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.

Completion Lymph Node Dissection Based on Risk of Nonsentinel Metastasis in Cutaneous Melanoma of the Head and Neck

Objective

Theoretically, completion lymph node dissection (CNLD) should have the lowest benefit in the absence of nonsentinel lymph node (NSLN) metastases. For this reason, substantial research efforts have attempted to define specific criteria that are associated with a low-enough risk of NSLN positivity so that CLND can be deferred. Our objectives were (1) to identify features associated with low risk of NSLN positivity in sentinel lymph node–positive cutaneous melanoma of the head and neck (CMHN) and (2) to analyze the effect of CLND on 5-year disease-specific survival (DSS) among subgroups stratified by risk of NSLN metastasis.

Study Design

Retrospective analysis of population-based data.

Setting

SEER database.

Subjects and Methods

Patients with sentinel lymph node–positive CMHN were categorized according to lymph node treatment following sentinel lymph node biopsy (SLNB): 210 underwent CLND and 140 deferred. Clinicopathologic characteristics and survival were compared between SLNB+CLND and SLNB-only groups. Survival analyses were stratified by age and characteristics associated with NSLN positivity.

Results

Minimal tumor thickness and nonulceration were associated with lowest risk of positive NSLN ( P < .025). In the subgroup with the lowest risk of metastasis, patients aged <60 years who underwent CLND+SLNB had markedly better DSS than those receiving SLNB only (>90% vs <25%; P < .0025). Paradoxically, in subgroups with a higher risk of NSLN metastasis, DSS was similar whether CLND was performed or not ( P > .25).

Conclusions

Selecting patients for CLND according to risk of NSLN metastasis may be a suboptimal strategy for improving DSS. We believe that CLND should not be withheld on the basis of “low risk” features in CMHN.

Popliteal sentinel lymph node involvement in melanoma patients

BACKGROUND

Sentinel lymph nodes (SLN) in popliteal basins are rare, and there is controversy in literature regarding their origin, management, and outcomes.

OBJECTIVES

To correlate clinical and pathological features of popliteal basin drainage and analyze the impact of popliteal lymph node drainage on survival.

MATERIALS AND METHODS

Retrospective analysis of SLN biopsies performed at a single institution between 2000 and 2010.

RESULTS

SLN biopsies were performed in 254 patients with melanoma in lower limbs, 247 of which were evaluated. In this group, there were 59 patients (24%) with a positive SLN. Twenty-seven cases (11%) presented with popliteal drainage, one of which lacked concurrent groin drainage. Among these 27 patients, three (11%) had popliteal metastasis, one of which had exclusive involvement of this basin. Popliteal drainage was associated with worse 5-year disease-free survival (DFS) (P = 0.028) but not 5-year overall survival (OS) (P = 0.219) in univariate analysis. In multivariate analysis, Breslow thickness, mitotic index, and positive SLN were prognostic factors for DFS. Only mitotic index correlated significantly with OS (P = 0.044).

CONCLUSIONS

Popliteal drainage seems to be associated with worse prognostic features of the primary tumor.

Melanoma

Melanoma is a common cancer in the Western world with an increasing incidence. Sun exposure is still considered to be the major risk factor for melanoma. The prognosis of patients with malignant (advanced-stage) melanoma differs widely between countries, but public campaigns advocating early detection have led to significant reductions in mortality rates. As well as sun exposure, distinct genetic alterations have been identified as associated with melanoma. For example, families with melanoma who have germline mutations in CDKN2A are well known, whereas the vast majority of sporadic melanomas have mutations in the mitogen-activated protein kinase cascade, which is the pathway with the highest oncogenic and therapeutic relevance for this disease. BRAF and NRAS mutations are typically found in cutaneous melanomas, whereas KIT mutations are predominantly observed in mucosal and acral melanomas. GNAQ and GNA11 mutations prevail in uveal melanomas. Additionally, the PI3K-AKT-PTEN pathway and the immune checkpoint pathways are important. The finding that programmed cell death protein 1 ligand 1 (PDL1) and PDL2 are expressed by melanoma cells, T cells, B cells and natural killer cells led to the recent development of programmed cell death protein 1 (PD1)-specific antibodies (for example, nivolumab and pembrolizumab). Alongside other new drugs - namely, BRAF inhibitors (vemurafenib and dabrafenib) and MEK inhibitors (trametinib and cobimetinib) - these agents are very promising and have been shown to significantly improve prognosis for patients with advanced-stage metastatic disease. Early signs are apparent that these new treatment modalities are also improving long-term clinical benefit and the quality of life of patients. This Primer summarizes the current understanding of melanoma, from mechanistic insights to clinical progress. For an illustrated summary of this Primer, visit: http://go.nature.com/vX2N9s.

Sentinel lymph node mapping for malignant melanoma of the external auditory canal

We describe a novel technique for sentinel lymph node mapping and biopsy of a primary cutaneous malignant melanoma in the medial portion of the external auditory canal. The approach is illustrated through a case report and technical description of a procedure performed under general anesthesia on a 19-year-old female patient. Due to the hidden and sensitive location of the primary tumor in the medial external auditory canal, the lymphoscintigraphy injection had to be performed by the surgeon immediately prior to the resection of her cT2aN0M0 lesion. Final pathology revealed clear margins at the primary site resection and 2 intraparotid sentinel lymph nodes with microscopic foci of metastatic malignant melanoma, which led to further surgical management. A completion left parotidectomy and neck dissection yielded no additional metastatic disease in the fifty-five nodes that were evaluated. Using this technique, sentinel lymph node mapping and biopsy accurately predicted the highest risk lymph nodes for the primary lesion of the medial portion of the external auditory canal.

Comparative effectiveness in melanoma

The worldwide incidence of melanoma continues to rise. It is a leading cause of cancer death and the second leading cause of loss of productive years of life. Although the diagnosis of melanoma is straightforward, there remain many controversies regarding treatment and surveillance. This chapter addresses important questions in melanoma treatment such as sentinel lymph node biopsy, what to do with a positive sentinel lymph node, margins of resection for melanoma, radiation for primary, nodal and metastatic melanoma, and routine use imaging. Through this chapter, the evidence for these controversial subjects and the barriers to resolution will be elucidated.

[Sentinel node in melanoma and breast cancer. Current considerations]

The main objectives of sentinel node (SN) biopsy is to avoid unnecessary lymphadenectomies and to identify the 20-25% of patients with occult regional metastatic involvement. This technique reduces the associated morbidity from lymphadenectomy and increases the occult lymphatic metastases identification rate by offering the pathologist the or those lymph nodes with the highest probability of containing metastatic cells. Pre-surgical lymphoscintigraphy is considered a "road map" to guide the surgeon towards the sentinel nodes and to localize unpredictable lymphatic drainage patterns. The SPECT/CT advantages include a better SN detection rate than planar images, the ability to detect SNs in difficult to interpret studies, better SN depiction, especially in sites closer to the injection site and better anatomic localization. These advantages may result in a change in the patient's clinical management both in melanoma and breast cancer. The correct SN evaluation by pathology implies a tumoral load stratification and further prognostic implication. The use of intraoperative imaging devices allows the surgeon a better surgical approach and precise SN localization. Several studies reports the added value of such devices for more sentinel nodes excision and a complete monitoring of the whole procedure. New techniques, by using fluorescent or hybrid tracers, are currently being developed.

Electron paramagnetic resonance: a powerful tool to support magnetic resonance imaging research

The purpose of this paper is to describe some of the areas where electron paramagnetic resonance (EPR) has provided unique information to MRI developments. The field of application mainly encompasses the EPR characterization of MRI paramagnetic contrast agents (gadolinium and manganese chelates, nitroxides) and superparamagnetic agents (iron oxide particles). The combined use of MRI and EPR has also been used to qualify or disqualify sources of contrast in MRI. Illustrative examples are presented with attempts to qualify oxygen sensitive contrast (i.e. T1 - and T2 *-based methods), redox status or melanin content in tissues. Other areas are likely to benefit from the combined EPR/MRI approach, namely cell tracking studies. Finally, the combination of EPR and MRI studies on the same models provides invaluable data regarding tissue oxygenation, hemodynamics and energetics. Our description will be illustrative rather than exhaustive to give to the readers a flavour of 'what EPR can do for MRI'.

Outcome following sentinel node biopsy plus wide local excision versus wide local excision only for primary cutaneous melanoma: analysis of 5840 patients treated at a single institution

OBJECTIVE

Worldwide, sentinel node biopsy (SNB) is now a standard staging procedure for most patients with melanomas 1 mm or more in thickness, but its therapeutic benefit is not clear, pending randomized trial results. This study sought to assess the therapeutic benefit of SNB in a large, nonrandomized patient cohort.

METHODS

Patients with primary melanomas 1.00 mm or more thick or with adverse prognostic features treated with wide local excision (WLE) at a single institution between 1992 and 2008 were identified. The outcomes for those who underwent WLE plus SNB (n = 2909) were compared with the outcomes for patients in an observation (OBS) group who had WLE only (n = 2931). Median follow-up was 42 months.

RESULTS

Melanoma-specific survival (MSS) was not significantly different for patients in the SNB and OBS groups. However, a stratified univariate analysis of MSS for different thickness subgroups indicated a significantly better MSS for SNB patients with T2 and T3 melanomas (>1.0 to 4.0 mm thick) (P = 0.011), but this was not independently significant in multivariate analysis. Compared with OBS patients, SNB patients demonstrated improved disease-free survival (DFS) (P < 0.001) and regional recurrence-free survival (P < 0.001). There was also an improvement in distant metastasis-free survival (DMFS) for SNB patients with T2 and T3 melanomas (P = 0.041).

CONCLUSIONS

In this study, the outcome for the overall cohort after WLE alone did not differ significantly from the outcome after additional SNB. However, the outcome for the subgroup of patients with melanomas more than 1.0 to 4.0 mm in thickness was improved if they had a SNB, with significantly improved disease-free and DMFS.

Is sentinel lymph node biopsy the standard of care for cutaneous head and neck melanoma?

OBJECTIVES/HYPOTHESIS

Sentinel lymph node biopsy (SLNB) is considered one of the most important melanoma advancements to date. Since its inception in 1992, a plethora of data and associated controversies has emerged leading to the question: Is SLNB considered the standard of care for head and neck (HN) cutaneous melanoma?

STUDY DESIGN

English literature (1990-2014) review.

METHODS

The PubMed database search was conducted using key terms "melanoma" and "sentinel node." This review included both dedicated HN SLNB studies and larger prospective SLNB studies, in which HN patients were included among the cohort. Bibliography cross-referencing was conducted to ensure a comprehensive search.

RESULTS

SLNB is safe and accurate in the HN region. Review of large prospective SLNB trials identified the pathologic status of the SLN as the most important prognostic factor for recurrence and survival. Early lymphadenectomy following a positive SLNB imparts a survival benefit.

CONCLUSIONS

Our review of the current literature suggests that SLNB is the standard of care for selected cases of HN cutaneous melanoma. It is now incorporated into the American Joint Committee on Cancer staging system, the National Comprehensive Cancer Network practice guidelines, and numerous national and international consensus statements.

Mapping lymph nodes in cancer management - role of (99m)Tc-tilmanocept injection

Two decades ago, lymphatic mapping of sentinel lymph nodes (SLN) was introduced into surgical cancer management and was termed sentinel node navigated surgery. Although this technique is now routinely performed in the management of breast cancer and malignant melanoma, it is still under investigation for use in other cancers. The radioisotope technetium (^99mTc) and vital blue dyes are among the most widely used enhancers for SLN mapping, although near-infrared fluorescence imaging of indocyanine green is also becoming more commonly used. ^99mTc-tilmanocept is a new synthetic radioisotope with a relatively small molecular size that was specifically developed for lymphatic mapping. Because of its small size, ^99mTc-tilmanocept quickly migrates from its site of injection and rapidly accumulates in the SLN. The mannose moieties of ^99mTc-tilmanosept facilitate its binding to mannose receptors (CD206) expressed in reticuloendothelial cells of the SLN. This binding prevents transit to second-echelon lymph nodes. In Phase III trials of breast cancer and malignant melanoma, and Phase II trials of other malignancies, ^99mTc-tilmanocept had superior identification rates and sensitivity compared with blue dye. Trials comparing ^99mTc-tilmanocept with other ^99mTc-based agents are required before it can be routinely used in clinical settings.

Update and Review on the Surgical Management of Primary Cutaneous Melanoma

The surgical management of malignant melanoma historically called for wide excision of skin and subcutaneous tissue for any given lesion, but has evolved to be rationally-based on pathological staging. Breslow and Clark independently described level and thickness as determinant in prognosis and margin of excision. The American Joint Committee of Cancer (AJCC) in 1988 combined features from each of these histologic classifications, generating a new system, which is continuously updated and improved. The National Comprehensive Cancer Network (NCCN) has also combined several large randomized prospective trials to generate current guidelines for melanoma excision as well. In this article, we reviewed: (1) Breslow and Clark classifications, AJCC and NCCN guidelines, the World Health Organization's 1988 study, and the Intergroup Melanoma Surgical Trial; (2) Experimental use of Mohs surgery for in situ melanoma; and (3) Surgical margins and utility and indications for sentinel lymph node biopsy (SLNB) and lymphadenectomy. Current guidelines for the surgical management of a primary melanoma of the skin is based on Breslow microstaging and call for cutaneous margins of resection of 0.5 cm for MIS, 1.0 cm for melanomas ≤1.0 mm thick, 1-2 cm for melanoma thickness of 1.01-2 mm, 2 cm margins for melanoma thickness of 2.01-4 mm, and 2 cm margins for melanomas >4 mm thick. Although the role of SLNB, CLND, and TLND continue to be studied, current recommendations include SLNB for Stage IB (includes T1b lesions ≤1.0 with the adverse features of ulceration or ≥1 mitoses/mm²) and Stage II melanomas. CLND is recommended when sentinel nodes contain metastatic deposits.

Management of regional metastatic disease in head and neck cutaneous malignancy. 2. Cutaneous malignant melanoma

This is the second of 2 articles giving an overview of the current evidence for management of the neck and parotid in cutaneous cancers of the head and neck. We discuss cutaneous malignant melanoma and review the latest evidence for management of the regional nodes.

Incidence and location of positive nonsentinel lymph nodes in head and neck melanoma

BACKGROUND

The complex lymphatic drainage in the head and neck makes sentinel lymph node biopsy (SLNB) for melanomas in this region challenging. This study describes the incidence, and location of additional positive nonsentinel lymph nodes (NSLN) in patients with cutaneous head and neck melanoma following a positive SLNB.

METHODS

A retrospective review was performed using a single institution prospective database. Patients with a primary melanoma in the head or neck with a positive cervical SLNB were identified. The lymphadenectomy specimen was divided intraoperatively into lymph node levels I-V, and NSLN status determined for each level.

RESULTS

Of 387 patients with melanoma of the head and neck who underwent cervical SLNB, 54 had a positive SLN identified (14%). Thirty six patients (67%) underwent immediate completion lymph node dissection (CLND) of whom eight patients (22%) had a positive NSLN. The remaining 18 patients (33%) did not undergo CLND and were observed. Half of positive NSLNs (50%) were in the same lymph node level as the SLN and 33% were in an immediately adjacent level; only two patients were found to have NSLNs in non-adjacent levels. The only factor predictive of NSLN involvement was the size of the tumor deposit in the SLN>0.2 mm (p = 0.05). Superficial parotidectomy at CLND revealed metastatic melanoma only in patients with a positive parotid SLN.

CONCLUSIONS

A positive NLSN was identified in 22% of patients undergoing CLND after a positive SLNB. The majority of positive NSLNs are found within or immediately adjacent to the nodal level containing the SLN.

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.

Limitations of lymph node ratio, evidence-based benchmarks, and the importance of a thorough lymph node dissection in melanoma

BACKGROUND

Stage III melanoma is currently stratified by number of lymph nodes (LNs) involved. However, given the variability of LN retrieval counts we hypothesize that lymph node ratio (LNR) may also provide prognostic information.

METHODS

Retrospective cohort study of 411 patients with stage III melanoma were divided into two groups based on LNR (<0.15, n = 291 and ≥0.15, n = 120).

RESULTS

In multivariate analysis N stage (N3 vs. N1, hazard ratio [HR] = 2.13, p < 0.001), extranodal extension (HR = 1.92, p = 0.002), macrometastasis (HR = 1.70, p = 0.005), non-SLN involvement (HR = 1.65, p = 0.005), risk of N2 disease exceeding 35 % (HR = 1.51, p = 0.03), and LNR ≥0.15 (HR = 1.46, p = 0.03) were associated with overall survival (OS). LNR failed to further stratify stage III melanoma; however, the number of LNs examined was an independent prognostic factor. Patients who had >8 inguinal, >15 axillary, or >20 cervical LNs examined had fewer same nodal basin recurrences (26 [8 %] vs. 20 [20 %], p = 0.0009) and for N1 patients an improved OS (3-year OS 84 % vs. 76 %, 10-year OS 53 % vs. 34 %, p = 0.06) compared with N1 patients who had fewer LNs examined.

CONCLUSIONS

LNR is an important prognostic factor in stage III melanoma; however, it was not independent over the current AJCC TNM staging system. Diligence by the surgeon and pathologist to retrieve and examine >8 inguinal, >15 axillary, or >20 cervical LNs is associated with fewer same nodal basin recurrences and improved survival and is critical to reliable prognostication.

Desmoplastic melanoma: is there a role for sentinel lymph node biopsy?

BACKGROUND

The utility of sentinel lymph node biopsy (SLNB) for desmoplastic melanoma (DM) is debated. We describe a large single-institution experience with SLNB for DM to determine clinicopathologic factors predictive of SLN metastasis.

METHODS

Retrospective review identified 205 patients with DM who underwent SLNB from 1992 to 2010. Clinicopathologic characteristics were correlated with SLN status and outcome.

RESULTS

Median age was 66 years, and 69 % of patients were male. Median Breslow thickness was 3.7 mm. In 128 cases (62 %), histologic subtype data was available; 61 cases (47.7 %) were mixed and 67 cases (52.3 %) were pure DM. A positive SLN was found in 28 cases (13.7 %); 24.6 % of mixed and 9 % of pure DM had SLN metastases. Multivariable analysis demonstrated that after controlling for age, histologic subtype correlated with SLN status [odds ratio: 3.0 for mixed vs pure, 95 % confidence interval: 1.1-8.7; p < .05]. Completion lymph node dissection was performed in 24 of 28 positive SLN patients with 16.7 % of cases having additional nodal disease. After a median follow-up of 6.3 years, 38 patients developed recurrence and 61 patients died. Positive SLN patients had a significantly higher risk of melanoma-related death compared with negative SLN patients (p = .01).

CONCLUSIONS

The overall risk for SLN metastasis for DM is 13.7 % and is significantly higher for mixed (24.6 %) compared with pure (9.0 %) DM. We believe that these rates are sufficient to justify consideration of SLNB for both histologic variants, especially since detection of SLN disease appears to predict a higher risk for melanoma-related death.