Melanoma in individuals with neurofibromatosis type 1: A retrospective study

Background: Neurofibromatosis type 1 (NF1) is a cancer syndrome associated with many different cancer types. There are limited studies examining melanoma risk in this population. Objective: To identify melanoma cases in NF1 patients and compare melanoma incidence rates relative to a general population sample. Methods: A retrospective single institution case review of 857 NF1 patients (seen from 7/1997 to 7/2017) was conducted. We calculated age- and calendar period-adjusted standardized incidence ratios (SIRs) for white patients >20 years old overall (N=282) and for females (N=156) at their last visit date. We obtained general population melanoma reference rates from the Surveillance, Epidemiology, and End Results (SEER) 9 database. Results: Among 857 patients, 52.2% were female, 54% were <20 (mean±sd=10.9±4.6) years old, and 46% were >20 (40.4±14.9) years old at their last visit date. One white female patient had a malignant melanoma diagnosed at 47 years old. The adjusted SIR was 0.97 (95% CI 0.05-4.78) overall (N=282) and 1.62 (95% CI 0.08-7.98) for females (N=156). Conclusions: We did not find statistical evidence for an increased melanoma risk in adults with NF1. However, additional large studies are warranted to clarify whether melanoma risk is increased in NF1 patients.