Merkel Cell Carcinoma

Evolving Role of Sentinel Lymph Node Biopsy for Melanoma, Merkel Cell, and Squamous Cell Carcinoma

Technical advances in lymphoscintigraphy, pathologic immunostaining, and intra-operative mapping in the setting of level 1 evidence have led to the adoption of sentinel lymph node biopsy as an accurate minimally invasive staging procedure. Currently, the procedure is recommended in select melanoma, all merkel cell carcinoma, and high-risk squamous cell carcinoma patients with clinically negative lymph nodes. In the future, ongoing discoveries in cutaneous oncology pathogenesis, systemic therapy, and predictive biomarkers research may allow for further data-driven evolution in the care of these patients to maximize survival and quality of life while minimizing morbidity of multimodal cancer therapy.

Patient Characteristics and Outcomes in Clinically Misdiagnosed Patients With Merkel Cell Carcinoma

INTRODUCTION

Merkel cell carcinoma (MCC) is a rare aggressive cutaneous neuroendocrine carcinoma characterized by poor outcomes. MCC morphology is nonspecific and mimics that of other skin lesions, resulting in misdiagnosis and delayed treatment. This study aims to describe survival outcomes of patients with MCC who were clinically misdiagnosed.

METHODS

Patients diagnosed with MCC were identified using a single-institution retrospective database. Demographics, tumor characteristics, and diagnostic features were evaluated. The Kaplan-Meier method was used to estimate overall survival and recurrence-free survival.

RESULTS

Out of 109 patients with MCC, 96 (88.1%) were initially misdiagnosed based on clinical examination before histopathological confirmation of MCC. Common misdiagnoses included basal cell carcinoma (n = 32, 29.4%), squamous cell carcinoma (n = 23, 21.1%), and benign cyst (n = 21, 19.3%). Misdiagnosed patients had a larger median tumor size of 1.8 cm, whereas correctly diagnosed patients had a median tumor size of 1.5 cm. Patients with correct initial diagnosis tended to have negative nodal disease (87.5% versus. 50.0%) and early-stage disease (stage I-II: 76.9% versus. 44.7%). Patients who were misdiagnosed had a lower median overall survival compared to those who were not (74.6 mo versus. 120.6 mo, P = 0.414). Median recurrence-free survival among those who were misdiagnosed was 52.6 mo, whereas it was not reached in the correctly diagnosed group (P = 0.068).

CONCLUSIONS

The nonspecific appearance of MCC poses diagnostic challenges in nonacademic health care settings. Given that patients who were clinically misdiagnosed had worse survival, heightened awareness of MCC and early referral to tertiary medical centers are crucial to ensuring optimal patient outcomes for this rare disease.

Non-Genetic Biomarkers in Merkel Cell Carcinoma: Prognostic Implications and Predictive Utility for Response to Anti-PD-(L)1 Immune Checkpoint Inhibitors

Merkel cell carcinoma (MCC) is a skin cancer that arises due to either Merkel cell polyomavirus infection (MCPyV) or ultraviolet (UV) radiation exposure, presenting primarily in the head and neck region of fair-skinned males. The recent success of PD-(L)1 immune checkpoint inhibitors (ICIs) in locally advanced/metastatic MCC, with an objective response rate (ORR) around 50% and improved survival, as a first-line treatment has moved ICIs to the forefront of therapy for MCC and generated interest in identifying biomarkers to predict clinical response. The MCC tumour microenvironment (TME) contains various components of the adaptive and innate immune system. These components can contribute to tumour immune escape through immunosuppression by preventing entrance of other immune cells or by aiding in the cytotoxic clearance of tumour cells. We aim to combine information from studies of baseline and on-treatment monitoring of the TME to help predict the success of ICIs in MCC. This review enhances the understanding of how CD8 T cells, γδ T cells and macrophages may impact predictions of response rates to ICIs in MCC patients. These immune cells are non-genetic biomarkers that can also be used to determine prognosis in MCC treatment.

Profound ctDNA and radiological responses after 2 cycles of avelumab in a metastatic Merkel cell carcinoma of the head and neck

BACKGROUND

Merkel cell carcinoma (MCC) is an uncommon skin cancer that in more than 90 % of cases develops within the head and neck region. MCC is an aggressive disease with a dismal prognosis before the advent of immunotherapy. Avelumab, an anti-PDL1 agent is approved since 2017 for the treatment of advanced MCC after demonstrating a high response rate and favorable impact in survival.

METHODS

Next generation sequencing (NGS) of the primary tumor biopsy from initial diagnosis (Foundation One CDx, Roche Diagnostics) as well as from plasma samples (Foundation One Liquid, Roche Diagnostics) obtained before and during treatment with avelumab were performed.

RESULTS

We present the case of a patient with a metastatic MCC developing in the left parotid gland / pre-auricular area in an 80-year-old male with a long-lasting history of high UV exposure. After two cycles of avelumab 10 mg/kg/q2wk a near complete metabolic response and a major radiological response occurred in parallel to a brisk reduction in the ctDNA tumor fraction as well as variant-allele frequencies (VAFs) of all the mutations detected before the start of avelumab.

CONCLUSION

Avelumab may achieve rapid and major responses in metastatic MCC. Our study demonstrates that ctDNA mirrors radiological responses and may serve as an ideal companion for diagnosis and disease monitoring in MCC.

High-Risk Non-Melanoma Skin Cancers: Biological and Therapeutic Advances

Nonmelanoma skin cancers (NMSCs) are the most common cancers, with high-risk NMSCs sharing features such as poor histologic differentiation, invasion into deeper layers, and anatomic location. NMSC includes basal cell carcinoma, cutaneous squamous cell carcinoma, and Merkel cell carcinoma. Herein, the authors describe advances in understanding the genetic mechanisms of malignant transformation and the composition of tumor microenvironment for these cancers. They summarize recent therapeutic advances, including targeted therapy and immunotherapy for NMSCs. Effective skin protection against ultraviolet radiation-induced carcinogenesis remains an urgent unmet need for NMSC prevention. The authors highlight immune-based interventions as novel strategies to address this need.

Food and Drug Administration (FDA) Approvals of Biological Drugs in 2023

An increase in total drug (small molecules and biologics) approvals by the Food and Drug Administration (FDA) was seen in 2023 compared with the previous year. Cancer remained the disease most targeted by monoclonal antibodies (mAbs), followed by autoimmune conditions. Our data reveal the prevalence of approvals for biologics even during years when the total number of authorizations was low, such as in 2022. Over half the drugs that received the green light in 2023 benefited from expedited programs, as the incidence of many diseases increased. In addition, over half of the biologics approved received Orphan Drug Designation from the FDA. This narrative review delves into details of the most significant approvals in 2023, including mAbs, enzymes, and proteins, explaining their mechanisms of action, differences from previous drugs, placebo, and standards of care, and outcomes in clinical trials. Given the varying number of drugs authorized annually by the U.S. health authority, this review also examines the limits of external influences over the FDA's decisions and independence regarding drug approvals and withdrawals.

Rubella virus chronic inflammatory disease and other unusual viral phenotypes in inborn errors of immunity

Infectious susceptibility is a component of many inborn errors of immunity. Nevertheless, antibiotic use is often used as a surrogate in history taking for infectious susceptibility, thereby disadvantaging patients who present with viral infections as their phenotype. Further complicating clinical evaluations are unusual manifestations of viral infections which may be less familiar that the typical respiratory viral infections. This review covers several unusual viral phenotypes arising in patients with inborn errors of immunity and other settings of immune compromise. In some cases, chronic infections lead to oncogenesis or tumor-like growths and the conditions and mechanisms of viral-induced oncogenesis will be described. This review covers enterovirus, rubella, measles, papillomavirus, and parvovirus B19. It does not cover EBV and hemophagocytic lymphohistiocytosis nor lymphomagenesis related to EBV. EBV susceptibility has been recently reviewed. Our goal is to increase awareness of the unusual manifestations of viral infections in patients with IEI and to describe treatment modalities utilized in this setting. Coincidentally, each of the discussed viral infections can have a cutaneous component and figures will serve as a reminder of the physical features of these viruses. Given the high morbidity and mortality, early recognition can only improve outcomes.

Exploring diagnosis and therapeutic complexities of an aggressive Merkel cell carcinoma: A case report and review of the literature

Merkel cell carcinoma (MCC) is an aggressive and rare cutaneous neuroendocrine carcinoma that predominantly affects the sun-damaged skin of the head and neck region, extremities, and trunk of older white individuals. Microscopically, MCC is characterized by nests or sheets of uniform small round blue cells with scant cytoplasm, granular nuclei with a salt-and-pepper chromatin pattern, high proliferative activity, and occasional necrosis. They are usually positive for epithelial and neuroendocrine markers, particularly for cytokeratin 20 and AE1/AE3 in a paranuclear dot-like staining. We herein contribute by reporting a case of MCC affecting the auricular pavilion of a 66-year-old female patient from Campinas, Brazil. Additionally, a review of the current literature is also included to analyze all the cases that have been reported in the English-language literature, totalizing 27 cases of MCC on the external ear. The 5-year overall survival rate for individuals with localized MCC is 50% and the most common treatment choice is the combination of surgery with adjuvant radiotherapy and sentinel lymph node biopsy.

Avelumab for Advanced Merkel Cell Carcinoma: Global Real-World Data on Patient Response and Survival

Introduction

Avelumab is a programmed cell death-ligand 1 (PD-L1) inhibitor approved by the Food and Drug Administration for advanced Merkel cell carcinoma (MCC). Studies conducted in real-world settings have shed light on its effectiveness and safety in clinical settings.

Areas Covered

Real-world studies on avelumab for MCC from North and South America, Europe, and Asia have been presented in this review. Most studies are on patients over age 70 and have a male-predominant sex ratio. Overall response rates range from 29.1% to 72.1%, (disease control rate: 60.0-72.7%; complete response rate: 15.8%-37.2%; partial rate: 18.2-42.1%; stable disease: 7.1-30.9%; progressive disease: 7.1-40.0%) and median progression free survival ranges from 8.1 to 24.1 months depending on the population studied. Immunosuppressed patients appear to benefit from avelumab as well, with response rates equivalent to the general population. Patients receiving avelumab as a first-line agent tend to have better outcomes than those using it as a second-line therapy. Fatigue, infusion-related reactions, and dyspnea were some of the most common adverse events identified in real-world studies. Autoimmune hepatitis and thyroiditis were also observed.

Conclusion

The use of avelumab as a safe and effective treatment option for advanced MCC is supported by real-world data, although additional study is required to assess long-term efficacy and safety outcomes.

Overall Survival After Mohs Surgery for Early-Stage Merkel Cell Carcinoma

Importance

Merkel cell carcinoma (MCC) is a rare cutaneous malignant neoplasm with increasing incidence and high mortality. Although it is accepted that the optimal treatment for localized tumors is surgical, the data surrounding the optimal surgical approach are mixed, and current National Comprehensive Cancer Network guidelines state that Mohs micrographic surgery (MMS) and wide local excision (WLE) can both be used. The current National Comprehensive Cancer Network guidelines do not advocate a preference for MMS or WLE and suggest that they can be used interchangeably.

Objective

To evaluate the association of surgical approach with overall survival after excision of localized T1/T2 MCC.

Design, Setting, and Participants

This retrospective cohort study used the National Cancer Database to assess adults with T1/T2 MCC who were diagnosed between January 1, 2004, and December 31, 2018, with pathologically confirmed, negative regional lymph nodes and treated with surgery. The National Cancer Database includes all reportable cases from Commission on Cancer-accredited facilities. Data analysis was performed from October 2022 to May 2023.

Exposure

Surgical approach.

Main Outcomes and Measures

Overall survival.

Results

A total of 2313 patients (mean [SD] age, 71 [10.6] years; 1340 [57.9%] male) were included in the study. Excision with MMS had the best unadjusted survival, with mean (SE) survival rates of 87.4% (3.4%) at 3 years, 84.5% (3.9%) at 5 years, and 81.8% (4.6%) at 10 years vs 86.1% (0.9%) at 3 years, 76.9% (1.2%) at 5 years, and 60.9% (2.0%) at 10 years for patients treated with WLE. Patients treated with narrow-margin excision had similar survival as those treated with WLE, with mean (SE) survival rates of 84.8% (1.4%) at 3 years, 78.3% (1.7%) at 5 years, and 60.8% (3.6%) at 10 years. On multivariable survival analysis, excision with MMS was associated with significantly improved survival compared with WLE (hazard ratio, 0.59; 95% CI, 0.36-0.97; P = .04). High-volume MCC centers were significantly more likely to use MMS over WLE compared with other centers (odds ratio, 1.99; 95% CI, 1.63-2.44; P < .001).

Conclusions and Relevance

In this cohort study, the use of MMS (compared with WLE) was associated with significantly improved survival for patients with localized MCC with pathologically confirmed negative lymph nodes treated with surgery. These data suggest that Mohs surgery may provide a more effective treatment for MCC primary tumors than conventional WLE, although the lack of randomization and potential for selection bias in this study highlight the need for future prospective work evaluating this issue.

Case report: Metastasis of Merkel cell carcinoma in the small intestine

Merkel cell carcinoma is a rare primary neuroendocrine malignant neoplasm of the skin, which recurs in about 40 % of cases. The main factors are Merkel cell polyomavirus (MCPyV) and mutations caused by ultraviolet radiation [Paulson, 2018]. In this study, we report a case of Merkel cell carcinoma with metastasis to the small intestine. In a 52-year-old woman, a subcutaneous formation of a nodule up to 2.0 cm in diameter was detected during the examination. This neoplasm was removed and sent for histological analysis. Dot-like expression of CK pan, CK 20, chromogranin A, and Synaptophysin was observed in tumor cells, and Ki-67 in 40 % of tumor cells. There is no reaction in tumor cells to CD 45, CK 7, TTF 1, and S100. The morphological picture corresponded to Merkel cell carcinoma. A year later, the patient underwent surgery for intestinal obstruction. The pathohistological changes and immunophenotype of the small bowel tumor were consistent with Merkel cell carcinoma metastasis.