Incidence of Malignant Peripheral Nerve Sheath Tumor (MPNST) Development in Participants With Neurofibromatosis Type 1 (NF1) Receiving and Not Receiving Medical Therapies Directed at Plexiform Neurofibromas (PN)

Study Description: This is a retrospective review that includes all patients with NF1 enrolled on natural history and treatment trials at the National Cancer Institute (NCI) from 1/1/1998 to 1/1/2020, excluding patients referred for treatment of MPNST. Objective: To describe the clinical and demographic characteristics of NF1 study participants who come for evaluation at the NCI and to compare the risk of MPNST formation in patients treated with MEK 1/2 inhibitor (MEKi) or other PN-directed treatment. Study Population: All participants with NF1 seen at the NIH from 1/1/1998 to 1/1/2020 Description of Sites/Facilities conducting research: This is a single site study initiated by the Pediatric Oncology Branch at the National Cancer Institute Study Duration: Data abstraction to completion of data analyses will take 3-6 months.