Resection Margins in Merkel Cell Carcinoma: Is a 1-cm Margin Wide Enough?

BACKGROUND: Guidelines regarding specific resection margins for primary Merkel cell carcinoma (MCC) are not well established. The current National Comprehensive Cancer Network (NCCN) guidelines recommend 1- to 2-cm resection margins. This study aimed to determine the impact of margin width on local recurrence (LR), disease-specific survival (DSS), overall survival (OS), and type of wound closure. METHODS: All patients who underwent resection of primary MCC at a single institution from 2000 to 2015 were reviewed. Patient demographics, clinicopathologic characteristics, treatments, and outcomes were reviewed. RESULTS: A total of 240 patients underwent resection of primary MCC with resection margin width identified in the operative report. The median age was 76 years, and 65.8% of the patients were men. Of the 240 patients, 85 (35.4%) had head and neck primaries, 140 (58.3%) had extremity primaries, and 15 (6.3%) had trunk primaries. In terms of margins, 69 patients (28.8%) had a margin of 1 cm, 36 patients (15%) had a margin of 1.1-1.9 cm, and 135 patients (56.2%) had a margin of 2 cm or more. The median follow-up period was 21 months. The LR rate was 2.9% for a margin of 1 cm, 2.8% for a margin of 1.1-1.9 cm, and 5.2% for a margin of 2 cm or more (p = 0.80). The 5-year OS was 63.6% for a margin of 1 cm, 59.7% for a margin of 1.1-1.9, and 70.7% for a margin of 2 cm or more (p = 0.66). The 5-year DSS was 80.3% for a margin of 1 cm, 66.2% for a margin of 1.1-1.9 cm, and 91.8% for a margin of 2 cm or more (p = 0.28). For wound closure, 43.5, 50, and 65.9% of the patients respectively required a flap or graft with a margin of 1, 1.1-1.9, and 2 cm or more (p = 0.006). CONCLUSIONS: A 1-cm resection margins did not increase the risk of LR. Margin width did not make a significant difference in DSS or OS. Larger resection margins increase the need for a graft or flap closure.

The emerging role of radiotherapy for desmoplastic melanoma and implications for future research.

The National Comprehensive Cancer Network (NCCN) 2014 guidelines are unclear about the role of radiotherapy in the management of desmoplastic melanoma. The guidelines specify that radiotherapy can be 'considered' for select patients with desmoplastic melanoma with narrow surgical margins. Patient selection criteria, including margins, are not well defined, causing considerable differences in practice patterns across the country. There are also several conflicting reports about the role of radiotherapy in improving postsurgical outcomes when other adverse pathological risks factors, such as increased Clark level, head and neck involvement, perineural invasion, positive margins, or recurrent disease, are also present. Recent data provide further clarification and insights into the role of radiotherapy. Thus, in light of the NCCN guidelines and the recently published series, we critically review the role of radiotherapy for desmoplastic melanoma. In our review, we highlight the published risk factors that predict for increased risk of recurrence after surgery. We also provide a comparison of surgical and radiation outcomes data, and then address areas for further research.