Survival in Merkel cell carcinoma may improve with Mohs vs. wide local excision

Key takeaways:

• Association between Mohs and survival was stronger than with wide local excision (HR = 0.59).
• 81.8% of Mohs-treated patients had a 10-year survival rate compared with 60.9% treated with wide local excision.

Patients with Merkel cell carcinoma may have better survival outcomes when treated with Mohs micrographic surgery compared with wide local excision, according to a study.

“Merkel cell carcinoma (MCC) is a rare neuroendocrine skin cancer with a rapidly increasing incidence in the U.S. and around the world,” Shayan Cheraghlou, MD, a resident physician at NYU Grossman School of Medicine, and colleagues wrote. “Compared with other cutaneous cancers, including malignant melanoma, MCC has among the highest rates of associated mortality.”

Current guidelines from the National Comprehensive Cancer Network state that Mohs micrographic surgery (MMS) and wide local excision (WLE) can both be used to treat MCC. However, due to the limited data on this rare disease, there is some controversy surrounding which treatment approach is better, according to Cheraghlou and colleagues.

In this retrospective cohort study, the researchers evaluated the association of surgical approach with overall survival after excision of localized T1/T2 MCC. The study included data from 2,313 patients (mean age, 71 years; 57.9% men) with T1/T2 MCC from the National Cancer Database.

Results showed that excision with MMS had the best unadjusted survival rates when compared with WLE. Survival rates among patients who underwent MMS were 87.4% after 3 years, 84.5% after 5 years and 81.8% after 10 years. In comparison, survival rates among patients who underwent WLE were 86.1% after 3 years, 76.9% after 5 years and 60.9% after 10 years.

Survival rates among patients who underwent narrow-margin excision were similar to those who underwent WLE, with 84.8% of patients surviving after 3 years, 78.3% after 5 years and 60.8% after 10 years.

The researchers’ multivariable survival analysis confirmed that the association between MMS and improved survival was much stronger than with WLE (HR = 0.59; 95% CI, 0.36-0.97).

Cancer centers that treat a high volume of MCC cases were also much more likely to use MMS than WLE compared with other centers (OR = 1.99; 95% CI, 1.63-2.44), indicating that MMS may be the better treatment option of the two.

The authors note that all T1/T2 MCCs were pathologically confirmed as node-negative and emphasize that, moving forward, all MCCs should undergo pathologic confirmation of negative regional lymph node disease.

“Our findings suggest that MMS provides a survival advantage over conventional excision provided that tumors are localized; however, this can only be truly confirmed via pathologic node evaluation,” the authors concluded.