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

Abstract

BackgroundMerkel 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.MethodsThe 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.ResultsMarked 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.ConclusionsFor 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.

Prognostic Factors in Merkel Cell Carcinoma: A Retrospective Single-Center Study in 90 Patients

“…Merkel Cell Carcinoma (MCC) is a rare neuroendocrine neoplasm of the skin [ 1 ]. It was first described by Toker in 1972 as trabecular carcinoma of the skin [ 2 ] and then renamed in its current form because of common features with Merkel cells [ 3 ]. Consequently, Merkel cells were suggested to be the source of MCC, on the basis of both the ultrastructural finding of neuroendocrine granules and the immunohistochemical expression of CK20 ( Figure 1 ) and CD56 [ 4 , 5 , 6 ].…”

Evidence and Considerations on Treatment of Small Size Merkel Cell Head and Neck Carcinoma

“…5,11 Postoperative radiation therapy for clinical N0 neck dissection or negative SLNB is disputed in the literature, especially for MCC localized in the head and neck. 11,18 In the most recently published NCCN Guidelines for MCC 9 , PORT (50-56 Gy) on the primary tumor side is recommended even with negative resection margins, but observation is considered an option when the primary tumor is small, widely excised, and without other risk factors, such as lymphovascular invasion or immune suppression. Postoperative radiation therapy on the draining nodal basin is not indicated after negative SLNBs, but is always indicated after neck dissection with multiple involved nodes.…”

Nodal Merkel Cell Carcinoma in Head and Neck Lesions with an Unknown Primary: A Case Report in Light of the Literature

“…Patients with nodal MCC have a better prognosis than those with metastatic nodal MCC and a concurrent primary tumor. [15][16][17][18][19] Surgical excision of the primary lesion and additional chemotherapy remain central in the treatment of nodal MCC with primary unknown. In recurrent cases, chemotherapy and radiotherapy have been standard treatment modalities.…”

“…In recurrent cases, chemotherapy and radiotherapy have been standard treatment modalities. 18,19 A different regimen from initial treatment was selected from consideration of drug sensitivity in our case. However, recent reports demonstrated that PD-1 and PD-L1 inhibitors have been shown to be superior to other systemic treatments for MCC in advanced stages.…”