Anatomic position determines oncogenic specificity in melanoma.

Oncogenic alterations to DNA are not transforming in all cellular contexts1,2. This may be due to pre-existing transcriptional programmes in the cell of origin. Here we define anatomic position as a major determinant of why cells respond to specific oncogenes. Cutaneous melanoma arises throughout the body, whereas the acral subtype arises on the palms of the hands, soles of the feet or under the nails3. We sequenced the DNA of cutaneous and acral melanomas from a large cohort of human patients and found a specific enrichment for BRAF mutations in cutaneous melanoma and enrichment for CRKL amplifications in acral melanoma. We modelled these changes in transgenic zebrafish models and found that CRKL-driven tumours formed predominantly in the fins of the fish. The fins are the evolutionary precursors to tetrapod limbs, indicating that melanocytes in these acral locations may be uniquely susceptible to CRKL. RNA profiling of these fin and limb melanocytes, when compared with body melanocytes, revealed a positional identity gene programme typified by posterior HOX13 genes. This positional gene programme synergized with CRKL to amplify insulin-like growth factor (IGF) signalling and drive tumours at acral sites. Abrogation of this CRKL-driven programme eliminated the anatomic specificity of acral melanoma. These data suggest that the anatomic position of the cell of origin endows it with a unique transcriptional state that makes it susceptible to only certain oncogenic insults.

Loss of 5-hydroxymethylcytosine is an epigenetic hallmark of melanoma.

DNA methylation at the 5 position of cytosine (5-mC) is a key epigenetic mark that is critical for various biological and pathological processes. 5-mC can be converted to 5-hydroxymethylcytosine (5-hmC) by the ten-eleven translocation (TET) family of DNA hydroxylases. Here, we report that "loss of 5-hmC" is an epigenetic hallmark of melanoma, with diagnostic and prognostic implications. Genome-wide mapping of 5-hmC reveals loss of the 5-hmC landscape in the melanoma epigenome. We show that downregulation of isocitrate dehydrogenase 2 (IDH2) and TET family enzymes is likely one of the mechanisms underlying 5-hmC loss in melanoma. Rebuilding the 5-hmC landscape in melanoma cells by reintroducing active TET2 or IDH2 suppresses melanoma growth and increases tumor-free survival in animal models. Thus, our study reveals a critical function of 5-hmC in melanoma development and directly links the IDH and TET activity-dependent epigenetic pathway to 5-hmC-mediated suppression of melanoma progression, suggesting a new strategy for epigenetic cancer therapy.

Development and validation of a novel model to predict recurrence-free survival and melanoma-specific survival after sentinel lymph node biopsy in patients with melanoma: an international, retrospective, multicentre analysis.

BACKGROUND: The introduction of adjuvant systemic treatment for patients with high-risk melanomas necessitates accurate staging of disease. However, inconsistencies in outcomes exist between disease stages as defined by the American Joint Committee on Cancer (8th edition). We aimed to develop a tool to predict patient-specific outcomes in people with melanoma rather than grouping patients according to disease stage. METHODS: Patients older than 13 years with confirmed primary melanoma who underwent sentinel lymph node biopsy (SLNB) between Oct 29, 1997, and Nov 11, 2013, at four European melanoma centres (based in Berlin, Germany; Amsterdam and Rotterdam, the Netherlands; and Warsaw, Poland) were included in the development cohort. Potential predictors of recurrence-free and melanoma-specific survival assessed were sex, age, presence of ulceration, primary tumour location, histological subtype, Breslow thickness, sentinel node status, number of sentinel nodes removed, maximum diameter of the largest sentinel node metastasis, and Dewar classification. A prognostic model and nomogram were developed to predict 5-year recurrence-free survival on a continuous scale in patients with stage pT1b or higher melanomas. This model was also calibrated to predict melanoma-specific survival. Model performance was assessed by discrimination (area under the time-dependent receiver operating characteristics curve [AUC]) and calibration. External validation was done in a cohort of patients with primary melanomas who underwent SLNB between Jan 30, 1997, and Dec 12, 2013, at the Melanoma Institute Australia (Sydney, NSW, Australia). FINDINGS: The development cohort consisted of 4071 patients, of whom 2075 (51%) were female and 1996 (49%) were male. 889 (22%) had sentinel node-positive disease and 3182 (78%) had sentinel node-negative disease. The validation cohort comprised 4822 patients, of whom 1965 (41%) were female and 2857 (59%) were male. 891 (18%) had sentinel node-positive disease and 3931 (82%) had sentinel node-negative disease. Median follow-up was 4·8 years (IQR 2·3-7·8) in the development cohort and 5·0 years (2·2-8·9) in the validation cohort. In the development cohort, 5-year recurrence-free survival was 73·5% (95% CI 72·0-75·1) and 5-year melanoma-specific survival was 86·5% (85·3-87·8). In the validation cohort, the corresponding estimates were 66·1% (64·6-67·7) and 83·3% (82·0-84·6), respectively. The final model contained six prognostic factors: sentinel node status, Breslow thickness, presence of ulceration, age at SLNB, primary tumour location, and maximum diameter of the largest sentinel node metastasis. In the development cohort, for the model's prediction of recurrence-free survival, the AUC was 0·80 (95% CI 0·78-0·81); for prediction of melanoma-specific survival, the AUC was 0·81 (0·79-0·84). External validation showed good calibration for both outcomes, with AUCs of 0·73 (0·71-0·75) and 0·76 (0·74-0·78), respectively. INTERPRETATION: Our prediction model and nomogram accurately predicted patient-specific risk probabilities for 5-year recurrence-free and melanoma-specific survival. These tools could have important implications for clinical decision making when considering adjuvant treatments in patients with high-risk melanomas. FUNDING: Erasmus Medical Centre Cancer Institute.

The Effect of Neoadjuvant Systemic Therapy on Surgical Outcomes After Lymph Node Dissections for Stage III Melanoma; An Australian Cohort.

BACKGROUND: Neoadjuvant systemic therapy (NAST) for patients with stage III melanoma achieves high major pathologic response rates and high recurrence-free survival rates. This study aimed to determine how NAST with targeted therapies (TTs) and immune checkpoint inhibitors (ICIs) influences surgical outcomes after lymph node dissection in terms of complications, morbidity, and textbook outcomes. METHODS: Patients who underwent a lymph node dissection after either NAST in a clinical trial or upfront surgery for stage III melanoma between 2014 and 2022 were identified from an institutional research database. RESULTS: The study included 89 NAST-treated patients and 79 upfront surgery-treated patients. The rate of postoperative complications did not differ between the NAST- and upfront surgery-treated patients (55% vs. 51%; p = 0.643), and steroid treatment for drug toxicity did not influence the complication rate (odds ratio [OR], 1.1; 95% confidence interval [CI], 0.4-3; p = 0.826). No significant differences in postoperative morbidity were observed in terms of seroma (23% vs. 11%; p = 0.570) or lymphedema (36% vs. 51%; p = 0.550). The rate of achieving a textbook outcome was comparable for the two groups (61% vs. 57%; p = 0.641). CONCLUSIONS: The surgical outcomes after lymph node dissections were comparable between the patients who received NAST and those who had upfront surgery, indicating that surgery can be safely performed after NAST with TT or ICI for stage III melanoma.

Impact of an Online Risk Calculator for Sentinel Node Positivity on Management of Patients with T1 and T2 Melanomas.

BACKGROUND: Predicting which patients with American Joint Committee on Cancer (AJCC) T1-T2 melanomas will have a positive sentinel lymph node (SLN) is challenging. Melanoma Institute Australia (MIA) developed an internationally validated SLN metastatic risk calculator. This study evaluated the nomogram's impact on T1-T2 melanoma patient management at MIA. METHODS: SLN biopsy (SLNB) rates were compared for the pre- and post-nomogram periods of 1 July 2018-30 June 2019 and 1 August 2020-31 July 2021, respectively. RESULTS: Overall, 850 patients were identified (pre-nomogram, 383; post-nomogram, 467). SLNB was performed in 29.0% of patients in the pre-nomogram group and 34.5% in the post-nomogram group (p = 0.091). The overall positivity rate was 16.2% in the pre-nomogram group and 14.9% in the post-nomogram group (p = 0.223). SLNB was performed less frequently in T1a melanoma patients in the pre-nomogram group (1.1%, n = 2/177) than in the post-nomogram group (8.6%, n = 17/198) [p ≤ 0.001]. This increase was particularly for melanomas with a risk score ≥ 5%, with an SLN positivity rate of 11.8% in the post-nomogram group (p = 0.004) compared with zero. For T1b melanomas with a risk score of > 10%, the SLNB rate was 40.0% (8/20) pre-nomogram and 75.0% (12/16) post-nomogram (p = 0.049). CONCLUSIONS: In this specialized center, the SLN risk calculator appears to influence practice for melanomas previously considered low risk for metastasis, with increased use of SLNB for T1a and higher-risk T1b melanomas. Further evaluation is required across broader practice settings. Melanoma management guidelines could be updated to incorporate the availability of nomograms to better select patients for SLNB than previous criteria.

Role of Concurrent Ultrasound Surveillance of Sentinel Node-Positive Node Fields in Melanoma Patients Having Routine Cross-Sectional Imaging.

PURPOSE: In sentinel node-positive (SN+ve) melanoma patients, active surveillance with regular ultrasound examination of the node field has become standard, rather than completion lymph node dissection (CLND). A proportion of these patients now receive adjuvant systemic therapy and have routine cross-sectional imaging (computed tomography [CT] or positron emission tomography [PET]/CT). The role of concurrent ultrasound (US) surveillance in these patients is unclear. The purpose of our study was to describe the modality of detection of nodal recurrence in SN+ve node fields. METHODS: SN+ve melanoma patients who did not undergo CLND treated at a single institution from January 1, 2016 to December 31, 2020 were included. RESULTS: A total of 225 SN+ve patients with a median follow-up of 23 months were included. Of these, 119 (53%) received adjuvant systemic therapy. Eighty (36%) developed a recurrence at any site; 24 (11%) recurred first in the SN+ve field, of which 12 (5%) were confirmed node field recurrence only at 2 months follow-up. The nodal recurrences were first detected by ultrasound in seven (3%), CT in seven (3%), and PET/CT in seven (3%) patients. All nodal recurrences evident on US were also evident on PET/CT and vice versa. CONCLUSIONS: The high rate of recurrences outside the node field and the identification of all US-detected nodal recurrences on concurrent cross-sectional imaging modalities suggest that routine concurrent ultrasound surveillance of the node-positive field may be unnecessary for SN+ve melanoma patients having routine cross-sectional imaging.

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.

Germline variants are associated with increased primary melanoma tumor thickness at diagnosis.

Germline genetic variants have been identified, which predispose individuals and families to develop melanoma. Tumor thickness is the strongest predictor of outcome for clinically localized primary melanoma patients. We sought to determine whether there is a heritable genetic contribution to variation in tumor thickness. If confirmed, this will justify the search for specific genetic variants influencing tumor thickness. To address this, we estimated the proportion of variation in tumor thickness attributable to genome-wide genetic variation (variant-based heritability) using unrelated patients with measured primary cutaneous melanoma thickness. As a secondary analysis, we conducted a genome-wide association study (GWAS) of tumor thickness. The analyses utilized 10 604 individuals with primary cutaneous melanoma drawn from nine GWAS datasets from eight cohorts recruited from the general population, primary care and melanoma treatment centers. Following quality control and filtering to unrelated individuals with study phenotypes, 8125 patients were used in the primary analysis to test whether tumor thickness is heritable. An expanded set of 8505 individuals (47.6% female) were analyzed for the secondary GWAS meta-analysis. Analyses were adjusted for participant age, sex, cohort and ancestry. We found that 26.6% (SE 11.9%, P = 0.0128) of variation in tumor thickness is attributable to genome-wide genetic variation. While requiring replication, a chromosome 11 locus was associated (P < 5 × 10-8) with tumor thickness. Our work indicates that sufficiently large datasets will enable the discovery of genetic variants associated with greater tumor thickness, and this will lead to the identification of host biological processes influencing melanoma growth and invasion.

International Center-Level Variation in Utilization of Completion Lymph Node Dissection and Adjuvant Systemic Therapy for Sentinel Lymph Node-Positive Melanoma at Major Referral Centers.

OBJECTIVE: The aim of this study was to determine overall trends and center-level variation in utilization of completion lymph node dissection (CLND) and adjuvant systemic therapy for sentinel lymph node (SLN)-positive melanoma. SUMMARY BACKGROUND DATA: Based on recent clinical trials, management options for SLN-positive melanoma now include effective adjuvant systemic therapy and nodal observation instead of CLND. It is unknown how these findings have shaped practice or how these contemporaneous developments have influenced their respective utilization. METHODS: We performed an international cohort study at 21 melanoma referral centers in Australia, Europe, and the United States that treated adults with SLN-positive melanoma and negative distant staging from July 2017 to June 2019. We used generalized linear and multinomial logistic regression models with random intercepts for each center to assess center-level variation in CLND and adjuvant systemic treatment, adjusting for patient and disease-specific characteristics. RESULTS: Among 1109 patients, performance of CLND decreased from 28% to 8% and adjuvant systemic therapy use increased from 29 to 60%. For both CLND and adjuvant systemic treatment, the most influential factors were nodal tumor size, stage, and location of treating center. There was notable variation among treating centers in management of stage IIIA patients and use of CLND with adjuvant systemic therapy versus nodal observation alone for similar risk patients. CONCLUSIONS: There has been an overall decline in CLND and simultaneous adoption of adjuvant systemic therapy for patients with SLN-positive melanoma though wide variation in practice remains. Accounting for differences in patient mix, location of care contributed significantly to the observed variation.

Cross-platform comparison of immune signatures in immunotherapy-treated patients with advanced melanoma using a rank-based scoring approach.

BACKGROUND: Gene expression profiling is increasingly being utilised as a diagnostic, prognostic and predictive tool for managing cancer patients. Single-sample scoring approach has been developed to alleviate instability of signature scores due to variations from sample composition. However, it is a challenge to achieve comparable signature scores across different expressional platforms. METHODS: The pre-treatment biopsies from a total of 158 patients, who have received single-agent anti-PD-1 (n = 84) or anti-PD-1 + anti-CTLA-4 therapy (n = 74), were performed using NanoString PanCancer IO360 Panel. Multiple immune-related signature scores were measured from a single-sample rank-based scoring approach, singscore. We assessed the reproducibility and the performance in reporting immune profile of singscore based on NanoString assay in advance melanoma. To conduct cross-platform analyses, singscores between the immune profiles of NanoString assay and the previous orthogonal whole transcriptome sequencing (WTS) data were compared through linear regression and cross-platform prediction. RESULTS: singscore-derived signature scores reported significantly high scores in responders in multiple PD-1, MHC-1-, CD8 T-cell-, antigen presentation-, cytokine- and chemokine-related signatures. We found that singscore provided stable and reproducible signature scores among the repeats in different batches and cross-sample normalisations. The cross-platform comparisons confirmed that singscores derived via NanoString and WTS were comparable. When singscore of WTS generated by the overlapping genes to the NanoString gene set, the signatures generated highly correlated cross-platform scores (Spearman correlation interquartile range (IQR) [0.88, 0.92] and r2 IQR [0.77, 0.81]) and better prediction on cross-platform response (AUC = 86.3%). The model suggested that Tumour Inflammation Signature (TIS) and Personalised Immunotherapy Platform (PIP) PD-1 are informative signatures for predicting immunotherapy-response outcomes in advanced melanoma patients treated with anti-PD-1-based therapies. CONCLUSIONS: Overall, the outcome of this study confirms that singscore based on NanoString data is a feasible approach to produce reliable signature scores for determining patients' immune profiles and the potential clinical utility in biomarker implementation, as well as to conduct cross-platform comparisons, such as WTS.

Prognostic Significance and Management of Sentinel Nodes in the Triangular Intermuscular Space of Patients with Melanoma.

BACKGROUND: The clinical significance of sentinel nodes (SNs) in the triangular intermuscular space (TIS) of patients with melanoma is poorly understood. This study aimed to determine their incidence and positivity rate, and to report their management and patient outcomes. METHODS: This was a single-institution retrospective cohort study of patients with unilateral or bilateral TIS SNs on lymphoscintigraphy treated between 1992 and 2017. Recurrence-free survival was analyzed. RESULTS: Lymphoscintigraphy identified TIS SNs in 266 patients. They were bilateral in 17 patients. Of the 2296 patients with a melanoma on the upper back, 259 (11%) had TIS SNs. Procurement of SNs was not attempted in 122 (43%) of the 283 cases and failed in 11 cases (7%). An SN was successfully retrieved from the TIS in 145 patients (53%) and contained metastasis in 18 of 150 TIS SNs. This was the only positive SN in 12 patients (8%), upstaging all of them. Of the 18 patients with a positive SN in the TIS, 9 (50%) underwent completion axillary lymph node dissection, but no additional involved nodes were found in any of these patients. Recurrence in the TIS was observed in six patients (5%), none of whom had their TIS SN surgically pursued previously. CONCLUSIONS: Lymphoscintigraphy showed TIS SNs in 11% of patients with melanomas on their upper back. In such cases, retrieval of TIS SNs is required for accurate staging and to minimize the risk of TIS recurrence.

Adjuvant radiotherapy after salvage surgery for melanoma recurrence in a node field following a previous lymph node dissection.

BACKGROUND AND OBJECTIVES: Adjuvant radiotherapy (RT) can be given to melanoma patients following salvage surgery for node field recurrence after a previous regional node dissection, but the value of this treatment strategy is poorly documented. This study evaluated long-term node field control and survival of patients treated in this way in an era before effective adjuvant systemic therapy became available. METHODS: Data for 76 patients treated between 1990 and 2011 were extracted from an institutional database. Baseline patient characteristics, treatment details and oncological outcomes were analysed. RESULTS: Adjuvant RT with conventional fractionation (median dose 48 Gy in 20 fractions) was given to 43 patients (57%) and hypofractionated RT (median dose 33 Gy in 6 fractions) to 33 patients (43%). The 5-year node field control rate was 70%, 5-year recurrence-free survival 17%, 5-year melanoma-specific survival 26% and 5-year overall survival 25%. CONCLUSIONS: Salvage surgery with adjuvant RT achieved node field control in 70% of melanoma patients with node field recurrence following a prior node dissection. However, disease progression at distant sites was common and survival outcomes were poor. Prospective data will be required to assess outcomes for contemporary combinations of surgery, adjuvant RT and systemic therapy.

Melanomas in children and adolescents: Clinicopathologic features and survival outcomes.

BACKGROUND: Melanomas in the first 2 decades of life are uncommon and poorly understood. OBJECTIVE: To assess clinicopathologic features and survival of children (≤11 years) and adolescents (12-19 years) diagnosed with melanoma. METHODS: A pooled cohort of 514 patients was analyzed (397 Dutch, 117 Australian; 62 children, 452 adolescents). Pathology reports were reevaluated to determine melanoma subtypes. Multivariable Cox models were generated for recurrence-free survival (RFS) and overall survival (OS). RESULTS: Melanoma subtypes were conventional melanoma (superficial spreading, nodular, desmoplastic, and acral lentiginous), spitzoid melanoma, and melanoma associated with a congenital nevus in 428, 78, and 8 patients, respectively. Ten-year RFS was 91.5% (95% confidence interval [CI], 82.4%-100%) in children and 86.4% (95% CI, 82.7%-90.3%) in adolescents (P = .32). Ten-year OS was 100% in children and 92.7% (95% CI, 89.8%-95.8%) in adolescents (P = .09). On multivariable analysis possible only for the adolescent cohort due to the small number of children, ulceration status, and anatomic site were associated with RFS and OS, whereas age, sex, mitotic index, sentinel node status and melanoma subtype were not. Breslow thickness >4 mm was associated with worse RFS. LIMITATIONS: Retrospective study. CONCLUSIONS: Survival rates for children and adolescents with melanomas were high. Ulceration, head or neck location and Breslow thickness >4 mm predicted worse survival in adolescents.

Development and validation of risk calculators for people with "thin" melanomas on their skin to predict the likelihood that their cancer will return: a plain language summary of publication.

WHAT IS THIS SUMMARY ABOUT?: This is a summary of an article describing the development of risk calculators for use in people who develop a type of melanoma on their skin called "thin" melanoma to predict the likelihood that their cancer will return. The article was originally published in the Journal of Clinical Oncology in 2021. HOW WERE THE CALCULATORS DEVELOPED?: Calculations were performed to predict the chance of people with thin melanomas surviving without their melanoma recurring. Three graphical prediction calculators (called nomograms) were developed, along with easy-to-use online calculators using the same underlying calculation methods. The model was developed using data for 25,930 Dutch people diagnosed with thin melanomas (called the "development set"). To test its ability to predict melanoma recurrence, it was then compared with data for 2,968 Australian people with melanoma (the "validation set"). The calculators developed in the Dutch patients were found to accurately predict the risk of melanoma recurring for people with melanoma in the Australian "validation" group. WHAT DO THE RESULTS MEAN?: The calculators provide estimates of the risk of the melanoma returning for people with thin melanomas. The easy-to-use online calculators are freely available on a smartphone, tablet or computer, and will assist in providing accurate estimates of recurrence risks for individuals with thin melanomas, allowing more intensive follow-up of those whose predicted risk of their melanoma returning is high.

Whole-genome landscapes of major melanoma subtypes.

Melanoma of the skin is a common cancer only in Europeans, whereas it arises in internal body surfaces (mucosal sites) and on the hands and feet (acral sites) in people throughout the world. Here we report analysis of whole-genome sequences from cutaneous, acral and mucosal subtypes of melanoma. The heavily mutated landscape of coding and non-coding mutations in cutaneous melanoma resolved novel signatures of mutagenesis attributable to ultraviolet radiation. However, acral and mucosal melanomas were dominated by structural changes and mutation signatures of unknown aetiology, not previously identified in melanoma. The number of genes affected by recurrent mutations disrupting non-coding sequences was similar to that affected by recurrent mutations to coding sequences. Significantly mutated genes included BRAF, CDKN2A, NRAS and TP53 in cutaneous melanoma, BRAF, NRAS and NF1 in acral melanoma and SF3B1 in mucosal melanoma. Mutations affecting the TERT promoter were the most frequent of all; however, neither they nor ATRX mutations, which correlate with alternative telomere lengthening, were associated with greater telomere length. Most melanomas had potentially actionable mutations, most in components of the mitogen-activated protein kinase and phosphoinositol kinase pathways. The whole-genome mutation landscape of melanoma reveals diverse carcinogenic processes across its subtypes, some unrelated to sun exposure, and extends potential involvement of the non-coding genome in its pathogenesis.

Clinical management of melanocytic tumours of uncertain malignant potential (MelTUMPs), including melanocytomas: A systematic review and meta-analysis.

Little guidance is currently available for managing patients with melanocytic tumours of uncertain or low malignant potential (MelTUMPs, including melanocytomas), in particular the optimal excision margins and whether to offer sentinel node biopsy (SNB). The objective of this review was to evaluate excision margins and the prognostic utility of SNB by systematic review of the literature and meta-analysis. PRISMA guidelines were followed. Medline, EMBASE and Cochrane databases were searched to October 2021 for studies of patients with MelTUMPs reporting excision margins and/or SNB-positivity. Meta-analysis was performed on the SNB-positivity rate using a random effects model, followed by sensitivity analyses on subgroups. 111 primary studies reported excision margins and/or SNB data for 1962 patients. Follow-up was available for 1649 patients: 1561 (94.7%) were alive without disease at last review, 53 (3.2%) had developed further disease, 29 (1.8%) had died of metastatic disease (melanoma) and six (0.4%) died of unrelated causes. SNB was performed in 837 patients. The pooled positivity rate on meta-analysis was 32% (95% CI: 23-44%). Clinical outcome could be correlated with excision margin in only 171 patients (60% of those with known follow up) and was therefore not analysed further. Evidence indicating the ideal excision margins for MelTUMPs was lacking. SNB had a high positivity rate despite very low rates of recurrence or melanoma-related death. Consequently, SNB should not be offered routinely for MelTUMPs (including melanocytomas), due to its lack of prognostic utility for this tumour type (high certainty of evidence).

Multiplex melanoma families are enriched for polygenic risk.

Cancers, including cutaneous melanoma, can cluster in families. In addition to environmental etiological factors such as ultraviolet radiation, cutaneous melanoma has a strong genetic component. Genetic risks for cutaneous melanoma range from rare, high-penetrance mutations to common, low-penetrance variants. Known high-penetrance mutations account for only about half of all densely affected cutaneous melanoma families, and the causes of familial clustering in the remainder are unknown. We hypothesize that some clustering is due to the cumulative effect of a large number of variants of individually small effect. Common, low-penetrance genetic risk variants can be combined into polygenic risk scores. We used a polygenic risk score for cutaneous melanoma to compare families without known high-penetrance mutations with unrelated melanoma cases and melanoma-free controls. Family members had significantly higher mean polygenic load for cutaneous melanoma than unrelated cases or melanoma-free healthy controls (Bonferroni-corrected t-test P = 1.5 × 10-5 and 6.3 × 10-45, respectively). Whole genome sequencing of germline DNA from 51 members of 21 families with low polygenic risk for melanoma identified a CDKN2A p.G101W mutation in a single family but no other candidate high-penetrance melanoma susceptibility genes. This work provides further evidence that melanoma, like many other common complex disorders, can arise from the joint action of multiple predisposing factors, including rare high-penetrance mutations, as well as via a combination of large numbers of alleles of small effect.

Higher polygenic risk for melanoma is associated with improved survival in a high ultraviolet radiation setting.

BACKGROUND: The role of germline genetic factors in determining survival from cutaneous melanoma (CM) is not well understood. OBJECTIVE: To perform a genome-wide association study (GWAS) meta-analysis of melanoma-specific survival (MSS), and test whether a CM-susceptibility polygenic risk score (PRS) is associated with MSS. METHODS: We conducted two Cox proportional-hazard GWAS of MSS using data from the Melanoma Institute Australia, a high ultraviolet (UV) radiation setting (MIA; 5,762 patients with melanoma; 800 melanoma deaths) and UK Biobank (UKB: 5,220 patients with melanoma; 241 melanoma deaths), and combined them in a fixed-effects meta-analysis. Significant (P < 5 × 10-8) results were investigated in the Leeds Melanoma Cohort (LMC; 1,947 patients with melanoma; 370 melanoma deaths). We also developed a CM-susceptibility PRS using a large independent GWAS meta-analysis (23,913 cases, 342,870 controls). The PRS was tested for an association with MSS in the MIA and UKB cohorts. RESULTS: Two loci were significantly associated with MSS in the meta-analysis of MIA and UKB with lead SNPs rs41309643 (G allele frequency 1.6%, HR = 2.09, 95%CI = 1.61-2.71, P = 2.08 × 10-8) on chromosome 1, and rs75682113 (C allele frequency 1.8%, HR = 2.38, 95%CI = 1.77-3.21, P = 1.07 × 10-8) on chromosome 7. While neither SNP replicated in the LMC, rs75682113 was significantly associated in the combined discovery and replication sets. After adjusting for age at diagnosis, sex and the first ten principal components, a one standard deviation increase in the CM-susceptibility PRS was associated with improved MSS in the discovery meta-analysis (HR = 0.88, 95% CI = 0.83-0.94, P = 6.93 × 10-5; I2 = 88%). However, this was only driven by the high UV setting cohort (MIA HR = 0.84, 95% CI = 0.78-0.90). CONCLUSION: We found two loci potentially associated with MSS. Increased genetic susceptibility to develop CM is associated with improved MSS in a high UV setting.

Clinicopathological Characteristics Predicting Further Recurrence and Survival Following Resection of In-Transit Melanoma Metastases.

BACKGROUND: In-transit metastases (ITMs) affect approximately 4% of patients with cutaneous melanoma. This study sought to identify clinical and pathological characteristics that predict further recurrence and survival following resection of ITMs. PATIENTS AND METHODS: Patients (n = 573) who underwent surgical resection of their first presentation of ITM following previous surgical treatment of an American Joint Committee on Cancer (AJCC) stage I-II melanoma between 1969 and 2017 were identified from an institutional database. Clinicopathological predictors of patterns of recurrence and survival following ITM resection were sought. RESULTS: The median time of ITM development was 2.4 years after primary melanoma resection. ITMs were most frequently located on the lower limb (51.0%). The most common melanoma subtype associated with ITM development was nodular melanoma (44.1%). After surgical resection of a first ITM, 65.4% of patients experienced recurrent disease. Most recurrences were locoregional (44.7%), with distant metastasis occurring in 23.9% of patients. Lower limb ITMs were more frequently associated with subsequent ITMs [odds ratio (OR) 2.41, p = 0.0002], and the lowest risk of distant metastasis (p < 0.0001) compared with other primary sites. Primary melanomas and ITM on head and neck, as well as the presence of ulceration, were associated with worse survival. CONCLUSIONS: Recurrence after surgical resection of a first ITM was common. Patterns of recurrence differed according to anatomical site; further ITM recurrences were more likely for lower limb ITMs, which were also associated with longer distant recurrence-free survival. Distant metastasis was more common for ITM on the head and neck, with worse survival.

The Impact of Surveillance Imaging Frequency on the Detection of Distant Disease for Patients with Resected Stage III Melanoma.

BACKGROUND: It is not known whether there is a survival benefit associated with more frequent surveillance imaging in patients with resected American Joint Committee on Cancer stage III melanoma. OBJECTIVE: The aim of this study was to investigate distant disease-free survival (DDFS), melanoma-specific survival (MSS), post distant recurrence MSS (dMSS), and overall survival for patients with resected stage III melanoma undergoing regular computed tomography (CT) or positron emission tomography (PET)/CT surveillance imaging at different intervals. PATIENTS AND METHODS: A closely followed longitudinal cohort of patients with resected stage IIIA-D disease treated at a tertiary referral center underwent 3- to 4-monthly, 6-monthly, or 12-monthly surveillance imaging between 2000 and 2017. Survival outcomes were estimated using the Kaplan-Meier method, and log-rank tests assessed the significance of survival differences between imaging frequency groups. RESULTS: Of 473 patients (IIIA, 19%; IIIB, 31%; IIIC, 49%; IIID, 1%) 30% underwent 3- to 4-monthly imaging, 10% underwent 6-monthly imaging, and 60% underwent 12-monthly imaging. After a median follow-up of 6.2 years, distant recurrence was recorded in 252 patients (53%), with 40% detected by surveillance CT or PET/CT, 43% detected clinically, and 17% with another imaging modality. Median DDFS was 5.1 years (95% confidence interval 3.9-6.6). Among 139 IIIC patients who developed distant disease, the median dMSS was 4.4 months shorter in those who underwent 3- to 4-monthly imaging than those who underwent 12-monthly imaging. CONCLUSION: Selecting patients at higher risk of distant recurrence for more frequent surveillance imaging yields a higher proportion of imaging-detected distant recurrences but is not associated with improved survival. A randomized comparison of low versus high frequency imaging is needed.