Mohs micrographic surgery on par with wide local excision for Merkel cell carcinoma

Mohs micrographic surgery (MMS) as the surgical modality for primary cutaneous Merkel cell carcinoma (MCC) is not inferior to wide-local excision (WLE), showing no survival disadvantage, according to a recent study.

The authors compared overall and MCC-specific survival outcomes in clinically and pathologically, node-negative MCC patients treated with WLE and MMS in a nationally representative sample. They stratified and analysed overall and MCC-specific survival outcomes for primary MCC tumours contained in the SEER-18 database from 1989 to 2015 by surgical modality and competing risk analysis, respectively.

In total, 2,359 adults with MCC met the inclusion criteria. Multivariable analysis revealed no significant difference in overall and MCC-specific survival between WLE and MMS (hazard ratio [HR], 1.04, 95 percent confidence interval [CI], 0.88‒1.22; subdistribution HR, 0.76, 95 percent CI, 0.53‒1.09).

Notably, sentinel lymph node biopsy significantly correlated with improved overall survival and MCC-specific survival.

“There is no survival disadvantage for MMS compared to WLE as the surgical modality for primary cutaneous MCC,” the authors said. “Sentinel lymph node biopsy should be coordinated prior to MMS.”

The study was limited by the retrospective design of SEER and the lack of covariates such as comorbidities and immunostaining.

“The preferred treatment for clinically node-negative MCC is surgical excision in conjunction with sentinel lymph node biopsy,” the authors said. “There is limited large-scale research on survival outcomes by surgical approach for management of the primary tumour.”