Local excision (primary, recurrent disease)

While surgery is widely accepted as the mainstay of treatment for primary and recurrent Merkel cell carcinoma, there is great variability in the excision margins employed. In part, this derives from the sparsity of outcomes data regarding surgical extirpation, as much of the data accrued to date has consisted of retrospective reviews of registry and case series, many with small sample sizes, with no level I evidence available to guide therapy. As such, universally accepted treatment protocols for the management of primary and recurrent Merkel cell carcinoma are lacking. Currently, the National Comprehensive Cancer Network guidelines recommend local wide excision with 1–2 cm margins to fascia of muscle or pericranium for the treatment of primary Merkel cell carcinoma, with the intention of achieving negative surgical margins. Alternatively, Mohs surgery or modified Mohs surgery with permanent sections can be considered. With regard to the surgical management of recurrent disease, many questions still remain, and few studies have addressed this subset of patients. In the absence of validated data, the most rational therapeutic approach for these patients may be devising an individualized multidisciplinary treatment plan including consideration of surgical, radiation, and chemotherapeutic strategies.