A Practical Update of Surgical Management of Merkel Cell Carcinoma of the Skin

Table 6

Summary of surgical management of MCC (NCCN guidelines) [9].

(1) Surgery is the mainstay of treatment for MCC. Radiotherapy is an inferior option for cancer control since the complete response of gross disease of MCC to radiotherapy is only 75%.
(2) It is always best to perform the SLN biopsy before definitive local excision. After wide local excision, SLN biopsy may be considered in selected patients, although accuracy of results may be compromised especially in nonextremity regions.
(3) Resection margin: 1-2 cm. Clear surgical margins when clinically feasible but surgeon should take into account cosmetic and functional outcomes. Close or positive margins should always be followed by adjuvant radiotherapy.
(4) Different surgical techniques: local excision, wide local excision, Mohs technique, modified Mohs (Mohs technique with additional final margin for permanent section assessment), and CCPDMA (complete circumferential and peripheral deep margin assessment).
(5) Any reconstruction involving extensive undermining or tissue movement is delayed until negative histological margins are verified. When primary closure is not possible, consider split-thickness skin graft as it is easier to monitor recurrence.
(6) In the head and neck region, risk of false-negative SLN biopsy is higher, due to aberrant lymph node drainage and frequent presence of multiple SLN basins. SLN biopsy is therefore not mandatory.
(7) SLN assessment—sensitivity of cytokeratin-20 immunohistochemical staining is over 90% and must be used. It can detect micrometastasis missed by H&E staining.

H&E: hematoxylin and eosin; NCCN: National Comprehensive Cancer Network; SLN: sentinel lymph node.