Merkel cell tumour: Clinical behaviour and treatment

Abstract

We have reviewed 30 reports of Merkel cell tumour and described a further five cases in order to establish a database and from this more clearly define the biology of this tumour, prognostic factors that govern outcome, and optimal management. After excision alone of the primary lesion, local recurrence occurred in 39 per cent of patients and regional failure occurred in 46 per cent. In contrast, in patients treated by excision plus prophylactic treatment (adjuvant node dissection and/or adjuvant radiation), local recurrence occurred in 26 per cent and regional failure in 22 per cent. Locoregional recurrence carried an ominous significance with 67 per cent of patients subsequently dying of the disease. For patients who either presented with regional disease or later developed regional disease, the best outcome (44 per cent survival with mean follow-up of 40 months) was obtained following treatment by therapeutic node dissection with or without radiation. In contrast, treatment of regional disease with radiation alone was associated with only a 20 per cent survival rate. Unfavourable prognostic factors included young age, lesions sited in the head and neck or trunk, male sex, and the presence of locoregional failure and/or systemic disease. We conclude that Merkel cell tumours behave in a similar manner to the aggressive variants of melanoma and that minimal treatment consists of wide surgical resection of the primary lesion (with a margin of 2.5-3 cm) coupled with resection and probably also radiation of regional disease if present. In addition, consideration should be given to prophylactic node dissection in node negative patients, especially in those patients with unfavourable prognostic factors.

High-Risk Merkel Cell Carcinoma of the Skin Treated With Synchronous Carboplatin/Etoposide and Radiation: A Trans-Tasman Radiation Oncology Group Study—TROG 96:07

“…[3][4][5][6][7] Thirty-three patients (62%) registered on this study had involved nodes (stage II) at presentation. This contrasts with the literature where the reported incidence of nodes at presentation varied from 9% to 33%, [3][4][5][8][9][10][11] and confirms the particularly poor prognostic profile of patients in this trial (being at high risk of disseminated disease).…”

“…Prognostic factors have been well described in previous reports [3][4][5][6][7][8][9][10][11][12] and a recent review by Goessling et al 13 summarizes these. In comparing these results with those reported in the literature, it is important to match the proportion of patients with adverse prognostic variables, the most important being the presence of nodal metastases.…”

Clinical added-value of 18FDG PET in neuroendocrine-merkel cell carcinoma

“…The etiology of this malignancy is still unknown. Documented cases have reported MCC after radiation and immunosuppressive therapies, or in association with other cancers (7).…”

Expression and prognostic significance of matrix metalloproteinases and their tissue inhibitors in primary neuroendocrine carcinoma of the skin

“…However, cumulative data from small series have suggested that stage, size of the primary tumor, and gender may have an influence on survival, whereas the prognostic impact of anatomic location and age are more controversial. [5][6][7][8] Although various factors can determine the aggressiveness of PNCs, the capacity for invasion and metastasis of tumor cells, involving the degradation of components of basement membranes and the extracellular matrix, is certainly important. The matrix metalloproteinases (MMPs) are a large family of zinc-dependent proteolytic enzymes 9,10 involved in the degradation of different components of the extracellular matrix.…”