Analysis of cutaneous Merkel cell carcinoma outcomes after different surgical interventions.

Background: Current guidelines recommend local excision margin (EM) with 1 to 2 cm on primary Merkel cell carcinoma (MCC) sites.

Objective: We compared survival outcomes of patients with MCC who were treated with different surgical interventions.

Methods: A retrospective analysis of MCC cases in the Surveillance, Epidemiology, and End Results database was performed using the Kaplan-Meier, competing risk, and Cox proportional hazards regression model analyses. Influence of age, T stage, American Joint Committee on Cancer stage, adjuvant radiotherapy, and other subgroups were also analyzed by pairwise log rank test.

Results: Our results indicated a significant association between local destruction method and inferior survival, while an EM >2 cm showed significantly higher overall survival. In addition, the competing risk analysis depicted a similar trend as the Kaplan-Meier analysis, and considerably reduced estimated cumulative incidence. Further subgroup pairwise analysis demonstrated that the EM >2 cm method had better survival in patients who were <60 years of age, having smaller tumor diameters (T1 and T2) or having undergone adjuvant radiotherapy (P < .05). In contrast, different EMs did not show any significant association with survival rate in patients ≥75 years of age or stage III tumors.

Limitations: This study was not prospectively randomized without relapse data.

Conclusions: It is challenging to make optimal EM recommendations, because surgical options may depend on individual case situations. Further prospective randomized studies are warranted.