Background/Rationale: Neurofibromatosis type 1 (NF1) affects about 1 in every 3000 people worldwide. Globally, 30~50% NF1 patients will develop plexiform neurofibromas (PNs), which grow rapidly in early childhood and can cause disfigurement, motor dysfunction, pain, airway dysfunction, visual impairment and bladder and bowel dysfunction. This systemic disease imposes a heavy psychosomatic and financial burden on patients and their caregivers. In NF1 patients, the lifetime risk of MPNST developed from PN is 8% to 13%. The mean age for NF1-associated death was approximately 20 years lower than that for the general population. Limited epidemiological and clinical data of Chinese NF1 patients is available to date. And the treatment pattern of Chinese NF1-PN patients is also unknown.

Objectives and Hypotheses: It is a descriptive study without formal hypothesis. The primary objective of this study is determining the percentage of NF1 patients who develop PN. The secondary objectives of this study include describing the clinical characteristics, tumor progression and treatment pattern of NF1-PN. The exploratory objective is exploring the epidemiological characteristics of other NF1 manifestations.

Methods:

Study design: The study is a retrospective multi-center chart review study. Data Source(s): All the data will be collected by CRF from inpatient and outpatient electronic medical records in every study site from January 1, 2019 to December 31, 2022.

Study Population: Patients who attended the study sites between January 1, 2019 - December 31, 2022 and were diagnosed with NF1 were included in this study. Statistical Analysis: This study is purely descriptive without any formal hypotheses.

Missing data for baseline characteristics will be assessed and addressed as a categorical variable with a level for missingness. All reported measures will be summarized in the study tables. Point estimates and their 95% CIs will be presented in the final analyses.

Inclusion Criteria:

1. Patients who attended the study sites between January 1, 2019, and December 31, 2022.
2. Patients who were diagnosed with NF1(recorded with the text of type I neurofibromatosis) based on National Institutes of Health (NIH) NF1 consensus.

Exclusion Criteria:

1. Patients combined with other malignant tumors

Patients will be included in this study if they: 1) attended the study sites between January 1, 2019 and December 31, 2022; 2) were diagnosed with NF1 based on NIH NF1 consensus (Version 1987 or Version 2021); and 3) were not diagnosed with other malignant tumors from 2019.1.1 to 2022.12.31. As this study was a chart review, there was no systematic follow-up. Follow-up was based on individual patient needs, was not dictated by the study, and varied from person to person in a manner reflective of real clinical practice. Thus, patients were followed up until end of data availability, death, or loss of follow up, whichever comes first.