Epidemiology and survival of Merkel cell carcinoma in New Zealand: A population-based study between 2000 and 2015 with international comparison

Dermoscopic characteristics of Merkel cell carcinoma

BACKGROUND

Merkel cell carcinoma (MCC) is a rare, aggressive, cutaneous tumour with high mortality and frequently delayed diagnosis. Clinically, it often manifests as a rapidly growing erythematous to purple nodule usually located on the lower extremities or face and scalp of elderly patients. There is limited available data on the dermoscopic findings of MCC, and there are no specific features that can be used to definitively diagnose MCC.

AIM OF THE STUDY

Here, we aimed to summarize existing published literature on dermatoscopic and reflectance confocal microscopy (RCM) features of MCC.

MATERIALS AND METHODS

To find relevant studies, we searched the PubMed and Scopus databases from inception to April 12, 2023. Our goal was to identify all pertinent research that had been written in English. The following search strategy was employed: (" dermoscopy" OR " dermatoscopy" OR " videodermoscopy" OR " videodermatoscopy" OR " reflectance confocal microscopy") AND " Merkel cell carcinoma". Two dermatologists, DK and GE, evaluated the titles and abstracts separately for eligibility. For inclusion, only works written in English were taken into account.

RESULTS

In total 16 articles were retrieved (68 cases). The main dermoscopic findings of MCC are a polymorphous vascular pattern including linear irregular, arborizing, glomerular, and dotted vessels on a milky red background, with shiny or non-shiny white areas. Pigmentation was lacking in all cases. The RCM images showed a thin and disarranged epidermis, and small hypo-reflective cells that resembled lymphocytes arranged in solid aggregates outlined by fibrous tissue in the dermis. Additionally, there were larger polymorphic hyper-reflective cells that likely represented highly proliferative cells.

CONCLUSION

Dermoscopic findings of MCC may play a valuable role in evaluating MCC, aiding in the early detection and differentiation from other skin lesions. Further prospective case-control studies are needed to validate these results.

Incidence and Relative Survival of Patients with Merkel Cell Carcinoma in North Rhine-Westphalia, Germany, 2008-2021

BACKGROUND

To date, only a few population-representative studies have been carried out on the rare Merkel cell carcinoma (MCC). We provide incidence and survival estimates of MCC, including the conditional relative survival.

METHODS

We analyzed data from the cancer registry of North Rhine-Westphalia, Germany, 2008-2021, covering a population of 18 million. We included all newly diagnosed MCCs and calculated age-standardized (old European Standard population) incidence rates and unconditional and conditional relative survival.

RESULTS

Our analysis included 2164 MCC patients. The age-standardized incidence of MCC was 5.2 (men) and 3.8 (women) per million person-years. The 5-year relative survival was 58.8% (men) and 70.7% (women). Survival was lower among men than women in all age-sex groups and was highest for MCC of the upper extremity in both men (68.2%) and women (79.3%). The sex difference in survival is particularly due to the better survival of women with MCC of the head and neck. In terms of survival, the first two years are particularly critical.

CONCLUSIONS

Our data validate the worse survival among men and highlights a more favorable prognosis for MCCs located on the limbs. The first two years after diagnosis of MCC are the years with the highest excess mortality.

Incidence, mortality and survival of Merkel cell carcinoma: a systematic review of population-based studies

BACKGROUND

Merkel cell carcinoma (MCC) is a rare, aggressive skin cancer that most commonly occurs in ultraviolet-exposed body sites. The epidemiology of MCC in different geographies and populations is not well characterized.

OBJECTIVES

The objective of this systematic review is to summarize evidence on the incidence, mortality and survival rates of MCC from population-based studies.

METHODS

We searched MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials from database inception to 6 June 2023. No geographic, age or date exclusions were applied. We included population-based studies of MCC that reported the incidence, survival or mortality rate, and also considered systematic reviews. A data-charting form was created and validated to identify variables to extract. Two reviewers then independently charted the data for each included study with patient characteristics, and estimates of incidence rate, mortality rate, and survival rate and assessed the quality of included studies using the Joanna Briggs Institute Checklist for Prevalence studies, Newcastle-Ottawa Scale and Assessment of Multiple Systematic Reviews. We abstracted age-, sex-, stage- and race-stratified outcomes, and synthesized comparisons between strata narratively and using vote counting. We assessed the certainty of evidence for those comparisons using the Grading of Recommendations, Assessments, Developments and Evaluations framework.

RESULTS

We identified 11 472 citations, of which 52 studies from 24 countries met our inclusion criteria. Stage I and the head and neck were the most frequently reported stage and location at diagnosis. The incidence of MCC is increasing over time (high certainty), with the highest reported incidences reported in southern hemisphere countries [Australia (2.5 per 100 000); New Zealand (0.96 per 100 000) (high certainty)]. Male patients generally had higher incidence rates compared with female patients (high certainty), although there were some variations over time periods. Survival rates varied, with lower survival and/or higher mortality associated with male sex (moderate certainty), higher stage at diagnosis (moderate-to-high certainty), older age (moderate certainty), and immunosuppression (low-to-moderate certainty).

CONCLUSIONS

MCC is increasing in incidence and may increase further given the ageing population of many countries. The prognosis of MCC is poor, particularly for male patients, those who are immunosuppressed, and patients diagnosed at higher stages or at an older age.

Moderne Diagnostik und Therapie des Merkelzellkarzinoms

Das Merkelzellkarzinom (MCC) ist ein seltener, aggressiver Hauttumor mit epithelialer und neuroendokriner Differenzierung, dessen Inzidenz in den letzten Jahrzehnten deutlich zugenommen hat. Risikofaktoren sind fortgeschrittenes Lebensalter, heller Hauttyp, UV‐Exposition und Immunsuppression. Pathogenetisch wird ein durch das Merkelzell‐Polyomavirus (MCPyV) hervorgerufener Typ von einem UV‐induzierten Typ mit hoher Tumormutationslast unterschieden.

Klinisch präsentiert sich das MCC als meist schmerzloser, schnell wachsender, rötlich‐violetter Tumor mit glänzender Oberfläche, der bevorzugt im Kopf‐Hals‐Bereich und an den distalen Extremitäten lokalisiert ist. Eine sichere Diagnose kann nur anhand histologischer und immunhistochemischer Merkmale gestellt werden. Bei Erstdiagnose weisen 20%–26% der Patienten lokoregionäre Metastasen und 8%–14% Fernmetastasen auf, weshalb eine Ausbreitungsdiagnostik unabdingbar ist. Bei fehlenden klinischen Hinweisen auf Metastasen wird eine Sentinel‐Lymphknotenbiopsie empfohlen.

Wesentliche Säulen der Therapie sind die Operation, die adjuvante oder palliative Strahlentherapie und in fortgeschrittenen inoperablen Stadien die medikamentöse Tumortherapie. Die Einführung von Immuncheckpoint‐Inhibitoren führte zu einem Paradigmenwechsel, da sich hiermit ein wesentlich langfristigeres Ansprechen und bessere Überlebensraten als mit Chemotherapie erreichen lassen. Zur Therapie des metastasierten MCC ist in Deutschland der PD‐L1‐Inhibitor Avelumab zugelassen, aber auch die PD‐1‐Antikörper Pembrolizumab und Nivolumab werden mit Erfolg eingesetzt. Adjuvante und neoadjuvante Therapiekonzepte, Immunkombinationstherapien und zielgerichtete Therapien als Monotherapie oder in Kombination mit Immuncheckpoint‐Inhibitoren befinden sich in klinischer Prüfung.

Modern diagnostics and treatment of Merkel cell carcinoma

Merkel cell carcinoma (MCC) is a rare, aggressive skin cancer with epithelial and neuroendocrine differentiation, the incidence of which has increased substantially during the last decades. Risk factors include advanced age, fair skin type, UV exposure, and immunosuppression. Pathogenetically, a type caused by the Merkel cell polyomavirus is distinguished from a UV-induced type with a high tumor mutational burden. Clinically, MCC presents as a mostly painless, rapidly growing, reddish-violet tumor with a shiny surface, which is preferentially localized in the head-neck region and at the distal extremities. A reliable diagnosis can only be made based on histological and immunohistochemical features. At initial diagnosis, 20-26% of patients show locoregional metastases and 8-14% distant metastases, making staging examinations indispensable. If there is no clinical evidence of metastases, a sentinel lymph node biopsy is recommended. Essential columns of therapy are surgery, adjuvant or palliative radiotherapy and, in advanced inoperable stages, medicamentous tumor therapy. The introduction of immune checkpoint inhibitors has led to a paradigm shift, as they provide a considerably longer duration of response and better survival rates than chemotherapy. The PD-L1 inhibitor avelumab is approved for treatment of metastatic MCC in Germany, but the PD-1 antibodies pembrolizumab and nivolumab are also used with success. Adjuvant and neoadjuvant treatment concepts, immune combination therapies and targeted therapies as monotherapy or in combination with immune checkpoint inhibitors are in the clinical trial phase.

Chromosomal Aberrations Accumulate during Metastasis of Virus-Negative Merkel Cell Carcinoma

Merkel cell carcinoma is a rare, aggressive skin tumor initiated by polyomavirus integration or UV light DNA damage. In New Zealand, there is a propensity toward the UV-driven form (31 of 107, 29% virus positive). Using archival formalin-fixed, paraffin-embedded tissues, we report targeted DNA sequencing covering 246 cancer genes on 71 tumor tissues and 38 nonmalignant tissues from 37 individuals, with 33 of 37 being negative for the virus. Somatic variants of New Zealand virus-negative Merkel cell carcinomas partially overlapped with those reported overseas, including TP53 variants in all tumors and RB1, LRP1B, NOTCH1, and EPHA3/7 variants each found in over half of the cohort. Variants in genes not analyzed or reported in previous studies were also found. Cataloging variants in TP53 and RB1 from published datasets revealed a broad distribution across these genes. Chr 1p gain and Chr 3p loss were identified in around 50% of New Zealand virus-negative Merkel cell carcinomas, and RB1 loss of heterozygosity was found in 90% of cases. Copy number variants accumulate in most metastases. Virus-negative Merkel cell carcinomas have complex combinations of somatic DNA-sequence variants and copy number variants. They likely carry the small genomic changes permissive for metastasis from early tumor development; however, chromosomal alterations may contribute to driving metastatic progression.

Epidemiology of Merkel Cell Polyomavirus Infection and Merkel Cell Carcinoma

Merkel cell polyomavirus (MCPyV) is a ubiquitous virus replicating in human dermal fibroblasts. MCPyV DNA can be detected on healthy skin in 67−90% of various body sites, and intact virions are regularly shed from the skin. Infection occurs early in life, and seropositivity increases from 37 to 42% in 1- to 6-year-olds to 92% in adults. Merkel cell carcinoma (MCC) is a rare but very aggressive neuroendocrine tumor of the skin. It develops mainly on sun-exposed areas as a fast-growing, reddish nodule. Two MCC entities exist: about 80% of MCC are MCPyV-associated. Tumorigenesis is driven by viral integration into the host genome and MCPyV oncogene expression. In MCPyV-negative MCC, UV radiation causes extensive DNA damage leading to the deregulation of the cell cycle. In recent decades, MCC incidence rates have increased worldwide, e.g., in the United States, from 0.15 in 1986 to 0.7/100,000 in 2016. Risk factors for the development of MCC include male sex, older age (>75 years), fair skin, intense UV exposure, and immunosuppression. Projections suggest that due to aging populations, an increase in immunosuppressed patients, and enhanced UV exposure, MCC incidence rates will continue to rise. Early diagnosis and prompt treatment are crucial to reducing high MCC morbidity and mortality.

Synergistic targeting of the PI3K/mTOR and MAPK/ERK pathways in Merkel cell carcinoma

Merkel cell carcinoma (MCC) is an aggressive type of skin cancer, which is caused either by integration of the oncogenic Merkel cell polyomavirus (MCPyV) or by accumulation of UV-light induced mutations. Since the response to immune-checkpoint inhibitors is limited, new therapeutic agents need to be explored. Previous studies have shown that MCC cell lines and xenografts are sensitive to MLN0128, a dual mTOR1/2 inhibitor. Prompted by these results and considering that the PI3K/mTOR and MAPK/ERK pathways are the most commonly deregulated pathways in cancer, the combination of MLN0128 with the MEK1/2 inhibitor trametinib was investigated. Importantly, the combined targeting showed to be synergistic in MCC cell lines and induced alterations in the protein levels of downstream elements of the targeted pathways. This synergistic activity implies a reduction in the dose of each inhibitor necessary to reach the same effect that when used as single agents. Therefore, this is a promising approach to improve the clinical management of MCC and to overcome the limited efficacy of single drug regimens owed to the appearance of toxicity or drug resistance.

Activation of Oncogenic and Immune-Response Pathways Is Linked to Disease-Specific Survival in Merkel Cell Carcinoma

Simple Summary

Merkel cell carcinoma (MCC) is a rare and aggressive skin cancer. Developing targeted therapies for MCC requires increased understanding of the mechanisms driving tumor progression. In this study, we aimed to identify genes, signaling pathways, and processes that play crucial roles in determining disease-specific survival in MCC. We analyzed the gene expression of 102 MCC tumors and identified genes that were upregulated among survivors and in patients who died from MCC. We cross-referenced these genes with online databases to identify the pathways and processes in which they function. Genes upregulated among survivors were mostly immune response related and genes upregulated among patients who died from MCC function in various pathways that promote cancer progression. These results could guide future studies investigating whether these genes and pathways could be used as prognostic markers, as markers to guide therapy selection, or as targets of precision therapy in MCC.

Abstract

Background: Merkel cell carcinoma (MCC) is a rare but highly aggressive neuroendocrine carcinoma of the skin with a poor prognosis. Improving the prognosis of MCC by means of targeted therapies requires further understanding of the mechanisms that drive tumor progression. In this study, we aimed to identify the genes, processes, and pathways that play the most crucial roles in determining MCC outcomes. Methods: We investigated transcriptomes generated by RNA sequencing of formalin-fixed paraffin-embedded tissue samples of 102 MCC patients and identified the genes that were upregulated among survivors and in patients who died from MCC. We subsequently cross-referenced these genes with online databases to investigate the functions and pathways they represent. We further investigated differential gene expression based on viral status in patients who died from MCC. Results: We found several novel genes associated with MCC-specific survival. Genes upregulated in patients who died from MCC were most notably associated with angiogenesis and the PI3K-Akt and MAPK pathways; their expression predominantly had no association with viral status in patients who died from MCC. Genes upregulated among survivors were largely associated with antigen presentation and immune response. Conclusion: This outcome-based discrepancy in gene expression suggests that these pathways and processes likely play crucial roles in determining MCC outcomes.

Diagnosis and treatment of Merkel cell carcinoma: European consensus-based interdisciplinary guideline - Update 2022

Merkel cell carcinoma (MCC) is a rare skin cancer, accounting for less than 1% of all cutaneous malignancies. It is found predominantly in white populations and risk factors include advanced age, ultraviolet exposure, male sex, immunosuppression, such as AIDS/HIV infection, haematological malignancies or solid organ transplantation, and Merkel cell polyomavirus infection. MCC is an aggressive tumour with 26% of cases presenting lymph node involvement at diagnosis and 8% with distant metastases. Five-year overall survival rates range between 48% and 63%. Two subsets of MCC have been characterised with distinct molecular pathogenetic pathways: ultraviolet-induced MCC versus virus-positive MCC, which carries a better prognosis. In both subtypes, there are alterations in the retinoblastoma protein and p53 gene structure and function. MCC typically manifests as a red nodule or plaque with fast growth, most commonly on sun exposed areas. Histopathology (small-cell neuroendocrine appearance) and immunohistochemistry (CK20 positivity and TTF-1 negativity) confirm the diagnosis. The current staging systems are the American Joint Committee on Cancer/Union for international Cancer control 8th edition. Baseline whole body imaging is encouraged to rule out regional and distant metastasis. For localised MCC, first-line treatment is surgical excision with postoperative margin assessment followed by adjuvant radiation therapy (RT). Sentinel lymph node biopsy is recommended in all patients with MCC without clinically detectable lymph nodes or distant metastasis. Adjuvant RT alone, eventually combined with complete lymph nodes dissection is proposed in case of micrometastatic nodal involvement. In case of macroscopic nodal involvement, the standard of care is complete lymph nodes dissection potentially followed by post-operative RT. Immunotherapy with anti-PD-(L)1 antibodies should be offered as first-line systemic treatment in advanced MCC. Chemotherapy can be used when patients fail to respond or are intolerant for anti-PD-(L)1 immunotherapy or clinical trials.

Gender and immunosuppression impact on Merkel cell carcinoma diagnosis and prognosis. A population based cohort study

Background

Merkel cell carcinoma (MCC), a rare cutaneous neuroendocrine endocrine tumour is increasing in incidence, and continues to carry a poor prognosis.

Objectives

The objectives of this study were to examine all Irish cases of MCC from 1 January 1994 over 2 decades, focusing on gender and organ transplantation recipients (OTRs). Cases were identified from the National Cancer Registry of Ireland. Covariates of interest included age, body site, period of diagnosis, deprivation‐status and history of non‐melanoma skin cancer (NMSC).

Results

In total 314 MCC cases were identified. A female predominance was noted (53.8%). Comparison between age‐standardised rates between the earliest period (1994–1996) with the latest period (2012–2014) showed an increase of 105% in total. The trend in age‐standardised incidence rates were noted to be increasing significantly (p = 0.0004). Average age at diagnosis was 77.6 years (male 75.1 years, female 79.7 years). Overall, the majority of MCC cases presented on the head and neck (n = 170, 54.1%). Differences in anatomical location of MCCs were noted between genders. Males were found to be more likely to have a history of previous NMSCs (males n = 73 [57.9%], females n = 53 [42.1%]). Thirty‐one percentage of patients died from MCC, average survival was 3.5 years in those who died of this malignancy. Ten organ transplant recipients developed MCC. OTR who developed MCC were diagnosed at a younger average age of 65.1 years. Standardized incidence ratio for MCC in OTR was 59.96. A higher proportion of OTR died from MCC (70%), with a shorter median survival of 0.14 years. In competing risks regression, gender was not significantly associated with risk of dying, females having a non‐significantly higher hazard of dying. Organ transplant recipients and patients from less deprived areas were at greater risk of dying from MCC.

Conclusions

This population based study provides epidemiological, clinical and outcome data for MCC over a 20‐year period.

International Increases in Merkel Cell Carcinoma Incidence Rates between 1997 and 2016

Relatively little is known about the epidemiology of Merkel cell carcinoma (MCC) with regard to international trends in incidence, specifically relating to differences by age, sex, and anatomic site. We examined the trends in sex-specific incidence of MCC in the United States, Australia, New Zealand, Scotland, and Norway over a 20-year period (1997-2016) as well as the site-specific incidence trends in the United States. We used Joinpoint regression models to estimate the average annual percentage change in the incidence. In the total United States population, we observed an average annual percentage change of 2.7% (95% confidence interval [CI] = 2.0-3.3) for MCC, with sex-specific incidence increasing from 0.55 to 1.03 per 100,000 in men and from 0.28 to 0.45 per 100,000 in women. MCC incidence also increased in Queensland, Australia (average annual percentage change 1.8%, 95% CI = 0.7-2.8), New Zealand (2.0%, 95% CI = 0.4-3.7), Scotland (3.7%, 95% CI = 2.0-5.5), and Norway (4.0%, 95% CI = 2.1-5.9). In all populations, MCC incidence was higher in men than in women. Between 1993 and 2016 in the United States, the incidence of MCC of the head and neck and upper and lower limbs increased in both sexes. Despite being an uncommon malignancy, our analyses show that MCC incidence is steadily increasing both in areas of low and those of high ambient UVR levels.

Emerging cancer incidence, mortality, hospitalisation and associated burden among Australian cancer patients, 1982 - 2014: an incidence-based approach in terms of trends, determinants and inequality

OBJECTIVE

Cancer is a leading killer worldwide, including Australia. Cancer diagnosis leads to a substantial burden on the individual, their family and society. The main aim of this study is to understand the trends, determinants and inequalities associated with cancer incidence, hospitalisation, mortality and its burden over the period 1982 to 2014 in Australia.

SETTINGS

The study was conducted in Australia.

STUDY DESIGN

An incidence-based study design was used.

METHODS

Data came from the publicly accessible Australian Institute of Health and Welfare database. This contained 2 784 148 registered cancer cases over the study period for all types of cancer. Erreygers' concentration index was used to examine the magnitude of socioeconomic inequality with regards to cancer outcomes. Furthermore, a generalised linear model was constructed to identify the influential factors on the overall burden of cancer.

RESULTS

The results showed that cancer incidence (annual average percentage change, AAPC=1.33%), hospitalisation (AAPC=1.27%), cancer-related mortality (AAPC=0.76%) and burden of cancer (AAPC=0.84%) all increased significantly over the period. The same-day (AAPC=1.35%) and overnight (AAPC=1.19%) hospitalisation rates also showed an increasing trend. Further, the ratio (least-most advantaged economic resources ratio, LMR of mortality (M) and LMR of incidence (I)) was especially high for cervix (M/I=1.802), prostate (M/I=1.514), melanoma (M/I=1.325), non-Hodgkin's lymphoma (M/I=1.325) and breast (M/I=1.318), suggesting that survival inequality was most pronounced for these cancers. Socioeconomically disadvantaged people were more likely to bear an increasing cancer burden in terms of incidence, mortality and death.

CONCLUSIONS

Significant differences in the burden of cancer persist across socioeconomic strata in Australia. Policymakers should therefore introduce appropriate cancer policies to provide universal cancer care, which could reduce this burden by ensuring curable and preventive cancer care services are made available to all people.