The challenge of defining guidelines for sentinel lymph node biopsy in patients with thin primary cutaneous melanomas

Analysis of malignant melanoma risk and outcomes in solid organ transplant recipients: Assessment of transplant candidacy and the potential role of checkpoint inhibitors

Malignant melanoma (MM) causes tremendous morbidity and mortality in the solid organ transplant population and may arise in three different clinical scenarios: (1) pretransplant melanoma; (2) de novo melanoma post transplantation and (3) donor-derived melanoma. This manuscript primarily addresses the first two scenarios with respect to the evaluation and management of pretransplant MM, consideration of transplant candidacy and the occurrence and management of de novo MM post transplantation. The authors outline current evidence describing risks associated with pre-transplant melanoma to support recently established expert opinion for transplant candidacy.

Clinicopathological Features, Staging, and Current Approaches to Treatment in High-Risk Resectable Melanoma

The incidence of melanoma in the United States has been increasing over the past several decades. Prognosis largely depends on disease stage, with 5-year melanoma-specific survival ranging from as high as 99% in patients with stage I disease to less than 10% for some patients with stage IV (distant metastatic) disease. Fortunately, in the last 5-10 years, there have been remarkable treatment advances for patients with high-risk resectable melanoma, including approval of targeted and immune checkpoint blockade therapies. In addition, results of recent clinical trials have confirmed the importance of sentinel lymph node biopsy and continue to refine the approach to regional lymph node basin management. Lastly, the melanoma staging system was revised in the eighth edition AJCC Cancer Staging Manual, which was implemented on January 1, 2018. Here we discuss these changes and the clinicopathological features that confer high risk for locoregional and distant disease relapse and poor survival. Implications regarding the management of melanoma in the metastatic and adjuvant settings are discussed, as are future directions for neoadjuvant therapies.

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

BACKGROUND

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Predictive Value of Sentinel Lymph Node Biopsy in Cutaneous Squamous Cell Carcinoma Based on the AJCC-8 and Brigham and Women's Hospital Staging Criteria

BACKGROUND

Recommendations on when to perform sentinel lymph node (SLN) biopsy in cutaneous squamous cell carcinoma (cSCC) are lacking despite the tumor's clear predilection for lymphatic spread.

OBJECTIVE

To analyze the frequency of SLN metastasis in published series of cSCC in the context of the eighth edition of the American joint Committee on Cancer (AJCC-8) and the Brigham and Women's Hospital (BWH) staging criteria.

METHODS

Systematic review of studies of patients with cSCC who underwent SLN biopsy that described biopsy results.

RESULTS

In total, 153 patients with 24 positive SLN biopsies (15.7%) were included. Based on the AJCC-8 criteria positivity rates in the T2 and T3 categories were 8.3% (1/12 patients) and 25% (8/32), respectively. Using the BWH system there were, 2/33 in category T2a (6.5%), and 5/17 in category T2b (29.8%). On applying the same criteria to tumors of the trunk and extremities the results were similar.

CONCLUSION

It would seem reasonable to recommend SLN biopsy for patients with AJCC-8 Stage T3+ disease or BWH Stage T2b/T3 disease. Both the AJCC-8 and the BWH systems would appear to be useful for staging cSCC of the trunk and extremities.

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

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

Melanoma staging: Evidence-based changes in the American Joint Committee on Cancer eighth edition cancer staging manual

Answer questions and earn CME/CNE To update the melanoma staging system of the American Joint Committee on Cancer (AJCC) a large database was assembled comprising >46,000 patients from 10 centers worldwide with stages I, II, and III melanoma diagnosed since 1998. Based on analyses of this new database, the existing seventh edition AJCC stage IV database, and contemporary clinical trial data, the AJCC Melanoma Expert Panel introduced several important changes to the Tumor, Nodes, Metastasis (TNM) classification and stage grouping criteria. Key changes in the eighth edition AJCC Cancer Staging Manual include: 1) tumor thickness measurements to be recorded to the nearest 0.1 mm, not 0.01 mm; 2) definitions of T1a and T1b are revised (T1a, <0.8 mm without ulceration; T1b, 0.8-1.0 mm with or without ulceration or <0.8 mm with ulceration), with mitotic rate no longer a T category criterion; 3) pathological (but not clinical) stage IA is revised to include T1b N0 M0 (formerly pathologic stage IB); 4) the N category descriptors "microscopic" and "macroscopic" for regional node metastasis are redefined as "clinically occult" and "clinically apparent"; 5) prognostic stage III groupings are based on N category criteria and T category criteria (ie, primary tumor thickness and ulceration) and increased from 3 to 4 subgroups (stages IIIA-IIID); 6) definitions of N subcategories are revised, with the presence of microsatellites, satellites, or in-transit metastases now categorized as N1c, N2c, or N3c based on the number of tumor-involved regional lymph nodes, if any; 7) descriptors are added to each M1 subcategory designation for lactate dehydrogenase (LDH) level (LDH elevation no longer upstages to M1c); and 8) a new M1d designation is added for central nervous system metastases. This evidence-based revision of the AJCC melanoma staging system will guide patient treatment, provide better prognostic estimates, and refine stratification of patients entering clinical trials. CA Cancer J Clin 2017;67:472-492. © 2017 American Cancer Society.

Breslow Thickness Measurements of Melanomas Around American Joint Committee on Cancer Staging Cut-Off Points: Imprecision and Terminal Digit Bias Have Important Implications for Staging and Patient Management

BACKGROUND

Breslow thickness is the most important prognostic factor in patients with clinically localized primary cutaneous melanomas, and its accuracy has important implications for staging and management. A review of the Melanoma Institute Australia database and population-based data for the state of New South Wales, Australia, found an unexpectedly large number of melanomas reported as being exactly 1.0 mm thick. We sought to determine possible causes for this biologically implausible finding.

METHODS

The tumor thickness of 125 invasive cutaneous melanomas with a recorded Breslow thickness of 0.9-1.1 mm was remeasured and recorded by two pathologists.

RESULTS

Concordance of measurements between the two pathologists was high (intraclass correlation coefficient 0.816, 95 % CI 0.733-0.873). The original measurements showed clustering at 0.9, 1.0, and 1.1 mm, whereas the review measurements did not. The original measurements staged 84 cases (72 %) as T1 and 33 (28 %) as T2, while the reviewed measurements staged 58 cases (50 %) as T1 and 59 (50 %) as T2 (p < 0.001).

CONCLUSIONS

Our study demonstrated imprecision in Breslow thickness measurements and its significant impact on staging. Two potential sources of imprecision are failure to follow standardized thickness measurement guidelines and the phenomenon of terminal digit bias, not previously identified as a problem in this field. Educating pathologists about this phenomenon and the importance of utilizing ocular micrometers may improve the precision of melanoma thickness measurements around critical staging cut-off points. Clinicians must also be educated to appreciate that there is an inevitable margin of error with Breslow thickness measurements that should be considered when making management decisions.

The inextricable axis of targeted diagnostic imaging and therapy: An immunological natural history approach

In considering the challenges of approaches to clinical imaging, we are faced with choices that sometimes are impacted by rather dogmatic notions about what is a better or worse technology to achieve the most useful diagnostic image for the patient. For example, is PET or SPECT most useful in imaging any particular disease dissemination? The dictatorial approach would be to choose PET, all other matters being equal. But is such a totalitarian attitude toward imaging selection still valid? In the face of new receptor targeted SPECT agents one must consider the remarkable specificity and sensitivity of these agents. (99m)Tc-Tilmanocept is one of the newest of these agents, now approved for guiding sentinel node biopsy (SLNB) in several solid tumors. Tilmanocept has a Kd of 3×10(-11)M, and it specificity for the CD206 receptor is unlike any other agent to date. This coupled with a number of facts, that specific disease-associated macrophages express this receptor (100 to 150 thousand receptors), that the receptor has multiple binding sites for tilmanocept (>2 sites per receptor) and that these receptors are recycled every 15 min to bind more tilmanocept (acting as intracellular "drug compilers" of tilmanocept into non-degraded vesicles), gives serious pause as to how we select our approaches to diagnostic imaging. Clinically, the size of SLNs varies greatly, some, anatomically, below the machine resolution of SPECT. Yet, with tilmanocept targeting, the SLNs are highly visible with macrophages stably accruing adequate (99m)Tc-tilmanocept counting statistics, as high target-to-background ratios can compensate for spatial resolution blurring. Importantly, it may be targeted imaging agents per se, again such as tilmanocept, which may significantly shrink any perceived chasm between the imaging technologies and anchor the diagnostic considerations in the targeting and specificity of the agent rather than any lingering dogma about the hardware as the basis for imaging approaches. Beyond the elements of imaging applications of these agents is their evolution to therapeutic agents as well, and even in the neo-logical realm of theranostics. Characteristics of agents such as tilmanocept that exploit the natural history of diseases with remarkably high specificity are the expectations for the future of patient- and disease-centered diagnosis and therapy.

Pediatric Melanoma and Atypical Melanocytic Neoplasms

Melanoma is uncommon in the pediatric age range, but is increasing in frequency and often presents with atypical features compared to the classic ABCDE criteria common to adult melanoma cases. Moreover, many melanocytic neoplasms in childhood pose diagnostic challenges to the pathologist, and sometimes cannot be unequivocally classified as benign nevi or melanoma. This chapter addresses the evaluation and management of pediatric patients with melanoma and atypical melanocytic neoplasms, including the roles of and unresolved questions surrounding sentinel lymph node biopsy, completion lymphadenectomy, adjuvant therapy, and treatment of advanced disease.

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.

A review of sentinel lymph node biopsy for thin melanoma

INTRODUCTION

Although there is a lack of established survival benefit of sentinel lymph node biopsy (SLNB), this technique has been increasingly applied in the staging of patients with thin (≤1.00 mm) melanoma (T1Nx), without clear supportive evidence.

METHODS

We review the guidelines and available literature on the indications and rationale for performing SLNB in thin melanoma.

RESULTS

As a consequence of the paucity of evidence of SLNB in thin melanoma, there is considerable variability in the guidelines. It is difficult to define clinicopathologic factors that reliably predict the presence of nodal metastasis. SLNB does not yet inform management in thin melanoma to improve survival outcome.

CONCLUSION

Based on available evidence, high risk patients with melanomas between 0.75 and 1.00 mm may be appropriate candidates to be considered for SLN biopsy after discussing the likelihood of finding evidence of nodal progression, the risks of sentinel node biopsy, and the lack of proven survival benefit from any form of surgical nodal staging.

The role of sentinel lymph node biopsy for thin cutaneous melanomas of the head and neck

From 18% to 35% of cutaneous melanomas are located in the head and neck, and nearly 70% are thin (Breslow thickness ≤ 1 mm). Sentinel lymph node biopsy (SLNB) has an established role in staging of intermediate-thickness melanomas, however its use in thin melanomas remains controversial. In this article, we review the literature regarding risk factors for occult nodal metastasis in thin cutaneous melanoma of the head and neck (CMHN). Based on the current literature, we recommend SLNB for all lesions with Breslow thickness ≥ 0.75 mm, particularly when accompanied by adverse features including mitotic rate ≥ 1 per mm(2), ulceration, and extensive regression. SLNB should also be strongly considered in younger patients (e.g. < 40 years old), especially in the presence of additional adverse features. All patients who do not proceed with sentinel lymph node biopsy must be carefully followed to monitor for regional relapse.

Sentinel lymph node biopsy in melanoma: controversies and current guidelines

ABSTRACT: 

Melanoma is a global health problem and the incidence of this disease is rising. While localized melanoma has an excellent prognosis, regional and distant disease is associated with much poorer outcomes. Optimal treatment for clinically localized melanoma requires surgical control of the primary site and accurate staging of the regional nodal basin with sentinel lymph node biopsy (SLNB). While further data are required to determine if SLNB is associated with a survival advantage, currently available data supports the use of SLNB for staging of appropriate patients and the procedure may offer benefits beyond staging. This article reviews current data that shapes guidelines regarding patient selection for SLNB in melanoma and highlights areas where performing this procedure remains controversial.

Impact of the 2009 (7th edition) AJCC melanoma staging system in the classification of thin cutaneous melanomas

CONTEXT

The 7th (2009) edition of the AJCC melanoma staging system incorporates tumor (Breslow) thickness, MR, and ulceration in stratifying T1 primary melanomas. Compared to the prior 6th (2001) edition, MR has replaced CL for thin melanomas.

OBJECTIVE

We sought to identify and report differences of the classification of thin melanomas as well as outcome of SLNB in patients according to the 6th and 7th editions at our institution.

RESULTS

106 patients were identified with thin melanomas verified by wide excision. 31 of 106 thin melanomas were reclassified according to the 7th edition of the AJCC. Of those 31, 15 CL II/III patients (6th edition T1a) were reclassified as T1b based on the presence of mitoses while 16 CL IV patients (6th edition T1b) were categorized as T1a based on the absence of mitoses. 26/31 reclassified patients underwent SLNB, and all were negative. Patients with thin melanoma and a +SLNB (N = 3) were all classified as T1b according to both staging systems.

CONCLUSIONS

In our experience, 29% of thin melanomas were reclassified according to the 7th edition with similar proportions of patients re-distributed as T1a (14%) and T1b (15%). Cases with +SLN corresponded with T1b lesions in both 6th and 7th editions.

Immunodetection of phosphohistone H3 as a surrogate of mitotic figure count and clinical outcome in cutaneous melanoma

In the American Joint Committee on Cancer (AJCC)-TNM (2009) staging system, the key prognostic factor in cutaneous melanoma is the depth of dermal invasion (Breslow thickness) with further refinement according to the presence of epidermal ulceration or dermal mitoses. Immunodetection of phosphohistone H3 has been shown to facilitate the identification of mitotic figures in various neoplasms. We selected 120 cases of primary cutaneous melanoma with completely annotated histopathologic parameters and clinical outcomes and performed double immunohistochemical staining for MLANA (Mart-1/Melan-A) and phosphohistone H3. One hundred and thirteen cases were amenable to antiphosphohistone H3 staining from 66 men and 47 women, with mean age of 64 years (9-93), including 61 superficial spreading type, 24 nodular, 6 lentigo maligna, 8 acral lentiginous, and 14 unclassified. The mean Breslow thickness was 2.53 mm (0.20-25), ulceration was present in 25/113 (22%) and the mean mitotic count was 3.2/mm(2) (<1-29/mm(2)). In 27/113 (24%) of the cases, antiphosphohistone H3 failed to highlight mitotic figures anywhere in the tissue (normal or tumor cell), whereas in 86/113 (76%) antiphosphohistone H3 detected at least one mitotic figure. Among the latter, antiphosphohistone H3 did not detect mitotic figures in dermal tumor cells in 37/86 cases (43%), whereas anti-PHH3 identified at least one melanocytic mitotic figure in the other 49/86 cases (57%; range: 1-66/mm(2)). The relationship between phosphohistone H3 and manual mitotic count was statistically significant (Pearson correlation=0.59, P<0.0001). Logistic regression analyses demonstrated an association between the development of subsequent metastatic disease and the following variables: mitotic figures (odds ratio (OR)=5.7; P=0.0001); phosphohistone H3-positive mitotic figures (OR=3.0; P=0.008); Breslow thickness (OR=4.0 per mm; P=0.0002); ulceration (OR=3.94; P=0.008). The application of phosphohistone H3 immunohistochemistry to the description of primary cutaneous melanoma is useful in identifying mitotic figures, improves upon the specificity of this designation when used together with MLANA, and correlates with an increased risk for metastasis in univariate analyses.

Completion lymph node dissection after a positive sentinel node: no longer a must?

PURPOSE OF REVIEW

Sentinel node biopsy (SNB) for primary melanoma is accepted worldwide as a diagnostic procedure. When sentinel node positive, the invasive completion lymph node dissection (CLND) is usually performed. Approximately 20% of CLND patients have nonsentinel node (NSN) metastases. The therapeutic benefit is unknown. This review analyzed the necessity of CLND in sentinel node positive patients.

RECENT FINDINGS

Prognosis of sentinel node positive patients is highly heterogeneous. The Rotterdam and Dewar criteria and S-classification are important sentinel node tumor burden criteria to stratify melanoma patients for prognosis and risk of NSN metastases. Patients with less than 0.1 mm metastases seem to have similar prognosis as sentinel node negative patients, especially when located in the subcapsular area. This depends on the use of an extensive sentinel node pathology protocol identifying possibly clinically irrelevant micrometastases.

SUMMARY

Consensus on the sentinel node pathology work-up and analysis protocols are crucial for correct risk stratification and for clinical decision-making. Primary and sentinel node tumor burden parameters and patient comorbidities should be taken into consideration when offering CLND to an individual patient. In the future, prospective studies such as the MSLT-II and the EORTC 1208 (Minitub) will provide answers to whether CLND has a therapeutic benefit and to which patients might safely be spared CLND.

Evidence-based clinical practice guidelines on the use of sentinel lymph node biopsy in melanoma

Sentinel lymph node biopsy (SLNB) was introduced in 1992 to allow histopathologic evaluation of the "sentinel" node, that is, the first node along the lymphatic drainage pathway from the primary melanoma. This procedure has less risk of complications than a complete lymphadenectomy, and if the sentinel node is uninvolved by tumor the likelihood a complete lymphadenectomy would find metastatic disease in that nodal basin is very low. SLNB is now widely used worldwide in the staging of melanoma as well as breast and Merkel cell carcinomas. SLNB provides safe, reliable staging for patients with clinically node-negative melanomas 1 mm or greater in thickness, with an acceptably low rate of failure in the sentinel node-negative basin. Evidence-based guidelines jointly produced by ASCO and the Society of Surgical Oncology (SSO) recommend SLNB for patients with intermediate-thickness melanomas and also state that SLNB may be recommended for patients with thick melanomas. Major remaining areas of uncertainty include the indications for SLNB in patients with thin melanomas, pediatric patients, and patients with atypical melanocytic neoplasms; the optimal radiotracers and dyes for lymphatic mapping; and the necessity of complete lymphadenectomy in all sentinel node-positive patients.