BOWTIESurgical Excision Versus Photodynamic Therapy and Topical 5-fluorouracil in Treatment of Bowen's Disease: a Multicenter Randomized Controlled Trial

This is a multicenter randomized controlled non-inferiority trial, conducted in one academic and three non-academic hospitals. A multicenter approach (academic and non-academic centers) increases the generalizability of the study results. The study takes place at the dermatology department of Maastricht University Medical Centre (MUMC+), Catharina hospital Eindhoven, VieCuri Medical Centre Venlo and Zuyderland Medical Centre Heerlen. A non-inferiority design was chosen because although the noninvasive treatments are expected to be somewhat less effective in terms of remaining free of recurrence, there are other benefits such as higher patient satisfaction, patient preferences and better cosmetic outcome. It should be noted that BD is a noninvasive disease and recurrences can be treated with surgical excision without compromising the patient's health. After giving permission and signing the informed consent form, eligible patients will be randomly assigned to one of three treatment groups: 1) PDT, 2) 5% 5FU cream, 3) surgical excision. All interventions are part of regular care. For the treatment of BD 5% 5FU cream (Efudix®) has been approved by the European Medicines Agency (EMA). The coordinating investigator who is not blinded to the randomized treatment will prescribe the 5FU cream or give orders to plan PDT or excision and provide patients with further information. The supervising dermatologist will be blinded to treatment allocation, and will be asked to assess outcome measures such as clearance and cosmetic evaluation. Relevant baseline characteristics will be registered (e.g. prior history of skin cancer, age, gender, use of immunosuppressant medication in history, prior treatments for non-melanoma skin cancer), dermatological description of the lesion, size and localization of the lesion and the histological tumour thickness. The presence of other lesions, besides the target lesion, and their treatment will be recorded The primary outcome will be the proportion of patients with sustained clearance at 12 months follow-up after the end of treatment. Secondary outcomes will be the proportion of patients with clearance at 3 months, the long-term probability of sustained clearance, cost-effectiveness, patient satisfaction, compliance, side effects and cosmetic outcome. Residual tumour at 3 months follow-up and recurrent tumour at 12 months follow-up is considered as treatment failure and will be treated with surgery.