Prediction of surgical margin width using Mohs micrographie surgery for extramammary Paget’s disease based on clinicopathological parameters: classification tree analysis of 150 cases

Extramammary Paget's disease (EMPD) frequently extends beyond clinical borders, causing a high recurrence rate. Mohs micrographic surgery (MMS) has been used for management of EMPD, but its efficiency is compromised by technical limitations inherent in MMS. To identify clinicopathologic parameters of predictive value regarding MMS final margin width (FMW) for EMPD, and provide some preliminary guidance in selecting initial surgical margin width for improved efficiency. This was a retrospective study of 150 consecutive EMPD patients who underwent MMS between 2013 and 2019. Clinicopathological parameters and surgical data were collected to construct a classification tree of FMW. A six-node classification tree with a sensitivity of 86.25% and a specificity of 48.57% was generated. Lesion width, disease duration and inflammation score were used to select subgroups of patients in whom optimal initial margin width may be recommended. Classification tree analysis may help identify important variables to consider when selecting MMS initial surgical margins for EMPD.