Demographics and outcomes of stage I and II Merkel cell carcinoma treated with Mohs micrographic surgery compared with wide local excision in the National Cancer Database

Primary tumor site for localized Merkel cell carcinoma drives different management strategies without impacting oncologic outcomes

BACKGROUND AND PURPOSE

Clinically localized Merkel cell carcinoma (MCC) has been associated with high rates of disease relapse. This study examines how primary tumor anatomic site drives patterns of care and outcomes in a large cohort treated in the contemporary era.

MATERIALS AND METHODS

Patterns of care and associated outcomes were evaluated for clinically Stage I-II MCC patients treated at our institution with adjuvant radiation therapy (RT) to the primary site and/or regional nodal basin as a component of their curative intent therapy between 2014-2021.

RESULTS

Of 80 patients who met inclusion criteria, the primary tumor anatomic site was head and neck (HN) for 42 (53%) and non-head and neck (NHN) for 38 (47%). Primary tumor risk factors were similar between cohorts. Fewer patients with HN tumors had wide local excision (WLE; HN-81% vs. NHN-100% p < 0.01). Of those undergoing WLE, patients with HN tumors received higher dose adjuvant RT (>50 Gy: HN-70% vs. NHN-8%; p < 0.01). Patients with HN tumors were less likely to undergo sentinel lymph node biopsy (HN-62%vs. NHN-100%; p < 0.01) and more likely to have elective nodal RT (HN-48% vs. NHN-0%). Despite varying management strategies, there was no significant difference in local recurrence-free survival (3-yr LRFS HN-94% vs. NHN-94%; p = 0.97), nodal recurrence-free survival (3-yr NRFS HN-89% vs. NHN-85%; p = 0.71) or overall recurrence-free survival (3-yr RFS 73% HN vs. 80% NHN; p = 0.44).

CONCLUSIONS

Among patients with primary MCC who had RT as a component of their initial treatment strategy, anatomically-driven heterogeneous treatment approaches were associated with equally excellent locoregional disease control.

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.

Survival Outcomes of Mohs Surgery versus Wide Local Excision for Less Common Nonmelanoma Skin Cancers: A Stabilized Inverse Probability of Treatment Weighting Analysis

BACKGROUND

Compared with wide local excision (WLE), Mohs micrographic surgery (MMS) can not only remove the tumor tissue but also ensure a negative margin. However, there is limited evidence on whether there is a difference in prognosis between the two techniques for less common nonmelanoma skin cancers (NMSCs).

OBJECTIVES

The aim of our study was to compare the survival outcomes of MMS and WLE for less common NMSCs.

METHODS

This study retrospectively analyzed data from the Surveillance, Epidemiology, and End Results dataset between 2003 and 2018. The less common NMSCs include Merkel cell carcinoma, skin appendage neoplasm, fibromatous malignancy, and other rare NMSCs. The stabilized inverse probability of treatment weighting (SIPTW) and the Kaplan-Meier methods were adopted to assess the overall survival (OS) and cancer-specific survival (CSS). Furthermore, the Cox proportional hazards, Fine-and-Gray regression analysis, and subgroup analysis models were applied to examine the effects of MMS versus WLE based on all-cause and cancer-specific mortality.

RESULTS

We identified 6,582 individuals with less common NMSCs for survival analysis, among which 1,946 patients (29.5%) had undergone MMS and 4,636 (70.5%) had received WLE. Diseases diagnosed in the most recent year, older age, the White race, married status, eyelid/face site, small tumor size, and localized disease were factors significantly associated with MMS treatment. Compared with the WLE group, the MMS group had comparable OS before and after the SIPTW analysis. Additionally, after adjusting for other confounding covariates, the surgery type (WLE vs. MMS) did not show significant associations with all-cause mortality (hazard ratio [HR]: 1.03, 95% confidence interval [CI]: 0.94-1.14, p = 0.517) and disease-specific mortality (HR: 1.16, 95% CI: 0.95-1.42, p = 0.134). Moreover, the subgroup analysis validated these findings.

CONCLUSION

MMS and WLE have comparable OS and CSS for less common NMSCs.

The Evolving Treatment Landscape of Merkel Cell Carcinoma

OPINION STATEMENT

Merkel cell carcinoma (MCC) has a high risk of recurrence and requires unique treatment relative to other skin cancers. The patient population is generally older, with comorbidities. Multidisciplinary and personalized care is therefore paramount, based on patient preferences regarding risks and benefits. Positron emission tomography and computed tomography (PET-CT) is the most sensitive staging modality and reveals clinically occult disease in ~ 16% of patients. Discovery of occult disease spread markedly alters management. Newly diagnosed, localized disease is often managed with sentinel lymph node biopsy (SLNB), local excision, primary wound closure, and post-operative radiation therapy (PORT). In contrast, metastatic disease is usually treated systemically with an immune checkpoint inhibitor (ICI). However, one or more of these approaches may not be indicated. Criteria for such exceptions and alternative approaches will be discussed. Because MCC recurs in 40% of patients and early detection/treatment of advanced disease is advantageous, close surveillance is recommended. Given that over 90% of initial recurrences arise within 3 years, surveillance frequency can be rapidly decreased after this high-risk period. Patient-specific assessment of risk is important because recurrence risk varies widely (15 to > 80%: Merkelcell.org/recur) depending on baseline patient characteristics and time since treatment. Blood-based surveillance tests are now available (Merkel cell polyomavirus (MCPyV) antibodies and circulating tumor DNA (ctDNA)) with excellent sensitivity that can spare patients from contrast dye, radioactivity, and travel to a cancer imaging facility. If recurrent disease is locoregional, management with surgery and/or RT is typically indicated. ICIs are now the first line for systemic/advanced MCC, with objective response rates (ORRs) exceeding 50%. Cytotoxic chemotherapy is sometimes used for debulking disease or in patients who cannot tolerate ICI. ICI-refractory disease is the major problem faced by this field. Fortunately, numerous promising therapies are on the horizon to address this clinical need.

[Micrographic controlled surgery in everyday dermatosurgery]

Micrographic controlled surgery (MCS) has become established in dermatosurgery in recent years and includes various methods to enable the histologically proven complete resection of malignant cutaneous tumors, while at the same time sparing tumor-free tissue in the immediate vicinity as much as possible. MCS is of great importance in the surgical treatment of cutaneous malignancies in so-called problem locations and aggressive tumor subtypes. Indications for MCS include basal cell carcinoma, cutaneous squamous cell carcinoma, Bowen's disease and Bowen's carcinoma, melanoma in chronic light-damaged skin with acral lentiginous melanoma, dermatofibrosarcoma protuberans (DFSP), and Merkel cell carcinoma. However, other tumor entities are also treated using MCS, such as extramammary Paget's disease and various cutaneous sarcomas. All procedures subsumed under MCS have in common the marking of the surgical specimen for topographical orientation, which provides assignment of remaining tumor remnants. Various methods of MCS (3D histology, the horizontal method or Mohs surgery) are presented in this article. Furthermore, this article aims to raise awareness of the possibilities and limitations of micrographically controlled surgery.

Merkel Cell Carcinoma of the Head and Neck

Merkel cell carcinoma (MCC) of the head and neck is a rare and aggressive non-melanoma skin cancer. The objective of this study was to assess the oncological outcome of MCC by retrospective review of electronic and paper records of a population-based cohort of 17 consecutive cases of the head and neck MCC without distant metastasis, diagnosed in Manitoba between 2004 and 2016. The average age of the patients at initial presentation was 74.1 ± 14.4 years with 6 patients presenting with stage I, 4 with stage II, and 7 with stage III disease. Both surgery or radiotherapy alone were the primary treatment modalities in 4 patients each and the remaining 9 patients had a combination of surgery with adjuvant radiotherapy. During the median follow-up of 52 months, 8 patients had recurrent/residual disease and 7 eventually died of it (P = .001). Metastatic spread of disease to the regional lymph nodes was observed in 11 patients either at presentation or during the follow-up and to the distant sites in 3 patients. At the time of the last contact on November 30, 2020, 4 patients were alive and disease-free, 7 had died of disease, and 6 had died of other causes. The case fatality rate was 41.2%. Five-year disease-free and disease-specific survivals were 51.8% and 59.7%, respectively. The 5-year disease-specific survival was 75% for early stage MCC (stage I and II) and 35.7% for stage III MCC. Early diagnosis and intervention are crucial for disease control and improving survival.

An update on Merkel cell carcinoma

Merkel cell carcinoma (MCC) is a rare cancer of the skin characterized by a neuroendocrine phenotype and an aggressive clinical behavior. It frequently originates in sun-exposed body areas, and its incidence has steadily increased in the last three decades. Merkel cell polyomavirus (MCPyV) and ultraviolet (UV) radiation exposure are the main causative agents of MCC, and distinct molecular features have been documented in virus-positive and virus-negative malignancies. Surgery remains the cornerstone of treatment for localized tumors, but even when integrated with adjuvant radiotherapy is able to definitively cure only a fraction of MCC patients. While characterized by a high objective response rate, chemotherapy is associated with a short-lasting benefit of approximately 3 months. On the other hand, immune checkpoint inhibitors including avelumab and pembrolizumab have demonstrated durable antitumor activity in patients with stage IV MCC, and investigations on their use in the neoadjuvant or adjuvant setting are currently underway. Addressing the needs of those patients who do not persistently benefit from immunotherapy is currently one of the most compelling unmet needs in the field, and multiple clinical trials of new tyrosine kinase inhibitors (TKIs), peptide receptor radionuclide therapy (PRRT), therapeutic vaccines, immunocytokines as well as innovative forms of adoptive cellular immunotherapies are under clinical scrutiny at present.

Merkel cell carcinoma: epidemiology, clinical features, diagnosis and treatment of a rare disease

Merkel cell carcinoma is a rare skin cancer with neuroendocrine differentiation. The risk factors include sun exposure, advanced age, immunosuppression (such as transplant recipients, patients with lymphoproliferative neoplasms, or patients with HIV), and Merkel cell polyomavirus infection. Clinically, Merkel cell carcinoma appears as a cutaneous or subcutaneous plaque or nodule, but this tumor diagnosis is rarely made clinically. Therefore, histopathology and immunohistochemistry are usually necessary. Primary tumors without evidence of metastases are treated with complete surgical excision and appropriate surgical margins. The presence of occult metastasis in a lymph node is frequent and a sentinel lymph node biopsy should be performed. Postoperative adjuvant radiotherapy increases local tumor control. Recently, agents that block the PD-1/PD-L1 pathway have shown objective and durable tumor regression in patients with advanced solid malignancies. The first anti-PD-L1 antibody used in patients with Merkel cell carcinoma was avelumab, but pembrolizumab and nivolumab have also shown efficacy. This article describes the current state of knowledge of the epidemiology, diagnosis, and staging of Merkel cell carcinoma, as well as new strategies for its systemic treatment.

S2k Guideline - Merkel cell carcinoma (MCC, neuroendocrine carcinoma of the skin) - Update 2022

Merkel cell carcinoma (MCC, ICD-O M8247/3) is a rare, malignant, primary skin tumor with epithelial and neuroendocrine differentiation. The tumor cells share many morphologic, immunohistochemical, and ultrastructural features with cutaneous Merkel cells. Nevertheless, the cell of origin of MCC is unclear. MCC appears clinically as a reddish to purple spherical tumor with a smooth, shiny surface and a soft to turgid, elastic consistency, usually showing rapid growth. Spontaneous and often complete regressions of the tumor are observed. These likely immunologically-mediated regressions explain the cases in which only lymph node or distant metastases are found at the time of initial diagnosis and why the tumor responds very well to immunomodulatory therapies even at advanced stages. Due to its aggressiveness, the usually given indication for sentinel lymph node biopsy, the indication of adjuvant therapies to be evaluated, as well as the complexity of the necessary diagnostics, clinical management should already be determined by an interdisciplinary tumor board at the time of initial diagnosis.

Best practices in surgical and nonsurgical management of head and neck Merkel cell carcinoma: An update

Merkel cell carcinoma (MCC) is a rare, highly aggressive cutaneous neuroendocrine carcinoma. Controversy exists regarding optimal management of MCC as high-quality randomized studies and clinical trials are limited, and physicians are bound to interpret highly heterogeneous, retrospective literature in their clinical practice. Furthermore, the rising incidence and notably poor prognosis of MCC urges the establishment of best practices for optimal management of the primary tumor and its metastases. Herein, we summarized the relevant evidence and provided an algorithm for decision-making in MCC management based on the latest 2021 National Comprehensive Cancer Network guidelines. Additionally, we report current active MCC clinical trials in the United States. The initial management of MCC is dependent upon the pathology of the primary tumor and presence of metastatic disease. Patients with no clinical evidence of regional lymph node involvement generally require sentinel node biopsy (SLNB) while clinically node-positive patients should undergo fine needle aspiration (FNA) or core biopsy and full imaging workup. If SLNB or FNA/core biopsy are positive, a multidisciplinary team should be assembled to discuss if additional node dissection or adjuvant therapy is necessary. Wide local excision is optimal for primary tumor management and SLNB remains the preferred staging and predictive tool in MCC. The management of MCC has progressively improved in the last decade, particularly due to the establishment of immunotherapy as a new treatment option in advanced MCC. Ongoing trials and prospective studies are needed to further establish the best practices for MCC management.

Mohs Micrographic Surgery for Facial Merkel Cell Carcinoma

BACKGROUND

Merkel cell carcinoma (MCC) is a rare malignant cutaneous tumor with frequent metastases. They often appear in the face where cosmetic and functional outcome is critical. Mohs micrographic surgery (MMS) is a controlled intervention that optimizes negative margins without sacrificing tissue.

OBJECTIVE

A comprehensive assessment of outcomes of MMS-treated facial MCC will help guide clinicians in surgical and medical management.

METHODS & MATERIALS

Retrospective review identified facial MCC cases treated with MMS at a single institution from January 2005 to August 2020. Tumor characteristics and outcomes were recorded and descriptive and predictive analyses were performed.

RESULTS

34 cases were reviewed with a mean followup of 34.4 months. The most common sites were the forehead, cheek-jaw region, and nasal ala. 2 (5.9%) patients had local recurrence by a mean of 4.3 months. No documented variables were significantly associated with local recurrence. 8 (23.5%) patients had progression to metastasis by a mean of 9.4 months. Younger age at biopsy and surgery, male sex, and intraoperative detection of in-transit disease were significantly associated with progression to metastasis.

CONCLUSIONS

In summary, the tissue-sparing approach of MMS may be beneficial for MCC in cosmetically and functionally sensitive facial locations as it preserves tissue without compromising outcomes.

Merkel Cell Carcinoma-Update on Diagnosis, Management and Future Perspectives

MCC is a rare but highly aggressive skin cancer. The identification of the driving role of Merkel cell polyomavirus (MCPyV) and ultraviolet-induced DNA damage in the oncogenesis of MCC allowed a better understanding of its biological behavior. The presence of MCPyV-specific T cells and lymphocytes exhibiting an 'exhausted' phenotype in the tumor microenvironment along with the high prevalence of immunosuppression among affected patients are strong indicators of the immunogenic properties of MCC. The use of immunotherapy has revolutionized the management of patients with advanced MCC with anti-PD-1/PD L1 blockade, providing objective responses in as much as 50-70% of cases when used in first-line treatment. However, acquired resistance or contraindication to immune checkpoint inhibitors can be an issue for a non-negligible number of patients and novel therapeutic strategies are warranted. This review will focus on current management guidelines for MCC and future therapeutic perspectives for advanced disease with an emphasis on molecular pathways, targeted therapies, and immune-based strategies. These new therapies alone or in combination with anti-PD-1/PD-L1 inhibitors could enhance immune responses against tumor cells and overcome acquired resistance to immunotherapy.

Treatment and survival outcomes in metastatic Merkel cell carcinoma: Analysis of 2010 patients from the SEER database

INTRODUCTION

Merkel cell carcinoma (MCC) is an aggressive cutaneous cancer that frequently compromises the lymph nodes (LN) and distal organs. We sought to describe clinical and demographic characteristics of affected patients, analyze risk factors for LN compromise, metastasis, and death, and evaluate their impact on survival.

MATERIALS AND METHODS

Patients with MCC were retrieved from the SEER database. Demographic, clinical and treatment data were analyzed. Logistic and Cox proportional hazard regression were used to analyze risk factors. Survival analysis was done with the Kaplan-Meier method.

RESULTS

A total of 2010 patients were included, among which 288 (14.33%) had distant metastases at diagnosis. LN involvement occurred in 45.8% and 20.1% of patients with and without distant metastasis, respectively. Males were more likely to present LN compromise (OR = 1.33, p<0.001). Tumors >10 mm showed a significantly higher risk for LN involvement and distant metastasis, with those >20 mm showing the highest risk (OR = 2.76 p<0.001 and OR = 8.88 p<0.001 respectively). Location of the tumor in the trunk was a protective factor for overall death (OR = 0.27), while LN compromise was a risk factor (OR = 3.12). Only history of previous malignancy significantly affected disease-specific death (OR = 0.32, p = 0.01). One-year survival was 79.7% and 38.2% for patients with regional LN disease and distant metastasis, respectively.

CONCLUSION

MCC is an aggressive cancer with high rates of LN involvement and distant metastases. Male gender and tumor size were risk factors for regional LN and metastatic disease. Tumor location in the trunk decrease the risk of overall death, while LN involvement increased it.

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.

An update on local and systemic therapies for non-melanoma skin cancer

INTRODUCTION

Nonmelanoma skin cancers (NMSC) as a group exceed the incidence of all other malignancies combined. NMSC includes basal cell carcinoma, squamous cell carcinoma, and Merkel cell carcinoma. As the incidence continues to rise, it is important to appreciate the available treatment options.

AREAS COVERED

This article discusses the treatment of NMSC though surgical, topical, regional, and systemic modalities.

EXPERT OPINION

As there are many treatment options available for these diseases, selection of the appropriate method can be difficult. With time, we expect treatment decisions to become even more complex and personalized. The role of systemic immunotherapies and neoadjuvant therapies in the treatment of NMSC is still not well defined. Local treatment with intralesional injections and isolated limb infusion may prove to be promising alternative therapies.

Merkel Cell Carcinoma, the Impact of Clinical Excision Margins and Mohs Micrographic Surgery on Recurrence and Survival: A Systematic Review

BACKGROUND

When treating Merkel cell carcinoma (MCC), the relation between wide local excision (WLE) margin and recurrence or survival is unclear. Mohs micrographic surgery (MMS) is an alternative surgical option for MCC, but it is unknown whether the local recurrence rate differs between MMS and WLE.

OBJECTIVE

To systematically assess the available literature to determine the recurrence and survival rates when treating MCC with MMS and different clinical excision margins.

MATERIALS AND METHODS

The MEDLINE, EMBASE, and CENTRAL databases were searched. Two independent reviewers selected studies that defined clear excision margins and either recurrence or survival. When possible, individual cases were extracted from case series and included in the analyses. Other studies were reviewed narratively.

RESULTS

Overall, 1108 studies were identified; of which, 19 case series (168 cases) and 12 cohort studies were eligible. None of the cohort studies showed significant differences in recurrence or survival for either excision margins or MMS. Equally, logistic and Cox regression analyses of the case series revealed no significant differences in recurrence or survival between different excision margins and MMS.

CONCLUSION

Synthesis of the available data does not indicate differences in recurrence and/or survival rates for MCC between different clinical excision margins and MMS.

Predictors of Time to Definitive Surgery and Survival in Merkel Cell Carcinoma: Analysis of National Cancer Database

BACKGROUND

Effects of delays in treatment for Merkel cell carcinoma (MCC) are not yet fully understood.

OBJECTIVES

To determine the effect of time to treatment initiation (TTI) on mortality in MCC and predictors of TTI itself.

METHODS

Retrospective cohort analysis of the National Cancer Database (NCDB) for cases of MCC from 2004-2016, excluding individuals with Stage IV MCC as surgery is not the preferred treatment for this group.

RESULTS

A total of 12,157 patients (average age:74.4 years, SD:10.9) were included in the study, 7,491(61.6%) were male and 4,666 (38.4%) were female. Risk of higher TTI was seen in Blacks (odds ratio [OR]:1.7, 95% CI:1.2,2.6) and elderly individuals over 70 years (OR:1.7, 95% CI:1.2,2.5). On Kaplan-Meier survival analysis, individuals with TTI <30 days had a significantly longer overall survival than those with TTI >120 days (6.1 vs. 4.8 years, p=0.0002). However, after controlling for clinical and tumor factors in Cox multivariable analysis, no difference in survival was noted for TTI <30 days and TTI >120 days (Hazard Ratio [HR]:0.9, 95% CI:0.8,1.1). Worse outcomes were also associated with increasing age (HR:2.0, 95% CI:1.7,2.5), male sex (HR:1.2, 95% CI:1.2-1.3), higher CDCC (HR:1.4, 95% CI:1.3,1.5), lack of radiation therapy (HR:0.8, 95% CI:0.8-0.9), lack of private insurance (HR:0.7, 95% CI:0.6-1.0), and surgical technique other than Mohs or WLE (HR:1.2, 95% CI:1.2-1.3).

CONCLUSIONS

Although TTI is a useful prognostic metric in isolated survival analysis, its utility declines when controlling for other factors. Age, radiotherapy, type of surgery performed, co-morbidities, tumor size, and lymph node involvement may be important predictors of survival.

Mohs Micrographic Surgery Versus Wide Local Excision in the Treatment of Merkel Cell Carcinoma: A Systematic Review

BACKGROUND

Merkel cell carcinoma (MCC) is an aggressive neoplasm with high rates of recurrences. Current guidelines recommend wide local excision (WLE) with 1 to 2 cm margins. However, Mohs micrographic surgery (MMS) offers a potential advantage over WLE because of its ability of sparing healthy tissue and assessing 100% of margins.

OBJECTIVE

To systematically evaluate the surgical modalities for the treatment of MCC.

MATERIALS AND METHODS

Eligible articles were identified using MEDLINE, Scopus, EMBASE, and Cochrane Library. All available studies investigating surgical treatment of MCC with WLE or MMS were considered.

RESULTS

Forty studies met the inclusion criteria. Thirty-one studies described patients treated with WLE, 3 with MMS, and 6 with either WLE or MMS. Subgroup analysis of Stage I MCC showed recurrence rates similar in both surgical modalities with local recurrence rate of 6.8% for WLE versus 8.5% for MMS (p = .64) and a regional recurrence rate of 15.2% for WLE versus 15.3% for MMS (p = .99).

CONCLUSION

Overall WLE cases were at a higher stage at presentation. Subgroup analysis showed that MMS is not inferior to WLE excision for the treatment of Stage I MCC and is a reasonable option for anatomic locations where tissue sparing is important.

Merkel Cell Carcinoma: An updated review of pathogenesis, diagnosis, and treatment options

Merkel cell carcinoma is a rare neuroendocrine carcinoma that typically appears in sun-exposed areas of the elderly. It has a poor prognosis and with its incidence projected to increase, it is vital for dermatologists to remain up to date with recent updates in this malignancy's pathogenesis and treatment. In the past few decades Merkel cell carcinoma's pathogenesis, more specifically its relation to the Merkel cell polyomavirus, has sparked further interest in the study of this carcinoma. Most cases are attributed to malignant transformation secondary to the Merkel cell polyomavirus, with a minority derived from DNA damage resulting from ultraviolet radiation. Investigators have also determined that there are immunologic influences in the development and prognosis of Merkel cell carcinoma, as individuals with HIV, solid organ transplants, and lymphoproliferative malignancies are at a greater risk of developing this carcinoma. Also, this immunologic link carries treatment value, as immunologic therapies are currently being investigated. This article provides a comprehensive review of the epidemiology and pathogenesis of Merkel cell carcinoma as well as the current treatments available and clinical trials underway. We also touch upon the updated National Comprehensive Cancer Network Clinical Practice Guidelines in Oncology in respect to its diagnosis and recommended treatment modalities.

Updates on the diagnosis, current and future therapeutic options in Merkel-cell carcinoma

Merkel-cell carcinoma (MCC) is a rare and extremely aggressive nonmelanocytic cutaneous neuroendocrine carcinoma. Historically, it has been associated with limited therapy options and poor prognosis. While its incidence has been rising over the last two decades, recent discoveries and a better understanding of its pathogenesis, viral association and immunologic features have allowed for the emergence of new therapies. Surgical excision with or without radiotherapy remains the first-line therapy for primary lesions without evidence of metastatic disease. The majority of MCC cases are regrettably diagnosed at advanced stages and oftentimes require systemic therapy. There have been several significant advances in the treatment of MCC in the last decade. Among these have been the development of immune checkpoint inhibitors targeting the programmed death protein-1 (PD-1)/programmed death ligand-1 (PDL-1). Despite recent success of immunotherapy, nearly 50% of patients diagnosed with MCC still succumb to the disease. Fortunately, there has been a number of new targeted therapies that hold great promise. Among them are phosphatidylinositide-3kinase (Pl3K) inhibitors, adoptive T-cell immunotherapy, activated NK-92 cells infusions and therapeutic vaccines. Additional emerging therapeutic targets include cellular ubiquitin-specific processing protease 7 (Usp7) that restricts viral replication and IFN genes (STING), activation of which promotes an antitumor inflammatory response.

Multimodal Strategy in Localized Merkel Cell Carcinoma: Where Are We and Where Are We Heading?

Merkel cell carcinoma (MCC) is an aggressive neuroendocrine tumor of the skin whose incidence is rising. Multimodal treatment is crucial in the non-metastatic, potentially curable setting. However, the optimal management of patients with non-metastatic MCC is still unclear. In addition, novel insights into tumor biology and newly developed treatments (e.g., immune checkpoint inhibitors) that dramatically improved outcomes in the advanced setting are being investigated in earlier stages with promising results. Nevertheless, the combination of new strategies with consolidated ones needs to be clarified. We reviewed available evidence supporting the current treatment recommendations of localized MCC with a focus on potentially ground-breaking future strategies. Advantages and disadvantages of the different treatment modalities, including surgery, radiotherapy, chemotherapy, and immunotherapy in the non-metastatic setting, are analyzed, as well as those of different treatment modalities (adjuvant as opposed to neoadjuvant). Lastly, we provide an outlook of remarkable ongoing studies and of promising agents and strategies in the treatment of patients with non-metastatic MCC.

Systematic literature review of current treatments for stage I-III Merkel cell carcinoma

Aim: There is a need to evaluate current treatments for stages I-III of Merkel cell carcinoma (MCC). Materials & methods: A systematic literature review was conducted to understand how patients with stage I-III MCC are treated and assess efficacy, safety, health-related quality of life and economic impact of current therapies. Embase was searched using the following inclusion criteria: publications from 2014 to 2019, in English, with adult patients (≥18 years) with early-stage MCC (i.e., stages I-III) and any interventions/comparators. Publications were excluded if they included only patients with stage IV MCC, had no distinction between early and advanced or metastatic MCC or had no extractable data. Results: A total of 18 retrospective studies were included. Few studies had evidence that surgery plus adjuvant radiotherapy significantly increased survival versus surgery alone in early MCC. Limited safety data were reported in three studies. None of the studies reported data on health-related quality of life or economic impact of treatment in patients with early-stage MCC. Conclusion: Although surgery plus adjuvant radiotherapy was a common treatment, no clear standard of care exists for stages I-III MCC and treatment outcomes need to be improved. All studies were retrospective with a high variability in sample sizes; hence, findings should be interpreted with caution.

Merkel Cell Carcinoma

Merkel cell carcinoma (MCC) is a rare and extremely aggressive neuroendocrine carcinoma of the skin, with increasing incidence worldwide. This review intends to propose a comprehensive evaluation of MCC epidemiology, clinical features, pathogenetic mechanisms, diagnosis, and therapies. A section is dedicated to immunological aspects and another to the involvement of angiogenesis and angiogenic growth factors in MCC progression, proposing novel diagnostic and therapeutic approaches. Advanced MCC tumors have been treated with immune checkpoint inhibitors with effective results. Therefore, the state of art of this immunotherapy is also examined, reporting on the most recent clinical trials in the field. We conclude by underlining the achievements in the understanding of MCC pathology and indicating the present needs for effective diagnosis and therapeutic management of the disease.

A SEER analysis of survival and prognostic factors in merkel cell carcinoma of the head and neck region

While Merkel cell carcinoma (MCC) of the head and neck is highly malignant, it remains poorly characterized due to its rarity. The purpose of this study was to examine prognostic factors for overall survival (OS) and disease-specific survival (DSS) in patients with MCC of the head and neck region. The Surveillance, Epidemiology and End Results registry was reviewed for patients diagnosed between 1984 and 2016 with histologically confirmed, primary MCC of the head and neck region. A total of 2818 patients met the inclusion criteria, with a median age at diagnosis of 77 years. At five and 10 years, respectively, the OS was 42.4% and 25.1% and the DSS was 67.9% and 64.1%. Multivariate Cox analysis indicated that predictors of decreased DSS included age at diagnosis ≥75 years, white race, increasing tumor spread, lymph node involvement and either the lip or the scalp/neck as a primary site. When adjusting for the aforementioned factors, tumor depth was not found to be a prognostic factor for DSS. We anticipate these results will help clinicians to counsel patients regarding expectations and potential prognosis.

Mohs surgery for early-stage Merkel cell carcinoma (MCC) achieves local control better than wide local excision ± radiation therapy with no increase in MCC-specific death

BACKGROUND

Merkel cell carcinoma (MCC) of the skin is most commonly treated with wide local excision (WLE) with or without adjuvant radiation therapy (RT). Mohs micrographic surgery (MMS) as monotherapy may offer an alternative treatment modality. The purpose of this study is to describe outcomes of patients with primary Stage I/II MCC treated with MMS alone and no RT.

METHODS

A retrospectively collected sample of 56 MCCs treated with MMS was studied over an 18-year period. Tumor and treatment characteristics were described, and follow-up was assessed.

RESULTS

A total of 56 primary Stage I/II MCCs in 53 patients were treated with MMS as monotherapy from April 2001 through July 2019. Patients were followed for an average of 4.6 years (median 2.7 years, range 0.8 to 16.9 years), of which 19 (33.9%) had follow-up of 5 years or more. There were no local recurrences due to inadequate excision. The 5-year Kaplan-Meier MCC-specific survival for AJCC8 Stage I and AJCC8 Stage IIA were 91.2% and 68.6%, respectively.

CONCLUSION

In comparison to historical controls, Mohs surgery offers a survival that is at least as good as WLE +/- RT, with the added benefits of no need for adjuvant RT or the need for further surgery for treatment of local recurrence.

Surgical Management of Merkel Cell Carcinoma

The incidence of Merkel cell carcinoma (MCC) continues to increase. Understanding of MCC biology has advanced rapidly, with current staging providing valuable prognostic information. MCC treatment often is multidisciplinary. Surgery remains an important component in the staging and treatment, most commonly involving wide excision of the cancer and sentinel lymph node biopsy. Lymphadenectomy is used to treat nodal disease. Radiotherapy enhances locoregional control and possibly survival. Systemic therapies, in particular novel immunotherapies, may be promising in the treatment of advanced or recurrent and metastatic disease.

Merkel Cell Carcinoma: A Description of 11 Cases

Merkel cell carcinoma (MCC) is a malignant neuroendocrine tumor. Metastasis or lymph node spread is often detected at diagnosis. We performed a descriptive, retrospective study of patients diagnosed with MMC at Hospital Universitario Fundación Alcorcón in the Community of Madrid, Spain between January 1998 and December 2018. Eleven patients (7 men [63%] and 4 women [36%]; mean age, 77.6 years) were diagnosed with MCC during this 21-year period; 45% of patients had stage IIIB disease (pTNM) at diagnosis. All patients but one underwent local surgery, and lymphovascular invasion was detected in 7 cases. Eight patients received adjuvant therapy after surgery (radiation therapy in 5 cases and chemotherapy in 3). Six patients (54%) died of MCC (mean survival, 14.5 months). MCC is an uncommon malignant tumor with an annual incidence of around 0.18 to 0.41 cases per 100 000 inhabitants; this is similar to the rate of 0.29 to 0.32 cases per 100 000 inhabitants a year detected in our series. Results with avelumab, a drug recently approved for the treatment of metastatic MCC; have been promising.

New perspectives in Merkel cell carcinoma

PURPOSE OF REVIEW

Merkel cell carcinoma (MCC), a rapidly progressing skin cancer, has poor prognosis. We reviewed the epidemiology, pathogenesis, diagnosis and treatment of MCC, with a focus on recent therapeutic advancements.

RECENT FINDINGS

Risk factors for MCC, such as old age, immunosuppression, polyomavirus infection and exposure to UV radiation have already been identified, but the underlying mechanisms leading to carcinogenesis still need clarification. On the basis of recent advances, immunotherapy - in particular, inhibition targeting the programmed cell death protein 1/programmed death-ligand 1 (PD1)/PDL1) immune checkpoint blockade - is currently being investigated in the treatment of metastatic MCC. Avelumab, an anti-PDL1 antibody, was the first drug to be approved internationally as second-line monotherapy for patients with advanced MCC, based on results from the JAVELIN Merkel 200 clinical trial. Avelumab has also recently been approved as first-line treatment for advanced MCC in Europe. Pembrolizumab (anti-PD1) in first-line and nivolumab (anti-PD1) in first-line and second-line treatments are two other checkpoint inhibitors that are under investigation, and showing promising results. New innovative therapies are also in development.

SUMMARY

New insights concerning advances in MCC diagnosis and treatment have been highlighted. Immunotherapy for metastatic MCC constitutes a recent breakthrough in an unmet medical need, but alternative therapies should continue to be investigated.

INSM1 Is More Sensitive and Interpretable than Conventional Immunohistochemical Stains Used to Diagnose Merkel Cell Carcinoma

Merkel cell carcinoma (MCC) is an extremely aggressive skin cancer that must be distinguished from other basaloid cutaneous neoplasms that have different treatments and prognoses. This is sometimes challenging in small shave specimens, crushed samples, lymph nodes, and core needle biopsies. Insulinoma-associated protein 1 (INSM1) immunohistochemistry is a sensitive nuclear marker of neuroendocrine differentiation. INSM1 staining was performed on 56 MCC (47 primary tumors, 9 nodal metastases), 50 skin control cases that included basal cell carcinomas, basaloid squamous cell carcinomas, Bowen disease, sebaceous neoplasms, melanoma, and B-cell lymphomas, and 28 lymph node control cases that included metastatic neuroendocrine neoplasms, melanomas, squamous cell carcinomas, lymphomas, and adenocarcinomas. Percent of staining nuclei (0, <25%, 25% to 50%, 50% to 75%, >75%) and intensity (weak, moderate, strong) were recorded for each sample. All 56 MCC expressed INSM1. By comparison, synaptophysin, CK20, and chromogranin were expressed in 96%, 92%, and 32% of MCC, respectively. While the 3 conventional markers showed significant variability in staining intensity and distribution, INSM1 stained >75% tumor nuclei in 89% of MCC and 50% to 75% of tumor nuclei in 11%. Staining intensity was strong in 85% and moderate in 15%. None of the 50 cutaneous basaloid non-MCC neoplasms in the control group stained with INSM1, and among the lymph node controls 5 of 5 neuroendocrine neoplasms expressed INSM1, confirming that INSM1 staining cannot distinguish MCC from metastatic extracutaneous neuroendocrine carcinoma. INSM1 holds promise as a neuroendocrine marker that can distinguish MCC from its mimickers in the skin and improve detection of sentinel lymph node metastases.

Merkel Cell Carcinoma: Updates on Staging and Management

Merkel cell carcinoma is an aggressive neuroendocrine carcinoma with increasing incidence over the past few decades. The TNM Staging System used for Merkel cell carcinoma was updated by the American Joint Committee on Cancer in 2017. Clinical practice guidelines were updated by the National Comprehensive Cancer Network on August 31, 2018. This article reviews the most recent evidence-based updates on staging and management.

Human oncoviruses: Mucocutaneous manifestations, pathogenesis, therapeutics, and prevention: Papillomaviruses and Merkel cell polyomavirus

In 1964, the first human oncovirus, Epstein-Barr virus, was identified in Burkitt lymphoma cells. Since then, 6 other human oncoviruses have been identified: human papillomavirus, Merkel cell polyomavirus, hepatitis B and C viruses, human T-cell lymphotropic virus-1, and human herpesvirus-8. These viruses are causally linked to 12% of all cancers, many of which have mucocutaneous manifestations. In addition, oncoviruses are associated with multiple benign mucocutaneous diseases. Research regarding the pathogenic mechanisms of oncoviruses and virus-specific treatment and prevention is rapidly evolving. Preventative vaccines for human papillomavirus and hepatitis B virus are already available. This review discusses the mucocutaneous manifestations, pathogenesis, diagnosis, treatment, and prevention of oncovirus-related diseases. The first article in this continuing medical education series focuses on diseases associated with human papillomavirus and Merkel cell polyomavirus, while the second article in the series focuses on diseases associated with hepatitis B and C viruses, human T-cell lymphotropic virus-1, human herpesvirus-8, and Epstein-Barr virus.