P215 Incidence, demographics and survival of atypical fibroxanthoma in England: a population-based study 2013–2022

Abstract

Atypical fibroxanthoma and atypical fibrous histiocytoma (AFX) are rare cutaneous tumours of uncertain malignant potential that mainly affects older adults. Population-level epidemiological data are limited. The aim of this study was to characterize temporal trends in incidence, demographic distribution and survival outcomes of atypical fibroxanthoma (AFX) in England. We analysed data from the National Disease Registration Service (NDRS), England for patients diagnosed with AFX between 2013 and 2022 from the Get Data Out programme. Annual counts, and crude and age-and-gender-standardized incidence rates per 100 000 persons with 95% confidence intervals (CIs) are reported. Five-year overall Kaplan–Meier and net survival are reported for the 2014–16 cohort. Annual counts increased from 355 cases in 2013 to 600 in 2022 (+59%). Crude incidence rates rose from 0.66 in 2013 (95% CI 0.59–0.73) to 1.08 in 2019 (95% CI 0.99–1.17) and remained stable through 2019–2022. The standardized incidence rate increased from 0.87 (95% CI 0.78–0.97) in 2013 to a peak of 1.28 (95% CI 1.18–1.39) in 2019, with minimal variation there­after. AFX predominantly affected adults aged > 60 years and peaked in the 75–89-year age groups. The male-to-female ratio was 3 : 1. Most cases occurred in those of White ethnicity (90–92%), with small numbers in other ethnic groups. Incidence increased with decreasing socioeconomic deprivation. Five-year net survival and overall survival were 91.6% (95% CI 86.6–96.5) and 64.3% (95% CI 61.6–66.8), respectively, which are similar to rates in cutaneous squamous cell carcinoma and melanoma. As AFX is registered in the NDRS as a tumour not considered to be malignant, variation in local NHS diagnostic and reporting practices may not be optimized to capture all cases and some data may be missing or misclassified. The incidence of AFX in England has increased over time. European population-based studies have reported incidence estimates of 0.5–0.6 per 100 000 person-years. National databases provide an important resource to better understand rare diseases.