Identification of changing melanocytic lesions in patients on BRAF inhibitor therapy.

Abstract

9018 Background: Patients treated with BRAF inhibitors (BRAFi) have been observed to develop new primary melanomas. In addition, these patients often develop new nevi and involuting nevi. It remains a challenge to detect clinically subtle and histopathologically early melanomas in a background of such increased nevus volatility. In this study, we sought to quantify and describe the new, changing, and involuting melanocytic lesions observed in these patients. Methods: A retrospective chart and image analysis was conducted for all BRAFi treated patients referred to the Dermatology service at Memorial Sloan-Kettering Cancer Center. Initial overview and follow-up images were compared in MIRROR Body Mapping image system, DermaGraphiX software (Canfield Imaging Systems, Fairfield, NJ). A total count of new, changing, and involuting melanocytic lesions was determined in four anatomic areas: upper back, lower back, chest, and abdomen. Dermoscopy images of all changing lesions that were biopsied were evaluated for dermoscopic pattern and for the presence or absence of any melanoma specific features. Results: Average photography follow-up was 261 days (n=21). The average number of combined new and changing melanocytic lesions was 13.1, 16.4, 9.5, and 6.1 for the upper back, lower back, chest, and abdomen respectively. The average number of involuting melanocytic lesions was 8.0, 4.0, 4.3, and 3.4 for the upper back, lower back, chest, and abdomen respectively. Of all new and changed lesions, 38 were biopsied revealing 31 benign melanocytic lesions and 7 melanomas (18% of lesions biopsied). All 7 melanomas revealed at least one melanoma specific structure, with the most significant dermoscopic discriminate being negative network. Conclusions: Given the setting of highly volatile melanocytic changes in BRAFi treated patients and that 18% of biopsied lesions were melanomas; we propose the use of total body photography and dermoscopy as a method for the identification and monitoring of secondary atypical pigmented lesions.