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

Abstract

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.

A review on the oncogenesis of Merkel cell carcinoma: Several subsets arise from different stages of differentiation of stem cell

“…[35] Merkel cells located within the basal cell layer of the epidermis are slow-acting mechanoreceptors because they are in contact with unmyelinated nerve fibers. [2,38] Two theories have been proposed regarding the origin of Merkel cells. One possibility is that Merkel cells result from neural crest-derived cells of the amine precursor uptake and decarboxylation system, [39] whereas others consider that it originated from embryonic epidermal stem cells.…”

“…Merkel cell carcinoma (MCC), a rare primary cutaneous neuroendocrine neoplasm, is extremely aggressive and has a higher mortality rate than melanoma. [ 1 , 2 ] In the United States, the annual incidence of MCC was 0.7/100,000 persons in 2013, and there has been an exponential global increase over the past 30 years. [ 3 , 4 ] Risk factors for developing MCC include chronic ultraviolet (UV) exposure, immunosuppression, skin fires, and older age.…”

Epidemiology of Merkel Cell Polyomavirus Infection and Merkel Cell Carcinoma

“…Early diagnosis and associated smaller tumor diameter and lower tumor stages are critical for the prognosis of MCC [ 47 , 48 ]. The latest developments in the diagnosis and treatment of MCC have been reviewed recently in this and other journals [ 49 , 50 , 51 , 52 , 53 , 54 ].…”

“…MCC appears as pink to reddish-livid and sometimes skin-colored, often fast-growing, and painless, shiny nodules or plaques. The main features are described by the acronym AEIOU: asymptomatic, (rapidly) expanding nodules, immunosuppressed, older than 50 years, and UV radiation exposure [ 50 ]. ( a ) Merkel cell carcinoma above the right eye covering the eyebrow.…”

Knockdown of nicotinamide N-methyltransferase suppresses proliferation, migration, and chemoresistance of Merkel cell carcinoma cells in vitro

“…MCC is recognized as a chemosensitive malignancy displaying high response rates; thus, chemotherapy is used for the primary therapy of advanced MCC or as an adjuvant treatment. Nonetheless, the duration of response to chemotherapy is poor, with patients suffering from significant toxicity to the therapy [ 5 ]. Therefore, it is of outmost importance the identification of new diagnostic and prognostic markers, as well as biomolecules that could be used as target for precision medicine.…”