RF05 A national report on incidence, patient demographics and tumour characteristics of melanoma by BRAF, NRAS and KIT genotype: England 2016–2019

Abstract

Abstract Although studies have shown variation between countries in the incidence and characteristics of patients and tumours associated with melanoma BRAF, NRAS and KIT mutations, no national molecular genetics data from England have been published. In 2022, the National Institute for Health and Care Excellence highlighted the need for national cohort studies to evaluate the role of biomarkers. This descriptive national observational study used National Disease Registration Service (NDRS) data to identify all site melanoma cases that were diagnosed and underwent molecular genetic testing in England between 2016 and 2019. The NDRS collects molecular genetics data from most genomic laboratories nationally but does not routinely receive results for BRAF testing by immunohistochemistry (IHC) done at local pathology laboratories. Molecular genetic testing and incidence of wild-type (WT), BRAF mutant (+), NRAS+ and KIT+ melanomas were described. Demographic (sex, age, ethnicity, deprivation, geographical region) and tumour factors (site, stage) of BRAF+, NRAS+, KIT+ and WT tumours were described. In total, 61 514 new melanomas were registered in England between 2016 and 2019. Thirteen per cent (n = 7925), 5.0% (n = 3084) and 1.2% (n = 743) of tumours underwent BRAF, NRAS and KIT testing, respectively. BRAF testing rates varied across regions from 19.9% (n = 1040/5217) in the West Midlands to 5.5% (n = 227/4114) in the North East. Thirty-four per cent (n = 2674/7925), 30.5% (n = 942/3084) and 8.6% (n = 64/743) of tumours were BRAF+, NRAS+ and KIT+, respectively. Thirty-four per cent (n = 1523/4479) of males and 37.6% (n = 1132/3014) of females with cutaneous melanomas were BRAF+. Forty-six per cent (n = 1693/3712) of patients aged < 70 years and 20.5% (n = 332/1622) aged ≥ 80 years were BRAF+. The highest proportion of BRAF+ cutaneous melanoma were identified in the North East (46.7%, n = 106/227) and the lowest in the West Midlands (32.6%, n = 339/1040). Thirty-two per cent (n = 560/1760) of males and 30.0% (n = 349/1167) of females with cutaneous melanoma were NRAS+. Twenty-six per cent (n = 356/1354) of patients aged < 70 years and 31.8% (n = 229/718) aged ≥ 80 years were NRAS+. The highest proportion of NRAS+ cutaneous melanoma were in the West Midlands (40%, n = 14/35) and the lowest in the North East (28.3%, n = 36/127). We report the largest and most complete dataset for national molecular genetics of melanoma ever published. Regional differences in BRAF testing may be explained by variations in local practice and methods used, and differences in population age, but could impact on treatment options. Lack of IHC, testing nonuniformity and lack of whole melanoma population data (early-stage nonrecurrent tumours and tumours in frail elderly patients may be excluded) were limitations.