Identifying the factors that influence surgeon's compliance with excisional margins of non-melanoma skin cancer

The rising incidence of Non Melanoma Skin Cancers (NMSC) leads to a high number of surgical procedures worldwide. The strict compliance with international guidelines with regard to excisional margins may help decrease the number of re-excision procedures and reduce the risk of NMSC recurrence. The aim of this study was to investigate the prevalence of excisional margins as recommended by the European Academy of Dermatology and Venereology (EADV) and the European Dermatology Forum (EDF) guidelines, and the factors (demographic or clinical) that influence surgeons' compliance with these guidelines. This was a prevalence study looking at surgical excisions of NMSCs performed over a period of 2 years (2011 - 2012). A sample size of 1669 patients was considered. Definition of excisional margins recommended by the international guidelines (EADV and EDF) were used as point of reference for the analysis. Tumor and histologic specimen size were calculated ex vivo by 5 different pathologists. The size of skin specimens was measured with a major axis and a minor axis. The same was done for the tumor present on the skin specimens. The differences between the major and minor axes of surgical specimen and tumor were calculated. These differences were subsequently divided by two, hypothesizing that the lesion had the same distance from the margins of the surgical specimen. The differences obtained were named ''Delta'' , the formulas applied being the following: Delta major = (major axis specimen-major axis tumor)/2; Delta minor = (minor axis specimen-minor axis tumor)/2. Results show a significant statistical difference, associated with factors such as: age of the patient, anatomical localization of the tumor, histological diagnosis, and surgeons' experience. The identification of these factors sheds light on clinicians' practice and decision-making regarding excisional margins. Hopefully a higher level of adherence to the guidelines can be achieved in the future.