Adjuvant locoregional radiotherapy as best practice in patients with Merkel cell carcinoma of the head and neck.

BACKGROUND Australians have the highest rate of skin cancer in the world. Merkel cell carcinoma (MCC) is the most aggressive skin cancer reported, with a high propensity for relapse. The purpose of this study was to report the patterns of recurrence after initial treatment, the outcomes, and any predictors for survival. METHODS We identified 37 patients who were diagnosed with MCC of the head and neck between 1980 and 2002. In this retrospective analysis, multivariate analysis was performed by use of Cox regression analysis. Disease-free survival (DFS) and overall survival (OS) were calculated with Kaplan-Meier survival curves. RESULTS The median age at diagnosis was 75 years (range, 46-89 years), with 24 men and 13 women. The median duration of follow-up was 26 months (range, 7-104 months). Twenty-nine patients (78%) initially were seen with a primary lesion, and eight (22%) had a primary lesion and clinical nodal disease. A total of 24 (65%) of 37 patients had a relapse, with regional relapse the most common site of the first relapse (12 of 37). The rates of local relapse were similar for patients undergoing local surgery (three of 17; 18%) or surgery and adjuvant radiotherapy (two of 19; 11%). Nodal relapse developed in seven (50%) of 14 patients not receiving regional treatment compared with six (26%) of 23 patients receiving regional treatment of some type. Patients treated with surgery and adjuvant radiotherapy experienced a significantly longer median DFS than did those undergoing surgery alone (23 months vs 6 months; p < .01). The 3-year OS and DFS rates for the entire study population were 66% and 25%, respectively. CONCLUSION MCC is an aggressive skin cancer. There is a sufficient body of evidence, including this study, to consider the addition of adjuvant locoregional radiotherapy as best practice in markedly improving freedom from relapse.