Defining recurrence of nonmelanoma skin cancer after Mohs micrographic surgery: Report of the American College of Mohs Surgery Registry and Outcomes Committee

Background Standardized definitions and methods of surveillance for local recurrence of nonmelanoma skin cancer are critical in determining cure rates attributed to treatment modalities. Objective We sought to offer a standard definition of local recurrence after surgical treatment of nonmelanoma skin cancer and to propose an acceptable surveillance period and tracking methods. Methods A literature search was performed for background definitions of local recurrence and tracking methods. The American College of Mohs Surgery (ACMS) Registry and Outcomes Committee then conducted a modified Delphi process to arrive at consensus definitions. Results We define local recurrence as a tumor with comparable histology, with contiguity to the surgical scar after treatment, and that arises within the area of the previously treated tumor. Limitations This project reports the results of a modified Delphi method process involving members of the ACMS. The model described may not be useful for nonexcision type treatments such as topical chemotherapy, electrodessication and curettage, or radiation treatment. Conclusions Previous definitions of recurrence and surveillance methods after surgical treatment of nonmelanoma skin cancer are variable and nonstandard. We describe consensus standards for defining and tracking recurrence that should allow for consistent scientific evaluation and development of performance data in skin cancer outcomes registries.