbidity associated with complete lymph node dissection, and to summarize the ongoing trials aimed at addressing the question of therapeutic value of early surgical treatment of regional lymph nodes that may contain micrometastases.

Presence of tumor-infiltrating lymphocytes and a dominant nodule within primary melanoma are prognostic factors for relapse-free survival of patients with thick (t4) primary melanoma: pathologic analysis of the e1690 and e1694 intergroup trials

Lymphocytic infiltration of primary cutaneous melanoma has been demonstrated to be of prognostic significance. Tumor infiltrating lymphocytes (TILs) were evaluated on histologic sections of pT4 primary cutaneous melanoma from 293 patients, accrued in protocols 1690 and 1694 of the Eastern Cooperative Oncology Group. Data for the 60-month follow-up were available. Statistical analysis of the pathologic data evaluated the correlation of regional lymph node metastasis and response to interferon therapy, overall survival, and relapse-free survival. In multivariate analysis, there was significant correlation of the presence of TILs and improved survival. The presence of TILs did not affect the survival of patients treated with interferon alfa-2b. Presence of a localized dominant tumor nodule within the primary tumor had an adverse effect on relapse-free survival (P = .044) that was also marginally present for overall survival (P = .112). The presence of TILs has prognostic but not predictive value, and the presence of a dominant nodule in the primary lesion represents a new adverse prognostic factor that should be incorporated in the evaluation of primary melanoma. This study confirmed the importance of tumor ulceration and the number of positive lymph nodes on outcome.

Predictors of occult nodal metastasis in patients with thin melanoma

HYPOTHESIS

Thin primary lesions are largely responsible for the rapid increase in melanoma incidence, making identification of appropriate candidates for nodal staging in this group critically important. We hypothesized that common clinical variables may accurately estimate the risk of nodal metastasis after wide excision and determine the need for sentinel node biopsy.

DESIGN

Review of prospectively acquired data in a large melanoma database.

SETTING

A tertiary referral center.

PATIENTS

A total of 2211 patients with thin melanoma treated by wide local excision alone were identified in the database between January 1, 1971, and December 31, 2005. Of those, 1732 met entry criteria.

MAIN OUTCOME MEASURES

We examined the rate of regional nodal recurrence and the impact of clinical and demographic variables by univariate and multivariate analyses.

RESULTS

The overall nodal recurrence rate was 2.9%; median time to recurrence was 38.3 months. Univariate analysis of 1732 patients identified male sex (P < .001), increased Breslow thickness (P < .001), and increased Clark level (P < .001) as significant for nodal recurrence. Multivariate analysis identified male sex (hazard ratio, 3.5; 95% confidence interval, 1.8-7.0; P < .001), younger age (0.45; 0.24-0.86; P = .001), and increased Breslow thickness (2.5; 1.6-3.7; categorical P < .001) as significant for nodal recurrence. The Clark level was no longer significant (P = .63). Breslow thickness, age, and sex were used to develop a scoring system and nomogram for the risk of nodal involvement. Predictions ranged from 0.1% in the lowest-risk group to 17.4% in the highest-risk group.

CONCLUSIONS

Many patients with thin melanoma will have nodal recurrence after wide excision alone. Three simple clinical variables may be used to estimate recurrence risk and select patients for sentinel node biopsy.