Mohs micrographic surgery vs. standard surgical excision?: reply from authors

In a letter to the editor by Slater et al as a reaction to our article on the recurrence rates of cutaneous squamous cell carcinoma of the head and neck after Mohs micrographic surgery versus standard excision1 , it is questioned how the specimens from standard surgical excision were handled pathologically. In our study, in both study centres during the entire inclusion period (2003-2012), specimens were handled pathologically in a standardized and high quality manner which is in line with the 2012 Royal College of Pathologists ( RCPath) skin cancer dataset for primary cutaneous invasive squamous cell carcinoma.2 Therefore, we disagree with the explanation by Slater that our observed differences between Mohs micrographic surgery and standard excision in recurrence rate (3% versus 8%) is caused by poor quality of pathological sampling of excision specimens. The lower risk of recurrence after Mohs micrographic surgery than standard excision is most likely caused by the fact that with Mohs micrographic surgery the entire excision margins are histologically reviewed. In contrast, with standard excision the entire margins are not entirely reviewed, not even when small step sections are made.