Efficacy and safety analysis: 24‐month outcomes from a prospective cohort of 106 fields treated with widefield radiation therapy for extensive skin field cancerization, with or without keratinocyte cancers

AbstractBackgroundWidefield radiation therapy (RT) has emerged as a treatment option for extensive skin field cancerization (ESFC), with or without keratinocyte cancer (KC).ObjectivesTo assess the long‐term efficacy, safety, cosmesis and quality of life outcomes for patients with ESFC ± KC receiving widefield RT.MethodsNDROR (National Dermatology Radiation Oncology Registry) is an open‐label, prospective, nonrandomized, multicentre registry of patients receiving widefield RT at 11 Australian radiation oncology clinics from a single organization. Field/lesion clearance efficacy and cosmesis were assessed in a cohort of patients with at least 24 months follow‐up. Patient‐reported quality of life using EQ‐5D‐5L questionnaires was performed at each visit. Toxicity analysis was performed on data from patients who completed treatment and had at least 3 months follow‐up.ResultsCombined investigator‐assessed field treatment success and lesion clearance at 24 months were ≥96% and 93.5%, respectively. The incidence of new KC within the treated field was 10%. Common Terminology Criteria for Adverse Event grade 1–2 radiation‐induced skin toxicities were reported in >92% of fields at the end of treatment, with 5.8% of fields exhibiting grade 3 toxicities. Toxicity resolved rapidly at the cessation of treatment, with grade 1–2 alopecia and xerosis the most prevalent toxicities after 24 months (51.8% and 43.4%, respectively). Cosmesis in treated fields was assessed as excellent or good in 98% of fields at 24 months. Quality of life significantly improved compared to baseline (baseline: mean visual analogue scale (VAS) 80.65, n = 183) at 24 months follow‐up (mean VAS 84.32, N = 83; improvement of 3.67; p = 0.026).ConclusionsThis analysis indicates that widefield RT is an effective and generally well‐tolerated treatment for ESFC ± KC. Treatment has a favourable safety and cosmesis profile within the period of follow‐up and is associated with significant improvements in quality of life for patients. Widefield RT may be considered for certain patients with extensive disease who have exhausted or are unsuitable for other therapies.