Chemoprevention of squamous cell carcinoma in recessive dystrophic epidermolysis bullosa: Results of a phase 1 trial of systemic isotretinoin

Background: Patients with recessive dystrophic epidermolysis bullosa (RDEB) are at high risk of developing squamous cell carcinoma on or after midadolescence, and most patients die of metastatic squamous cell carcinoma within 5 years of diagnosis of their first squamous cell carcinoma. Objective: We sought to determine whether isotretinoin can be safely administered to patients with RDEB as a possible chemopreventive agent. Methods: A total of 20 patients with RDEB aged 15 years or older were treated daily for 8 months with isotretinoin (with a targeted dosage of 0.5 mg/kg/d). Results: No unusual adverse reactions were noted in this patient population. Several patients experienced reduced blistering at lower doses and increased mechanical fragility at maintenance dosage. Conclusions: Isotretinoin, at least up to a dosage of 0.5 mg/kg/d, may be safely used in patients with RDEB. Although increased fragility may occur, patients tolerated this drug well and were receptive to its long-term use for possible chemoprevention of cancer. Whether such an effect will occur is yet to be proven.