Distinct Clinicopathological and Prognostic Features of Thin Nodular Primary Melanomas: An International Study from 17 Centers

European consensus-based interdisciplinary guideline for melanoma. Part 1: Diagnostics - Update 2024

This guideline was developed in close collaboration with multidisciplinary experts from the European Association of Dermato-Oncology (EADO), the European Dermatology Forum (EDF) and the European Organization for Research and Treatment of Cancer (EORTC). Recommendations for the diagnosis and treatment of melanoma were developed on the basis of systematic literature research and consensus conferences. Cutaneous melanoma (CM) is the most dangerous form of skin tumor and accounts for 90 % of skin cancer mortality. The diagnosis of melanoma can be made clinically and must always be confirmed by dermoscopy. If melanoma is suspected, a histopathological examination is always required. Sequential digital dermoscopy and whole-body photography can be used in high-risk patients to improve the detection of early-stage melanoma. If available, confocal reflectance microscopy can also improve the clinical diagnosis in special cases. Melanoma is classified according to the 8th version of the American Joint Committee on Cancer classification. For thin melanomas up to a tumor thickness of 0.8 mm, no further diagnostic imaging is required. From stage IB, lymph node sonography is recommended, but no further imaging examinations. From stage IIB/C, whole-body examinations with computed tomography or positron emission tomography CT in combination with magnetic resonance imaging of the brain are recommended. From stage IIB/C and higher, a mutation test is recommended, especially for the BRAF V600 mutation. It is important to perform a structured follow-up to detect relapses and secondary primary melanomas as early as possible. A stage-based follow-up regimen is proposed, which in the experience of the guideline group covers the optimal requirements, although further studies may be considered. This guideline is valid until the end of 2026.

Diagnostic and prognostic risk factors analysis for distant metastasis in melanoma: a population-based study

BACKGROUND

We aimed to develop tools that could predict the occurrence of distant metastases in melanoma and its prognosis based on clinical and pathological characteristics.

MATERIALS AND METHODS

We obtained data from the Surveillance, Epidemiology, and End Results (SEER) database of melanoma patients diagnosed between 2010 and 2019. Logistic analyses were performed to identify independent risk factors associated with distant metastasis. Additionally, multivariate Cox analyses were conducted to determine independent prognostic factors for patients with distant metastasis. Two nomograms were established and evaluated with the receiver operating characteristic (ROC) curves, calibration curves, and decision curve analysis (DCA). Furthermore, we performed a retrospective analysis of melanoma with distant metastasis from our institute between March 2018 and June 2022.

RESULTS

Of the total 19 396 melanoma patients, 352 (1.8%) had distant metastases at the time of diagnosis. The following clinical and pathological characteristics were identified as independent risk factors for distant metastasis in melanoma: N stage, tumor size, ulceration, mitosis, primary tumor site, and pathological subtype. Furthermore, tumor size, pathological subtype, and radiotherapy were identified as independent prognostic factors. The results of the training and validation cohorts' ROC curves, calibration, DCA, and Kaplan-Meier survival curves demonstrate the effectiveness of the two nomograms. The retrospective study results from our center supported the results from the SEER database.

CONCLUSION

The clinical and pathological characteristics of melanoma can predict a patient's risk of metastasis and prognosis, and the two nomograms are expected to be effective tools to guide therapy decisions.

A Prognostic Model for Cancer-Specific Survival Among Patients with Nodular Melanoma in Head and Neck

OBJECTIVES

This study aims to evaluate the correlation between risk factors and treatment methods affecting nodular melanoma (NM) in the head and neck, as well as cancer-specific survival (CSS), and provide personalized predictive tools for clinical physicians.

METHODS

The retrospective study data of 1848 patients were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. All variables were included in the correlation analysis using the Spearman method. Significant prognostic factors were extracted and integrated through Cox risk regression analysis to construct a nomogram. To assess the performance of the nomogram, Harrell's concordance index (C-index) and a receiver operating characteristic (ROC) curve analysis were employed.

RESULTS

Spearman's correlation analysis revealed a positive correlation between radiotherapy and lymph node metastasis, whereas chemotherapy showed a stronger association with distant metastasis. However, Cox risk regression analysis demonstrated that Mohs surgery and wide excision with margins exceeding 1 cm yielded substantial therapeutic advantages. Five independent risk prognostic factors (Breslow thickness, ulceration, N classification, M classification, and surgery type) were employed to construct a nomogram. The C-index for this nomogram was 0.713 for the training set and 0.720 for the validation set. In the training set, the 3-, 5-, and 8-year areas under the curve (AUCs) for CSS were 0.752, 0.723, and 0.720, whereas the validation set's AUCs were 0.754, 0.763, and 0.760, respectively. Calibration curves indicated the nomogram's strong discriminative ability for predicting CSS.

CONCLUSION

In this study, we identified independent prognostic factors for patients with NM in head and neck and developed a relatively accurate model to predict the survival probability of them, which could contribute to the tumor assessment and clinical decision-making.

LEVEL OF EVIDENCE

3 Laryngoscope, 134:3611-3619, 2024.

Association of miR-146a-5p and miR-21-5p with Prognostic Features in Melanomas

BACKGROUND

Cutaneous melanoma (CM) is one of the most lethal tumors among skin cancers and its incidence is rising worldwide. Recent data support the role of microRNAs (miRNAs) in melanoma carcinogenesis and their potential use as disease biomarkers.

METHODS

We quantified the expression of miR-146a-5p and miR-21-5p in 170 formalin-fixed paraffin embedded (FFPE) samples of CM, namely 116 superficial spreading melanoma (SSM), 26 nodular melanoma (NM), and 28 lentigo maligna melanoma (LMM). We correlated miRNA expression with specific histopathologic features including Breslow thickness (BT), histological subtype, ulceration and regression status, and mitotic index.

RESULTS

miR-146a-5p and miR-21-5p were significantly higher in NM compared to SSM and LMM. The positive correlation between miR-146a-5p and miR-21-5p expression and BT was confirmed for both miRNAs in SSM. Considering the ulceration status, we assessed that individual miR-21-5p expression was significantly higher in ulcerated CMs. The increased combined expression of the two miRNAs was strongly associated with ulceration (p = 0.0093) and higher mitotic rate (≥1/mm2) (p = 0.0005). We demonstrated that the combination of two-miRNA expression and prognostic features (BT and ulceration) can better differentiate cutaneous melanoma prognostic groups, considering overall survival and time-to-relapse clinical outcomes. Specifically, miRNA expression can further stratify prognostic groups among patients with BT ≥ 0.8 mm but without ulceration. Our findings provide further insights into the characterization of CM with specific prognostic features. The graphical abstract was created with BioRender.com.

A Retrospective Study of Diameter and Breslow Thickness in Invasive Melanomas

INTRODUCTION

A diameter larger than 6 mm is included in the criteria used in public health messages to detect a cutaneous melanoma. We aimed to investigate the independent association of Breslow thickness with the melanoma diameter.

METHODS

A retrospective study was performed in patients with invasive melanomas of the nodular melanoma (NM) or superficial spreading melanoma (SSM) subtype. The quartiles of the diameter (lower, median, upper) were studied in non-parametric quantile regression model.

RESULTS

In total, 537 cases of invasive melanomas were included and 60% had Breslow thickness ≤1.0 mm. There were 429 SSM (79.9%) and 108 NM (20.1%). Although NMs were significantly thicker (median Breslow thickness: 2.7 mm vs. 0.7 mm, respectively, p < 0.0001), they were not associated with larger diameter compared to SSMs (p = 0.71). After adjustment for age and sex, melanoma location and subtype, having Breslow thickness ≤1.0 mm was not significantly associated with the lower quartile, median and upper quartile of the diameter (p values: 0.063, 0.083, and 0.791, respectively).

CONCLUSION

In our study including melanomas of the NM or SSM subtype, Breslow thickness was not associated with the diameter, adding evidence to support the limitations of using diameter larger than 6 mm for the detection of invasive melanomas and indicating the potential of smaller melanomas to be thicker tumors.

Sentinel lymph node biopsy status improves adjuvant therapy decision-making in patients with clinical stage IIB/C melanoma: A population-based analysis

BACKGROUND

Given the results of the recent KEYNOTE-716 trial, the performance of sentinel lymph node (SLN) biopsy for patients with clinical stage IIB/C melanoma has been questioned.

OBJECTIVE

Determine the utility of SLN status in guiding the recommendations for adjuvant therapy.

METHODS

Patients with clinical stage IIB/C cutaneous melanoma who underwent wide local excision and SLN biopsy between 2004 and 2011 were identified from the Surveillance, Epidemiology, and End Results database. Two prognostic models, with and without SLN status, were developed predicting risk of melanoma-specific death (MSD). The primary outcome was net benefit at treatment thresholds of 20% to 40% risk of 5-year MSD.

RESULTS

For the 4391 patients included, the 5-year MSD rate was 46%. The model estimating 5-year MSD risk that included SLN status provided greater net benefit at treatment thresholds from 30% to 78% compared to the model without SLN status. The added net benefit for the SLN biopsy-containing model persisted in subgroup analysis of patients in different age groups and with various T stages.

LIMITATIONS

Retrospective study.

CONCLUSIONS

A prognostic model with SLN status estimating patient risk for 5-year MSD provides superior net benefit compared to a model with primary tumor staging factors alone for threshold mortality rates ≥30%.

Systemic Therapy in Advanced Nodular Melanoma versus Superficial Spreading Melanoma: A Nation-Wide Study of the Dutch Melanoma Treatment Registry

Nodular melanoma (NM) is associated with a higher locoregional and distant recurrence rate compared with superficial spreading melanoma (SSM); it is unknown whether the efficacy of systemic therapy is limited. Here, we compare the efficacy of immunotherapy and BRAF/MEK inhibitors (BRAF/MEKi) in advanced NM to SSM. Patients with advanced stage IIIc and stage IV NM and SSM treated with anti-CTLA-4 and/or anti-PD-1, or BRAF/MEKi in the first line, were included from the prospective Dutch Melanoma Treatment Registry. The primary objectives were distant metastasis-free survival (DMFS) and overall survival (OS). In total, 1086 NM and 2246 SSM patients were included. DMFS was significantly shorter for advanced NM patients at 1.9 years (CI 95% 0.7−4.2) compared with SSM patients at 3.1 years (CI 95% 1.3−6.2) (p < 0.01). Multivariate survival analysis for immunotherapy and BRAF/MEKi demonstrated a hazard ratio for immunotherapy of 1.0 (CI 95% 0.85−1.17) and BRAF/MEKi of 0.95 (CI 95% 0.81−1.11). A shorter DMFS for NM patients developing advanced disease compared with SSM patients was observed, while no difference was observed in the efficacy of systemic immunotherapy or BRAF/MEKi between NM and SSM patients. Our results suggests that the worse overall survival of NM is mainly driven by propensity of metastatic outgrowth of NM after primary diagnosis.

Major Histotypes in Skin Melanoma: Nodular and Acral Lentiginous Melanomas Are Poor Prognostic Factors for Relapse and Survival

ABSTRACT

The histological subtype is not considered one of the major prognostic factors in melanoma, yet it is known to have an impact on survival. The aim of this study was to investigate the clinical significance of histological subtypes and the possible impacts of clinicopathological factors on the course of melanoma patients of all stages. A total of 1017 cutaneous melanoma patients were analyzed retrospectively. Four major melanoma histotypes that were studied in this study were as follows: (1) superficial spreading melanoma (SSM), (2) nodular melanoma (NM), (3) acral lentiginous melanoma (ALM), and (4) lentigo maligna melanoma (LMM). Unlike SSMs and LMMs, there were statistically significant correlations between NMs and ALMs and most aggressive histopathological prognostic indicators, such as higher Clark level ( P = 0.0001), thick Breslow depth ( P = 0.0001), presence of ulceration ( P = 0.0001), and lymphovascular invasion ( P = 0.0001). Furthermore, NMs and ALMs were also associated with advanced clinical stages, that is, node involvement and metastasis. Relapse rates for nonmetastatic melanomas were higher in NMs (39.6%) and ALMs (35.3%) than in SSMs (24.3%) and LMMs (10.3%) ( P = 0.0001). Additionally, 5-year relapse-free survival rates were 90.5%, 70.5%, 55.7%, and 50.5% in LMMs, SSMs, ALMs, and NMs, respectively ( P = 0.0001). Moreover, 5-year overall survival rates plummeted from 84.3% in LMMs to 74.8%, 64.3%, and 46% in SSMs, ALMs, and NMs, respectively ( P = 0.0001). In conclusion, we observed that the histologic subtype was an independent predictor for relapse and outcome for cutaneous melanoma patients. Both NM and ALM had unfavorable prognoses, and they were associated with known poor pathological and clinical indicators.

Metastatic multifocal melanoma of multiple organ systems: A case report

BACKGROUND

Malignant melanoma is becoming more common among middle-aged individuals all over the world. Melanoma metastasis can be found in various organs, although metastases to the spleen and stomach are rare. Herein we present a rare metastatic multifocal melanoma, clinically and histologically mimicking lymphoma, with metastases of multiple organs.

CASE SUMMARY

A 46-year-old Caucasian male with a history of nodular cutaneous malignant melanoma was presented with nausea, general weakness, shortness of breath, abdominal enlargement, and night sweating. The abdominal ultrasound revealed enlarged liver and spleen with multiple lesions. Computed tomography demonstrated multiple lesions in the lungs, liver, spleen, subcutaneous tissue, bones and a pathological lymphadenopathy of the neck. Trephine biopsy and the biopsy from the enlarged lymph node were taken. Tumor cells showed diffuse or partial positivity for melanocytic markers, such as microphthalmia - associated transcription factor, S100, HMB45 and Melan-A. The tumor harbored BRAF V600E mutation, demonstrated by immunohistochemical labelling for BRAF V600E and detected by real-time polymerase chain reaction test. Having combined all the findings, a diagnosis was made of a metastatic multifocal melanoma of the stomach, duodenum, liver, spleen, lungs, lymph nodes and bones. The patient refused treatment and died a week later.

CONCLUSION

This case report highlights the clinical relevance of rare metastatic multifocal melanoma of multiple organ systems.

European consensus-based interdisciplinary guideline for melanoma. Part 1: Diagnostics: Update 2022

Cutaneous melanoma (CM) is potentially the most dangerous form of skin tumor and causes 90% of skin cancer mortality. A unique collaboration of multi-disciplinary experts from the European Dermatology Forum (EDF), the European Association of Dermato-Oncology (EADO) and the European Organization for Research and Treatment of Cancer (EORTC) was formed to make recommendations on CM diagnosis and treatment, based on systematic literature reviews and the experts' experience. The diagnosis of melanoma can be made clinically and shall always be confirmed with dermatoscopy. If a melanoma is suspected, a histopathological examination is always required. Sequential digital dermatoscopy and full body photography can be used in high-risk patients to improve the detection of early melanoma. Where available, confocal reflectance microscopy can also improve clinical diagnosis in special cases. Melanoma shall be classified according to the 8th version of the American Joint Committee on Cancer classification. Thin melanomas up to 0.8 mm tumor thickness do not require further imaging diagnostics. From stage IB onwards, examinations with lymph node sonography are recommended, but no further imaging examinations. From stage IIC onwards whole-body examinations with computed tomography (CT) or positron emission tomography CT (PET-CT) in combination with brain magnetic resonance imaging are recommended. From stage III and higher, mutation testing is recommended, particularly for BRAF V600 mutation. It is important to provide a structured follow-up to detect relapses and secondary primary melanomas as early as possible. There is no evidence to define the frequency and extent of examinations. A stage-based follow-up scheme is proposed which, according to the experience of the guideline group, covers the optimal requirements, but further studies may be considered. This guideline is valid until the end of 2024.

Acral lentiginous melanoma histotype predicts outcome in clinical stage I-II melanoma patients: an International multicenter study

BACKGROUND

In the American Joint Committee on Cancer (AJCC) classification, acral lentiginous melanoma (ALM) histotype ALM is not included as an independent prognostic factor; in small series its negative prognostic impact on disease-free survival (DFS) and overall survival (OS) has been linked to the greater Breslow thickness (BT).

PATIENTS AND METHODS

The study was carried out at four referral melanoma centers (three Italian and one Polish). Clinical consecutive patients with stage I-II melanoma, who were diagnosed, treated, and followed up between January 1998 and March 2018 in annotated specific databases were included.

RESULTS

Overall, 6734 were evaluable, 4349 with superficial spreading melanoma (SSM), 2132 with nodular melanoma (NM), and 253 with ALM. At univariable analysis, a statistically significant worse DFS [hazard ratio (HR) 2.72, 95% confidence interval (CI) 2.24-3.30; P < 0.001] and OS (HR 2.67, 95% CI 2.15-3.32; P < 0.001) were found in patients with ALM compared with SSM. Similarly, the NM histotype was associated with a worse prognosis compared with the SSM histotype (DFS: HR 2.29, 95% CI 2.08-2.52; P < 0.001 and OS: HR 2.21, 95% CI 1.99-2.46; P < 0.001). At multivariable analysis, after adjusting for age, sex, BT, ulceration, and the sentinel lymph node status, a statistically significant worse DFS [adjusted HR (aHR; ALM versus SSM) 1.25, 95% CI 1.02-1.52; P = 0.028] was confirmed for patients with ALM. For patients with NM, instead, no impact of histology was found in terms of DFS [aHR (NM versus SSM) 1.04, 95% CI 0.93-1.15; P = 0.513] and OS [aHR (NM versus SSM) 0.96, 95% CI 0.86-1.08; P = 0.548].

CONCLUSIONS

ALM is associated with a worse long-term DFS. Our results could have important clinical implications for patients' stratification in future clinical trials and the incorporation of ALM histotype in the new AJCC classification as an independent prognostic factor.

Loss of 'Epidermal Melanin Unit' Integrity in Human Skin During Melanoma-Genesis

Cutaneous melanoma can be a most challenging neoplasm of high lethality, in part due to its extreme heterogeneity and characteristic aggressive and invasive nature. Indeed, its moniker 'the great masquerader' reflects that not all melanomas are created equal in terms of their originating cellular contexts, but also that melanoma cells in the malignant tumor can adopt a wide range of different cell states and variable organotropism. In this review, we focus on the early phases of melanomagenesis by discussing how the originating pigment cell of the melanocyte lineage can be influenced to embark on a wide range of tumor fates with distinctive microanatomical pathways. In particular, we assess how cells of the melanocyte lineage can differ by maturation status (stem cell; melanoblast; transiently amplifying cell; differentiated; post-mitotic; terminally-differentiated) as well as by micro-environmental niche (in the stratum basale of the epidermis; within skin appendages like hair follicle, eccrine gland, etc). We discuss how the above variable contexts may influence the susceptibility of the epidermal-melanin unit (EMU) to become unstable, which may presage cutaneous melanoma development. We also assess how unique features of follicular-melanin unit(s) (FMUs) can, by contrast, protect melanocytes from melanomagenesis. Lastly, we postulate how variable melanocyte fates in vitiligo, albinism, psoriasis, and alopecia areata may provide new insights into immune-/non immune-mediated outcomes for melanocytes in cutaneous melanin units.

Different mitotic rates are associated with different prognostic factors, relapses, and survival rates in melanoma

BACKGROUND

Mitotic rate is one of the major prognostic factors in melanoma.

OBJECTIVE

To investigate the significance of mitotic rate and possible impacts of clinicopathological factors on the course of all staged melanoma patients.

METHODS

A total number of 970 melanoma patients were analyzed. Mitotic rates were grouped for analysis as follows: 0-1, 1.1-4.9, 5-9.9, and ≥10 mitoses/mm² .

RESULTS

Melanomas with higher mitotic rates were more likely to be associated with nodular histology (P = 0.0001), higher Clark level (P = 0.0001), thick Breslow depth (P = 0.0001), ulceration (P = 0.0001), vertical growth pattern (P = 0.0001), neurotropism (P = 0.04), lymphovascular invasion (P = 0.01), de novo melanoma (P = 0.0001), absence of tumor infiltrating lymphocytes (P = 0.02), advanced stage (P = 0.0001), and relapse (P = 0.0001). The 5-year overall survival (OS) rate of all patients was 68.7%, and it decreased significantly from 87% in melanomas with 0-1 mitoses/mm² to 65.2%, 56.6%, and 50.4% in melanomas with 1.1-4.9, 5-9.9, and ≥10 mitoses/mm² , respectively (P = 0.0001). Age (P = 0.04), gender (P = 0.03), histology (P = 0.0001), Clark level (P = 0.001), T-stage (P = 0.003), ulceration (0.006), node involvement (P = 0.0001), metastasis (P = 0.005), and relapse (P = 0.0001) were correlated with OS in 0-1 mitoses/mm² melanomas, whereas lymphovascular invasion (P = 0.0001), BRAF mutation (P = 0.01), metastasis (P = 0.0001), relapse (P = 0.0001), and relapse pattern (P = 0.005) were found significant for ≥10 mitoses/mm² melanomas.

CONCLUSION

Higher tumor mitotic rates associated with known histopathological and clinical poor prognostic factors were found to be significantly independent predictors of early relapse and unfavorable survival for cutaneous melanoma patients. Moreover, different prognostic variables were found to be affecting survivals in melanoma patients with lower and higher mitosis.

Association of Histologic Regression With a Favorable Outcome in Patients With Stage 1 and Stage 2 Cutaneous Melanoma

Importance

Although regression is commonly observed in cutaneous melanoma, it is uncertain whether it is associated with patient prognosis.

Objective

To determine whether histologically confirmed regression was associated with better or worse survival in patients with primary cutaneous melanoma.

Design, Setting, and Participants

This cohort study analyzed data from 2 large cohorts of adults (one in the Netherlands and the other in Australia) with histologically proven, stage 1 and 2 primary, invasive cutaneous melanoma with known regression status treated between 2000 and 2014, with median follow-up times of 4.5 and 11.1 years for the Dutch and Australian cohorts, respectively. For the Dutch patients, population-based data from PALGA, the Dutch Pathology Registry, were used, and follow-up data were retrieved from the Netherlands Cancer Registry. For the Australian patients, data from the database of a large, specialized melanoma treatment center were used.

Main Outcomes and Measures

Multivariable Cox proportional hazards analyses were performed per cohort to assess recurrence-free survival (RFS) and overall survival (OS), and subgroup analyses according to Breslow thickness category and melanoma subtype were performed.

Results

A total of 17 271 Dutch patients and 4980 Australian patients were included. In both cohorts, survival outcomes were better for patients with disease regression. For Dutch patients, the hazard ratio (HR) for those with disease regression was 0.55 (95% CI, 0.48-0.63; P < .001) for RFS and 0.87 (95% CI, 0.79-0.96; P = .004) for OS; for the Australian patients, the HR was 0.61 (95% CI, 0.52-0.72; P < .001) for RFS and 0.73 (95% CI, 0.64-0.84; P < .001) for OS. Subgroup analyses showed that the presence of regression improved RFS within thin and intermediate Breslow thickness melanomas in both cohorts. For patients with superficial spreading melanoma (SSM) subtype, regression improved RFS and OS in both cohorts. For Dutch patients with SSM, the HR for those with disease regression was 0.54 (95% CI, 0.46-0.63; P < .001) for RFS and 0.86 (95% CI, 0.76-0.96; P = .009) for OS; for the Australian patients with SSM, the HR was 0.67 (95% CI, 0.52-0.85; P = .001) for RFS and 0.72 (95% CI, 0.59-0.88; P = .001) for OS.

Conclusions and Relevance

In 2 large patient cohorts from 2 different continents, regression was a favorable prognostic factor for patients with stage 1 and 2 melanomas, especially in those with thin and intermediate thickness tumors and those with SSM subtype.

A multicentre study of naevus-associated melanoma vs. de novo melanoma, tumour thickness and body site differences

BACKGROUND

Whether melanoma in histological contiguity with a naevus [naevus-associated melanoma (NAM)] is distinctly different from melanoma arising de novo remains unclear.

OBJECTIVES

To determine whether the characteristics of de novo melanoma differ from NAM and are not due to naevus obliteration in thicker tumours.

METHODS

We conducted a multicentre retrospective study of de novo melanoma and NAM in seven referral centres in Europe, Australia and the USA between 2006 and 2015.

RESULTS

In a total of 9474 localized melanomas, de novo melanoma was associated with thicker tumours and body site differences compared with NAM. In the subset of T1 melanomas (n = 5307), similar body site differences were found in multivariate analysis by body site. When compared with NAM, de novo melanoma was more likely to affect older individuals (≥ 70 years) when located on the head/neck [odds ratio (OR) 4·65, 95% confidence interval (CI) 2·55-8·46], the trunk (OR 1·82, 95% CI 1·40-2·36) or the upper extremity (OR 1·69, 95% CI 1·14-2·50), was more likely to affect female patients when located on the lower extremities (OR 1·36, 95% CI 1·03-1·80), and was more likely to be of the nodular melanoma subtype (OR 2·23, 95% CI 1·14-4·35) when located on the trunk. De novo melanoma was less likely to have regression present compared with NAM.

CONCLUSIONS

Clinicopathological and body site differences between de novo melanoma and NAM support the divergent pathway model of development. These differences were also found in thin melanomas, suggesting that de novo melanomas are different from NAM and their differences are not due to the obliteration of naevus remnants in thicker tumours.

Not all melanomas are created equal: a review and call for more research into nodular melanoma

Among the histogenic subtypes of melanoma, nodular melanoma (NM) is the major contributor for thicker and fatal melanomas and it has been associated with melanoma-specific death in thin tumours, highlighting an important subgroup of 'aggressive thin' melanomas. This review provides a synthesis of the distinct characteristics of NM, with respect to epidemiology and risk factors, clinical presentation, histopathology, molecular and dermoscopic aspects, and screening practices. The real challenges are to find better biomarkers of aggressiveness and to know whether the control of such aggressive melanomas can be influenced by targeted interventions such as early detection, drug interventions and preventive strategies.

Patient-identified early clinical warning signs of nodular melanoma: a qualitative study

BACKGROUND

Nodular (NM) and superficial spreading melanoma (SSM) show different disease trajectories, with more rapid development in NM and fewer opportunities for early detection often resulting in worse outcomes. Our study described the patient-identified early signs of thin NM via comparisons to thin (≤ 2 mm) SSM and thick (> 2 mm) NM.

METHODS

We conducted semi-structured interviews with NM and SSM patients and analyzed the data using thematic analysis.

RESULTS

We enrolled 34 NM and 32 SSM patients. Melanoma early signs uniquely identified by patients with thin NM included white, blue or black coloration, "dot-like" size, fast changes in shape and color observed over 2 weeks, elevation and texture or "puffiness" over 6-12 months, and the sensation that the mole "did not feel right". Early signs reported by both thin NM and thin SSM patients included round or oblong shape, "jagged" border, pink/red, brown/reddish or dark coloration, "elevated like a pimple" or "tiny bump", fast color darkening, diameter growth, and border irregularity, and mole feeling "really itchy".

CONCLUSIONS

We found evidence that early signs of NM can be self-identified, which has important implications for the earlier detection of this most aggressive type of melanoma by both health professionals and patients.

Five-year survival in patients with nodular and superficial spreading melanomas in the US population

BACKGROUND

Although superficial spreading melanomas (SSM) are diagnosed as thinner lesions, nodular melanomas (NM) have a more rapid growth rate and are biologically more aggressive compared with other histologic subtypes.

OBJECTIVE

To determine the difference in 5-year relative survival in patients with NM and SSM at the same Breslow depth and TNM stage.

METHODS

A population-based cross-sectional analysis compared the 5-year relative survival of patients with NM and SSM using data from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER)∗Stat software (version 8.2.1-8.3.5). Chi-square tests compared the proportions, and Kaplan-Meier method with Z-score compared 5-year relative survival.

RESULTS

For patients receiving a diagnosis between 2004 and 2009, 5-year relative survival was lower in NM compared with SSM (53.7% vs 87.3%; Z score, -41.35; P < .001). Similarly, for patients receiving a diagnosis between 2010 and 2015, 5-year relative survival was lower in NM compared with SSM (61.5% vs 89.7%; Z score, -2.7078; P < .01). Subgroup analyses showed inferior survival in NM in T1b, and survival differences remained significant after excluding patients with nodal or distant metastases.

CONCLUSIONS

Five-year relative survival is worse in NM compared with SSM especially in T1b, T2a, and T2b melanomas. Melanoma subtype should be taken into consideration when making treatment recommendations.

Multivariate analysis of prognostic factors in patients with nodular melanoma

PURPOSE

Nodular melanoma (NM) is associated with worse disease outcome when compared to superficial spreading melanoma (SSM). We aimed to perform a single-center analysis of prognostic factors in patients with NM and compare the data with SSM patients.

METHODS

We studied 228 patients with NN and 396 patients with SSM. Patients with in situ melanomas or stage IV at diagnosis were not included in the study. Data were analyzed using the Mann-Whitney test, Chi-square test, Kaplan-Meier curves including the log-rank test, and logistic regression model.

RESULTS

When compared to patients with SSM, patients with NM had less likely lower Clark level, higher tumor thickness, less likely tumor regression, more often ulcerated tumors, and less likely a history of precursor lesions such as a nevus. Within a 5-year follow-up we observed significantly more disease relapses and deaths in NM patients than in SSM patients. On multivariate analysis, disease relapse in NM patients was independently predicted by tumor thickness and positive SLNB, whereas melanoma-specific death of NM patients was independently predicted by male sex and tumor thickness. Histologic regression also remained in the logistic regression model as a significant independent negative predictor of NM death.

CONCLUSIONS

We did not observe that NM subtype was per se a significant independent predictor for disease relapse or melanoma-specific death. Among the well-known prognostic factors such as tumor thickness and male sex, NM is also associated with other unfavorable factors such as absence of regression.

Subtyping Cutaneous Melanoma Matters

Background

Our aim was to investigate the role of melanoma subtype on survival and focus on the effects stratified by Breslow thickness and ulceration status.

Methods

Patients with cutaneous melanoma stage I, II, or III diagnosed between 2000 and 2014 were derived from the Dutch Nationwide Pathology Registry and overall survival data from the Netherlands Cancer Registry. Patients were followed until 2018. Using multivariable Cox proportional hazards models, hazard ratios were calculated for each melanoma subtype, per Breslow thickness category and ulceration status, and adjusted for age, sex, stage, and localization.

Results

A total of 48 361 patients were included: 79.3% had superficial spreading melanoma (SSM), 14.6% nodular melanoma (NM), 5.2% lentigo maligna melanoma, and 0.9% acral lentiginous melanoma (ALM). In the total patient group, using SSM as the reference category, adjusted hazard ratios were 1.06 (95% confidence interval [CI] = 1.01 to 1.12) for NM, 1.02 (95% CI = 0.93 to 1.13) for lentigo maligna melanoma, and 1.26 (95% = CI 1.06 to 1.50) for ALM. Among patients with 1.0 mm or less Breslow thickness and no ulceration, NM showed a twofold increased risk (hazard ratio = 1.96, 95% CI = 1.58 to 2.45) compared with SSM. Compared with 1.0 mm or less SSM without ulceration, the hazard ratio for 1.0 mm or less SSM with ulceration was 1.94 (95% CI = 1.55 to 2.44), and the hazard ratio for 1.0 mm or less NM with ulceration was 3.46 (95% CI = 2.17 to 5.50). NM patients with tumors greater than 1.0 mm did not show worse survival than SSM patients with tumors greater than 1.0 mm.

Conclusions

In this large nationwide study, ALM patients showed worse survival than SSM patients. Among patients with melanomas that were thin (1.0 mm or less), NM subtype patients also showed worse survival than SSM patients.

Peritumoral Immune Infiltrate as a Prognostic Biomarker in Thin Melanoma

Thin melanomas are tumors less than 1 mm thick according to Breslow classification. Their prognosis is in most cases excellent. However, a small subset of these tumors relapses. These clinical findings emphasize the need of novel prognostic biomarkers to identify this subset of tumors. Characterization of tumor immune microenvironment (TIME) is currently investigated as a prognostic and predictive biomarker for cancer immunotherapy in several solid tumors including melanoma. Here, taking into account the limited availability of tumor tissues, by characterizing some of the characteristics of TIME such as number of infiltrating lymphocytes, HLA class I antigen and PD-L1 expression, we show that number of infiltrating CD8+ and FOXP3+ T cells as well as CD8+/FOXP3+ T cell ratio can represent a useful prognostic biomarker in thin melanoma. Although further investigations in a larger patient cohort are needed, these findings have potential clinical significance since they can be used to define subgroups of thin melanoma patients who have a worse prognosis and might need different treatment modalities.

Dermatoscopic features of thin (≤2 mm Breslow thickness) vs. thick (>2 mm Breslow thickness) nodular melanoma and predictors of nodular melanoma versus nodular non-melanoma tumours: a multicentric collaborative study by the International Dermoscopy Society

BACKGROUND

Thin nodular melanoma (NM) often lacks conspicuous melanoma-specific dermatoscopic criteria and escapes clinical detection until it progresses to a thicker and more advanced tumour.

OBJECTIVE

To investigate the dermatoscopic morphology of thin (≤2 mm Breslow thickness) vs. thick (>2 mm) NM and to identify dermatoscopic predictors of its differential diagnosis from other nodular tumours.

METHODS

Retrospective, morphological case-control study, conducted on behalf of the International Dermoscopy Society. Dermatoscopic images of NM and other nodular tumours from 19 skin cancer centres worldwide were collected and analysed.

RESULTS

Overall, 254 tumours were collected (69 NM of Breslow thickness ≤2 mm, 96 NM >2 mm and 89 non-melanoma nodular lesions). Light brown coloration (50.7%) and irregular brown dots/globules (42.0%) were most frequently observed in ≤2 mm NMs. Multivariate analysis revealed that dotted vessels (3.4-fold), white shiny streaks (2.9-fold) and irregular blue structureless area (2.4-fold) were predictors for thinner NM compared to non-melanoma nodular tumours. Overall, irregular blue structureless area (3.4-fold), dotted vessels (4.6-fold) and serpentine vessels (1.9-fold) were predictors of all NM compared to non-melanoma nodular lesions.

LIMITATIONS

Absence of a centralized, consensus pathology review and cases selected form tertiary centres maybe not reflecting the broader community.

CONCLUSIONS

Our study sheds light into the dermatoscopic morphology of thin NM in comparison to thicker NM and could provide useful clues for its differential diagnosis from other non-melanoma nodular tumours.

The 2018 World Health Organization Classification of Cutaneous, Mucosal, and Uveal Melanoma: Detailed Analysis of 9 Distinct Subtypes Defined by Their Evolutionary Pathway

CONTEXT.—

There have been major advances in the understanding of melanoma since the last revision of the World Health Organization (WHO) classification in 2006.

OBJECTIVE.—

To discuss development of the 9 distinct types of melanoma and distinguishing them by their epidemiology, clinical and histologic morphology, and genomic characteristics. Each melanoma subtype is placed at the end of an evolutionary pathway that is rooted in its respective precursor, wherever appropriate and feasible, based on currently known data. Each precursor has a variable risk of progression culminating in its fully evolved, invasive melanoma.

DATA SOURCES.—

This review is based on the "Melanocytic Tumours" section of the 4th edition of the WHO Classification of Skin Tumours, published in 2018.

CONCLUSIONS.—

Melanomas were divided into those etiologically related to sun exposure and those that are not, as determined by their mutational signatures, anatomic site, and epidemiology. Melanomas on the sun-exposed skin were further divided by the histopathologic degree of cumulative solar damage (CSD) of the surrounding skin, into low and high CSD, on the basis of degree of associated solar elastosis. Low-CSD melanomas include superficial spreading melanomas and high-CSD melanomas incorporate lentigo maligna and desmoplastic melanomas. The "nonsolar" category includes acral melanomas, some melanomas in congenital nevi, melanomas in blue nevi, Spitz melanomas, mucosal melanomas, and uveal melanomas. The general term melanocytoma is proposed to encompass "intermediate" tumors that have an increased (though still low) probability of disease progression to melanoma.

Phenotypic characterisation of immune cells associated with histological regression in cutaneous melanoma

Histological regression and tumour infiltrating lymphocytes represent an early sign of activation of the immune system against primary melanoma. The first phenomenon has been especially discussed in the literature because of its prognostic role, but no clear agreement on its evaluation has been reached. Immunotherapy of advanced stage melanoma has recently shown promising results; an improved understanding of the initial interplay between melanoma cells and the immune system would potentially help tailor treatment for patients. Seventy consecutive melanomas with regression were analysed to identify a prognostic cut-off value of regression extension. Then, we compared the immune infiltrate between regressed and not regressed areas of these regressed melanomas, assessing CD3, CD4, CD8, CD20, CD123, PD1 and FOXP3/CD25 expression. The immune infiltrate of these cases was further compared with 28 control melanomas without regression. A regression extension of 10% represented a reliable cut-off to distinguish two different risk categories in regressed melanomas. Regressed areas were less infiltrated by CD4/CD25, FOXP3/CD4 or PD1/CD4 compared to not regressed areas of each sample. These lymphocyte subsets are associated with anergy and hamper the immune CD8+ response towards the cancer cells. Moreover, the relevance of these findings was further supported by the observation that not regressed controls were significantly more infiltrated by these anergic immune cell subsets compared to the regressed cases. These results help understand the real meaning of regression in melanoma. Moreover, the association here identified between specific immunomodulatory immune cell subsets and regression could help in developing new therapeutic strategies.