Our team based in Seattle conducted a comprehensive review including evolving trends in the management of Merkel cell carcinoma (MCC). This summary covers key decision points, including recommended work-up during initial diagnosis, treatment options for MCC when it’s in one place or has spread, management of recurrent MCC, and new treatments that are showing promise with fewer side effects and good results. This review gives valuable information on how to handle MCC overall and emphasizes new methods that are effective and less toxic on patients.
Background: Merkel cell carcinoma (MCC) management typically includes surgery with or without adjuvant radiation therapy (aRT). Major challenges include determining surgical margin size and whether aRT is indicated.
Objective: To assess the association of aRT, surgical margin size, and MCC local recurrence.
Methods: Analysis of 188 MCC cases presenting without clinical nodal involvement.
Results: aRT-treated patients tended to have higher-risk tumors (larger diameter, positive microscopic margins, immunosuppression) yet had fewer local recurrences (LRs) than patients treated with surgery only (1% vs 15%; P = .001). For patients who underwent surgery alone, 7 of 35 (20%) treated with narrow margins (defined as ≤1.0 cm) developed LR, whereas 0 of 13 patients treated with surgical margins greater than 1.0 cm developed LR (P = .049). For aRT-treated patients, local control was excellent regardless of surgical margin size; only 1% experienced recurrence in each group (1 of 70 with narrow margins ≤1 cm and 1 of 70 with margins >1 cm; P = .56).
Limitations: This was a retrospective study.
Conclusions: Among patients treated with aRT, local control was superb even if significant risk factors were present and margins were narrow. We propose an algorithm for managing primary MCC that integrates risk factors and optimizes local control while minimizing morbidity.