Presurgical Curettage Improves Accuracy for Nonmelanoma Skin Cancer Excision

Abstract

Background Presurgical curettage before nonmelanoma skin cancer surgery may help delineate tumor subclinical extensions. Objective To determine histologically whether presurgical curettage appropriately or inappropriately changes excision specimen size. Materials and Methods One hundred fifty consecutive nonmelanoma skin cancers treated with Mohs micrographic surgery. The clinical margin (CM) was marked. Presurgical curettage was then performed and the resultant presurgical curettage margin (PCM) marked. Frozen section analysis of the CM and PCM revealed whether the curettage-induced margin change was appropriate or unnecessary. Results Presurgical curettage appropriately increased the surgical margin in 9.3% of cases, reducing the number of Mohs stages from 2 to 1. It appropriately decreased the surgical margin in 17.3% thereby conserving normal skin. In 19.4% of cases the curettage increased the margin in situations where the CM had underestimated the size of the tumor; however, in these cases, the curettage did not increase the margin sufficiently to clear the tumor. In 44.0% of cases the PCM did not change the size of the stage I specimen compared to the CM and confirmed the CM. In 10.0% of cases, preoperative curettage reduced margin accuracy by removing healthy tissue (8.0%) or underestimating tumor (2.0%). These errors were associated with eyelid location, severe background photodamage, and morpheiform/infiltrating/sclerosing basal cell carcinomas. Conclusion Presurgical curettage can improve tumor excision accuracy and efficiency. Careful tumor selection is important to optimize curette utility.