No difference in survival for primary cutaneous Merkel cell carcinoma after Mohs micrographic surgery and wide local excision

May 23, 2023


Journal of the American Academy of Dermatology

Publication Date

May 23, 2023


Moore KJ, Thakuria M, Ruiz ES Summary

This study compared two surgical approaches, wide local excision (WLE) and Mohs micrographic surgery (MMS), in the treatment of Merkel cell carcinoma (MCC). The researchers found no significant difference in overall survival or MCC-specific survival between the two approaches. However, MMS has other advantages, such as evaluating a larger portion of the margins and being tissue sparing, which can be beneficial for sensitive areas, such as the head and neck, or for larger tumors. The study also found that there are lower rates of sentinel lymph node biopsy (SLNB) being performed in patients undergoing MMS compared to WLE, despite SLNB being associated with improved survival outcomes. The researchers suggest that if MMS is used to treat MCC, surgeons should ensure that SLNB can be performed prior to resection.


Background: The preferred treatment for clinically node-negative Merkel cell carcinoma (MCC) is surgical excision in conjunction with sentinel lymph node biopsy. There is limited large-scale research on survival outcomes by surgical approach for management of the primary tumor.

Objective: To compare overall and MCC-specific survival outcomes in clinically and pathologically, node-negative MCC patients treated with wide-local excision (WLE) and Mohs micrographic surgery (MMS) in a nationally representative sample.

Methods: Overall and MCC-specific survival outcomes for primary MCC tumors contained in the SEER (Surveillance, Epidemiology, and End Results)-18 database from 1989 to 2015 were stratified by surgical modality and analyzed via competing risk analysis.

Results: A total of 2359 US adults with MCC were included in the analysis. For overall and MCC-specific survival, there was no significant difference in survival outcomes between WLE and MMS on multivariable analysis (hazard ratio, 1.04 [95% CI, 0.88-1.22]; subdistribution hazard ratio, 0.76 [95% CI, 0.53-1.09]). Sentinel lymph node biopsy was associated with improved overall survival and MCC-specific survival.

Limitations: Retrospective design of SEER and the lack of covariates such as comorbidities and immunostaining.

Conclusion: There is no survival disadvantage for MMS compared to WLE as the surgical modality for primary cutaneous MCC. Sentinel lymph node biopsy should be coordinated prior to MMS.

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