Evidence‐based management of primary and localized Merkel cell carcinoma: a review

Abstract

For primary tumors without evidence of organ metastases, surgical excision should be the primary therapy. Owing to the high rate of local metastases, a safety margin of at least 2 cm should be considered. In situations where small, localized tumors and/or special locations necessitate a smaller safety margin, compensation by complete histological examination of the excision margins and perhaps adjuvant radiation therapy should be undertaken. The literature states that benefits of Mohs micrographic surgery (over wide local excision) include tissue conservation and identification of tumors that may require extremely wide excision margins. The majority of data to date supports the use of Mohs surgery in the treatment of Merkel cell carcinoma.

Merkel cell carcinoma

“…Furthermore, in the literature, there is no formal evaluation of appropriate excision margins and the risk of recurrence. However, the local recurrence rate is significantly higher with small excisions and is particularly high in case of positive surgical resection margins 105,115 (that is, if tumour cells are present at the edge of the excised tissue). The National Comprehensive Cancer Network (NCCN) and the European Association of Dermato-Oncology (EADO)–European Organisation for Research and Treatment of Cancer (EORTC) guidelines recommend a 1–2 cm excision margin down to the muscle fascia or the pericranium (the membrane that externally covers the skull), regardless of tumour size 81,82,116 .…”

“…The National Comprehensive Cancer Network (NCCN) and the European Association of Dermato-Oncology (EADO)–European Organisation for Research and Treatment of Cancer (EORTC) guidelines recommend a 1–2 cm excision margin down to the muscle fascia or the pericranium (the membrane that externally covers the skull), regardless of tumour size 81,82,116 . When functional considerations are important, excision can be performed with microscopically controlled surgery and complete histological inspection of the margins of the excised material to confirm complete resection of the tumour can be considered, but experience is limited in MCC 115,117,118 . Of note, the safety margin is intended to remove microscopic satellite metastases rather than to ensure clear resection margins of the primary tumour 81,82 .…”

The role of PPARγ‐mediated signalling in skin biology and pathology: new targets and opportunities for clinical dermatology

“…Indeed, administration of PPARc agonists to psoriatic patients associates with amelioration of symptoms and skin lesions (Table S1). The systemic administration of troglitazone and pioglitazone improved skin lesions in psoriatic patients (52)(53)(54)(55), whereas rosiglitazone was ineffective either systemically or topically underlining how different ligands lead to diverse biological effects (56,57).…”

Merkel cell carcinoma: what makes a difference?

“…Currently, adjuvant RT is advocated because MCC has a high incidence of nodal and metastatic disease. 27,28 A previously unaddressed question was whether RT was beneficial in those patients specifically known to be node negative. Our study found that there was no statistical survival advantage to giving adjuvant RT to patients with a negative SLNB.…”

“…In their review, Ellis and Davis suggested that RT should be optional for patients at lowest risk for locoregional failure, including immunocompetent patients with primary tumors less than or equal to 1 cm with no adverse histologic features, whose WLEs show clear margins and whose SLNB is negative. 28,29 Chemotherapy has traditionally been reserved as more of a palliative and salvage option, although MCC is considered to be chemosensitive. Although high remission rates of up to 70% are seen, there has been no survival benefit.…”