Further insights into the natural history and management of primary cutaneous neuroendocrine (Merkel cell) carcinoma.
OBJECTIVE
Primary cutaneous neuroendocrine (Merkel cell) carcinoma is a rare neoplasm with aggressive behavior but potential for response to radiotherapy and chemotherapy. Optimal treatment regimens are evolving based on reports of case series and a growing understanding of the natural history.


METHODS
A retrospective analysis of 34 cases treated at two Australian Institutions over 13 years is presented, focusing on clinical features and response to therapy.


RESULTS
The aggressive nature of this neoplasm is confirmed by the local recurrence rate of 22% following surgical excision, the development of regional node metastases in 76%, and of distant metastases in 70%. Overall median survival was 24 months with 65% of patients succumbing to metastatic disease. An association with B cell malignancies and immunosuppressive therapy is noted, with these patients having a poorer outcome, and one spontaneous remission was observed. Radiation therapy produced responses in 21 of 30 measurable sites (11 complete, 10 partial), and in 11 sites irradiated prophylactically there was only one infield relapse (9%). Responses to chemotherapy were observed in 8 of 20 applications (40%), particularly carboplatin and etoposide given in the setting of regional node disease.


CONCLUSIONS
In this poor prognosis tumor, further investigation of adjuvant radiotherapy and chemotherapy is warranted, as responsiveness of recurrent disease is confirmed. Immunological factors appear important in the natural history, and their manipulation may offer additional therapeutic options.
Department of Clinical Oncology, Royal North Shore Hospital, Sydney.
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Boyle
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Pendlebury
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Bell
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001315:Australia; D016190:Carboplatin / Q000627:therapeutic use; D015266:Carcinoma, Merkel Cell / Q000188:drug therapy / Q000401:mortality / Q000473:pathology* / Q000532:radiotherapy*; D017024:Chemotherapy, Adjuvant; D005047:Etoposide / Q000627:therapeutic use; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D011879:Radiotherapy Dosage; D018714:Radiotherapy, Adjuvant; D012189:Retrospective Studies; D012878:Skin Neoplasms / Q000188:drug therapy / Q000401:mortality / Q000473:pathology* / Q000532:radiotherapy*; D015996:Survival Rate; D013997:Time Factors
D000970:Antineoplastic Agents; D005047:Etoposide; D016190:Carboplatin