The impact of preradiation residual disease volume on time to locoregional failure in cutaneous Merkel cell carcinoma--a TROG substudy

Immune activity in Merkel cell carcinoma

Merkel cell carcinoma (MCC) is widely known as a highly malignant skin cancer. The pathogenesis of MCC, however, remains mysterious due to the extremely small number of cases and its prevalence in the elderly. Despite its high‐grade malignancy, spontaneous regression occurs with some frequency. The immune activity of the tumor underlies this peculiar behavior. In recent years, immune checkpoint blockade therapies, including the anti‐programmed death ligand 1 antibody, have provided successful results. These therapies, however, are ineffective in approximately half the patients with advanced MCC and few treatments are available for those patients. In this review, we summarize the increasing body of evidence relating to the immune activity of MCC and immunological biomarkers. The interesting and sometimes peculiar behavior of MCC, such as their spontaneous regression, is largely due to their high immunosensitivity. Understanding the tumor immunokinetics of MCC should provide critical insight for understanding cancer immunotherapy. Here, we introduce a new classification for MCC according to its immune activity. Combined application of programmed death ligand 1 (a prognostic factor and predictor of the efficacy of immune checkpoint inhibitors in various cancers) with glucose‐6‐phosphate dehydrogenase (a new promising biomarker for MCC) may enable classification of MCC based on its immune status. Whether the new classification can be used to predict the efficacy of immune checkpoint blockade therapies remains to be evaluated in future studies, but the classification may facilitate future treatment selection.

Viruses and Skin Cancer

Advances in virology and skin cancer over recent decades have produced achievements that have been recognized not only in the field of dermatology, but also in other areas of medicine. They have modified the therapeutic and preventive solutions that can be offered to some patients and represent a significant step forward in our knowledge of the biology of skin cancer. In this paper, we review the viral agents responsible for different types of skin cancer, especially for solid skin tumors. We focus on human papillomavirus and squamous cell cancers, Merkel cell polyomavirus and Merkel cell carcinoma, and human herpesvirus 8 and Kaposi’s sarcoma.

Sex Differences in Overall Survival and the Effect of Radiotherapy in Merkel Cell Carcinoma-A Retrospective Analysis of a Swedish Cohort

Simple Summary

Merkel cell carcinoma (MCC) is a rare and aggressive skin cancer which is believed to be partially caused by a virus or ultraviolet exposure. Most previous studies have shown that MCC is more common in men compared to women, virus associated MCC has a better prognosis and surgery followed by radiotherapy gives a better outcome. In this article, we explore these traits in a Swedish cohort of 113 patients and find that MCC is more common in women and female patients have a longer survival compared to male patients. In addition, we found that virus negative MCC has a worse outcome in male patients and radiotherapy after surgery gives a better outcome for patients who are treated with a curative dosage, irrespective of sex.

Abstract

Merkel cell carcinoma (MCC) is a rare and aggressive skin cancer where Merkel cell Polyomavirus (MCPyV) contributes to the pathogenesis. In an adjuvant setting, radiotherapy (RT) is believed to give a survival benefit. The prognostic impact of sex related to MCPyV-status and adjuvant RT were analyzed in patients referred to Karolinska University Hospital. Data were collected from 113 patients’ hospital records and MCPyV analyses were made in 54 patients (48%). We found a significantly better overall survival (OS) for women compared to men and a significant difference in OS in patients receiving adjuvant RT. Furthermore, we found that men with virus negative MCC have an increased risk for earlier death (HR 3.6). This indicates that MCPyV positive and negative MCC act as two different diseases, and it might be due to different mechanism in the immune response between male and female patients. This could have significance in tailoring treatment and follow-up in MCC patients in the future.

Management Recommendations for Merkel Cell Carcinoma-A Danish Perspective

Merkel cell carcinoma (MCC) is a rare malignant neuroendocrine carcinoma of the skin with a poor prognosis and an apparent increase in incidence. Due to its rarity, evidence-based guidelines are limited, and there is a lack of awareness among clinicians. This review constitutes the consensus management recommendations developed by the Danish MCC expert group and is based on a systematic literature search. Patients with localized disease are recommended surgical excision and adjuvant radiotherapy to the primary site; however, this may be omitted in patients with MCC with low risk features. Patients with regional lymph node involvement are recommended complete lymph node removal and adjuvant radiotherapy in case of extracapsular disease. Metastatic disease was traditionally treated with chemotherapy, however, recent clinical trials with immune therapy have been promising. Immune checkpoint inhibitors targeting the programmed cell death protein 1(PD-1)/programmed death-ligand 1(PD-L1) axis should therefore be strongly considered as first-line treatment for fit patients. A 5-year follow-up period is recommended involving clinical exam every 3 months for 2 years and every 6 months for the following 3 years and PET-CT one to two times a year or if clinically indicated. These national recommendations are intended to offer uniform patient treatment and hopefully improve prognosis.

Management of regional metastatic disease in cutaneous malignancy of the head and neck. 3. Merkel cell carcinoma

This is the third of three articles that give an overview of the current evidence for management of the neck and parotid in patients with cutaneous cancers of the head and neck. In this paper we discuss Merkel cell carcinoma (MCC) and review the latest evidence for management of the regional nodes.

S2k guidelines for Merkel cell carcinoma (MCC, neuroendocrine carcinoma of the skin) - update 2018

Merkel cell carcinoma (MCC, ICD-O M8247 / 3) is a rare malignant primary skin tumor with epithelial and neuroendocrine differentiation. The neoplastic cells share many morphological, immunohistochemical and ultrastructural characteristics with Merkel cells of the skin. The diagnosis of MCC is rarely made on clinical grounds. Histological and immunohistochemical studies are usually required to confirm the clinical suspicion. Given the frequent occurrence of occult lymph node metastasis, sentinel lymph node biopsy should be performed once distant metastasis has been ruled out by cross-sectional imaging. Primary tumors without evidence of organ metastases are treated with complete surgical excision with appropriate surgical margins. Radiation therapy should be considered at all stages of the disease. For advanced MCC that is no longer amenable to curative treatment by surgery or radiation therapy, there is currently no established systemic therapy for which an improvement in recurrence-free survival or overall survival has been demonstrated in a prospective randomized trial. However, immunotherapy using PD-1/PD-L1 blockade seems to be superior to chemotherapy. Various factors warrant that further diagnostic and therapeutic interventions be determined by an interdisciplinary tumor board. These factors include the tumor's aggressiveness, the frequent indication for sentinel lymph node biopsy along with the frequent occurrence in the head and neck region, the potential indication for adjuvant radiation therapy as well as the complexity of the required diagnostic workup.

Merkel cell carcinoma: An update and review: Current and future therapy

Merkel cell carcinoma (MCC) is a rare neuroendocrine tumor of the skin associated with a high risk of local recurrence and distant metastases. It most commonly occurs on sun-exposed areas of white patients >65 years of age. The Merkel cell polyomavirus (MCV) is thought to be responsible for malignant transformation in approximately 80% of cases in the northern hemisphere, while ultraviolet radiation-induced DNA damage is implicated in MCV-negative tumors. The overall incidence of MCC is low, with approximately 1600 cases diagnosed annually in the United States. The rate is much higher in patients with lymphoproliferative malignancies, solid organ transplants, and HIV infection. The low overall incidence of this tumor makes it challenging to conduct prospective clinical trials with sufficient power. As a result, most management recommendations are based on case series, retrospective reviews, and expert opinion. The pathogenesis, diagnosis, and staging of MCC was discussed in the first article in this continuing medical education series. This article focuses on current management guidelines and promising new therapies in development. Because of the complexity, aggressive nature, and individuality of each case, MCC is best treated by a multidisciplinary team.

Identifying an Optimal Adjuvant Radiotherapy Dose for Extremity and Trunk Merkel Cell Carcinoma Following Resection: An Analysis of the National Cancer Database

Importance

Merkel cell carcinoma (MCC) is a rare and aggressive cutaneous neuroendocrine neoplasm with a high risk of recurrence following resection. Despite a rising incidence over the past 3 decades, there is a paucity of prospective data owing to the rarity of this disease.

Objective

To determine the optimal adjuvant radiation therapy (RT) dose following resection of localized MCC of the extremities or trunk.

Design, Setting, and Participants

Using the National Cancer Database, a large national database consisting of a heterogeneous population and treatment settings, we retrospectively analyzed a cohort of 2093 patients 18 years or older with stage I to III MCC of the extremities and/or trunk treated with definitive surgery and adjuvant RT between 1998 and 2011. Exclusion criteria included receiving treatment with palliative intent, preoperative RT, non-external-beam RT, and radiation dose of 30 Gy or lower or 70 Gy or higher. Cox proportional hazards regression model was used to compare overall survival (OS) between RT dose groups, accounting for age, sex, race, stage, surgery type, margin status, comorbidities, and use of chemotherapy.

Exposures

Radiation therapy dose was categorized into 4 groups: group 1 received the lowest dose (>30 to <40 Gy); group 2, the next lowest (40 to <50 Gy); group 3, the second highest dose (50 to 55 Gy); and group 4, the highest dose (>55 to 70 Gy).

Main Outcome and Measure

Overall survival.

Results

Data from 2093 patients were analyzed; there were 1293 men (61.8%) and 800 women (38.2%) (median age, 73 years). After a median follow-up of 37 months for the entire cohort, 904 deaths were reported. The 3-year OS rates for groups 1, 2, 3, and 4 were 41.8%, 69%, 69.2%, and 66%, respectively (omnibus P < .001). Compared with group 3 (50 to 55 Gy), equivalent OS was seen in group 2 (40 to <50 Gy; adjusted hazard ratio [AHR], 0.89; 95% CI, 0.63-1.27; P = .52) and group 4 (>55 to 70 Gy; AHR, 1.18; 95% CI, 0.93-1.48; P = .17), but worse OS was found in group 1 (>30 to <40 Gy; AHR, 2.63; 95% CI, 1.44-4.80; P < .001).

Conclusions and Relevance

Adjuvant RT dose from 40 to lower than 50 Gy appears adequate for extremities and/or trunk stage I to III MCC, with OS equivalent to that found at higher-dose regimens (>50 to 70 Gy).

Merkel Cell Carcinoma of the Head and Neck: Recommendations for Diagnostics and Treatment

Background

Merkel cell carcinoma (MCC) is a rare, aggressive tumor that often occurs in the head and neck region. Because of these features, the classifications and diagnostic and treatment regimens are frequently modified. Especially in the anatomically complex head and neck region, it is crucial to be aware of the current recommendations for diagnostics and treatment of MCC to ensure appropriate treatment. This overview aims to summarize the currently available literature.

Methods

The authors reviewed the relevant literature and international guidelines for MCC from 2012 to 2017 with respect to epidemiology and prognosis, diagnostic procedures and imaging, surgery, radiation, systemic treatment, and aftercare. These results were compared with existing guidelines, some of them current, and recommendations were derived.

Results

Marked developments in imaging have resulted in an increased use of functional imaging. The surgical concepts have changed regarding safety margins and the use of sentinel node biopsies. In systemic treatment, a move from conventional agents toward immuno-oncology can be observed.

Conclusions

For staging, it is important to be as exact as possible using functional imaging (e.g., positron emission tomography/computed tomography scan), especially in the head and neck area with its complex lymph drainage. This often plays an especially important role in early stages of the tumor, when the resection margin can be reduced to preserve the organ. Aftercare also should include functional imaging. In an advanced, metastatic stage, immuno-oncology (PD-1, PD-L1, CTLA-4) is superior to the previous methods of systemic treatment.

Merkel cell carcinoma: emerging biology, current approaches, and future directions

Merkel cell carcinoma (MCC) is an aggressive neuroendocrine cutaneous cancer that predominantly occurs in patients who are older, and is associated with a high rate of distant failure and mortality. Current management strategies that incorporate surgery and radiotherapy achieve high rates of locoregional control, but distant failure rates remain problematic, highlighting the need for new effective systemic therapies. Chemotherapy can achieve high response rates of limited duration in the metastatic setting, but its role in definitive management remains unproven. Recent developments in our knowledge about the biology of MCC have led to the identification of new potential therapeutic targets and treatments. A key finding has been the discovery that a human polyomavirus may be a causative agent. However, emerging data suggests that MCC may actually be two distinct entities, viral-associated and viral-negative MCC, which is likely to have implications for the management of MCC in the future and for the development of new treatments. In this review, we discuss recent discoveries about the biology of MCC, current approaches to management, and new therapeutic strategies that are being investigated.

Merkel cell carcinoma: Do you know your guidelines?

BACKGROUND

Merkel cell carcinoma (MCC) is a cutaneous neuroendocrine malignancy that exhibits clinically aggressive features and is associated with a poor prognosis. The incidence of MCC seems to be increasing for reasons unknown, and is estimated to be 0.32/100,000 in the United States.

METHODS

This article will review the current literature and National Comprehensive Cancer Network practice guidelines in the treatment of MCC.

RESULTS

Resection of MCC with negative margins remains the mainstay of therapy. Positive nodal disease should be treated with neck dissection and adjuvant radiotherapy. High-risk patients should undergo adjuvant radiotherapy, which improves oncologic outcomes. The role of chemotherapy is less clear and is currently reserved for advanced-stage MCC and palliative therapy.

CONCLUSION

The pathogenesis of MCC has recently been impacted with the discovery of the Merkel cell polyomavirus (MCPyV). Research to establish targeted and immunologic therapeutic options are ongoing.

Chemotherapy compliance in high-risk Merkel cell carcinoma treated with chemoradiotherapy

OBJECTIVE

To evaluate chemotherapy (CT) compliance in patients treated with chemoradiotherapy (CRT) for high-risk Merkel cell cancer (MCC).

METHODS

Data from three prospective clinical trials in high-risk MCC performed by the Trans-Tasman Radiation Oncology Group were included in this analysis. Patients were treated with one of two carboplatin-based CT schedules and standardised radiotherapy (RT) to the primary site and nodes to a dose of 50-60 Gy in 25-30 fractions. Patients' baseline characteristics were analysed using χ² tests to determine compliance factors for completing CT. A Cox univariate analysis was performed to assess the impact of CT compliance on time to locoregional failure, time-to-distant failure, time-to-recurrence and time-to-death.

RESULTS

A total of 88 patients were identified, with a median follow up of 38.5 months. Of these, 75 (85%) completed CT (median age 64.2 years, range 62.0-66.4), while 13 did not (median age 72 years, range 68.1-75.9), P = 0.006. Women comprised 18/75 patients who completed CT and 7/13 patients who did not complete it (P = 0.03). Performance status, site, stage, surgical margins, RT dose and toxicity did not impact on their CT compliance. At 5 years, 26% of patients had locoregional relapse, 26% had distant failure and 34% had died.

CONCLUSIONS

In this small cohort of patients treated with CRT for high-risk MCC, older age and female sex were associated with failure to complete CT. Severe acute skin and haematological toxicity did not correlate with failure to complete CT.

Nonmelanoma Cutaneous Head and Neck Cancer and Merkel Cell Carcinoma: Current Concepts, Advances, and Controversies

Nonmelanoma skin cancer (NMSC) is the most common cancer worldwide and the most frequently observed malignancy in whites. Approximately 75% to 80% are basal cell carcinomas and 20% to 25% are squamous cell carcinomas. Incidence is increasing, partly reflecting an ageing population, and NMSC is more commonly seen in men. The predominant causative agent is ultraviolet solar radiation exposure, with the majority of cases occurring on the head and neck. Surgical excision is typically the treatment of choice, providing histopathologic information, high cure rates, and acceptable cosmetic and functional outcomes. Radiation therapy is reserved for cases where surgery is not the preferred choice or for high-risk cases where adjuvant therapy is recommended. Although overall mortality rates are low, patients with complex cases such as those with immunosuppression should be considered for management within multidisciplinary tumor boards. In contrast, Merkel cell carcinoma is a rare and aggressive malignancy, frequently arising on the head and neck in older whites, with a poorer prognosis. This article focuses on the current evidence guiding practice, recent advances, and areas of controversy in NMSC and Merkel cell carcinoma of the head and neck.

Radiotherapy alone in patients with Merkel cell carcinoma: the Westmead Hospital experience of 41 patients

OBJECTIVES

To review the role of radiotherapy as treatment (RTx) alone in patients with Merkel cell carcinoma (MCC).

METHODS

Data on 41 patients with MCC treated with RTx alone between 1993 and 2013 at Westmead Hospital, Sydney, were reviewed and analysed.

RESULTS

The patients' median age was 80 (range 45-96 years) among 18 (44%) women and 23 (56%) men. All but one patient were white and six (15%) were immunosuppressed. Most (59%) were irradiated at initial diagnosis with the remainder treated in the relapse setting. The median duration of follow up was 39 months. Head and neck was the most frequently treated site (63%). The median lesion size was 30 mm (range 5-130 mm). The in-field control rate was 85%. Most out-of-field relapses were to visceral organs. Overall survival at 5 years was 40%.

CONCLUSIONS

Patients with MCC treated with RTx alone experience a high likelihood of obtaining in-field disease control. Doses of 50-55 Gy in 20-25 fractions are recommended but lower doses (25 Gy in five fractions) are still effective. A minority will be cured with many patients subsequently dying of systemic relapse.