Serial controlled N-of-1 trials of topical vitamin E as prophylaxis for chemotherapy-induced oral mucositis in paediatric patients

The objectives were (1) to determine whether in children undergoing doxorubicin-containing chemotherapy, topical vitamin E decreases an objective measurement of oral mucositis compared to placebo, and (2) to assess the feasibility of an innovative trial design in paediatric cancer, combining N-of-1 trials using Bayesian meta-analysis. We conducted a series of N-of-1, double-blinded, randomised controlled trials in children ≥ 6 years of age receiving repeated cycles of identical doxorubicin-containing chemotherapy. Each study cycle was followed by topical vitamin E (800 mg) or placebo. We enroled 16 children and 45 post chemotherapy cycles were randomised to vitamin E (N = 22) or placebo (N = 23). There was no difference in objective mucositis scores with a mean score of 0.2 with vitamin E and 0.3 with placebo. Topical vitamin E does not reduce doxorubicin-induced oral mucositis in children. The use of N-of-1 studies and Bayesian meta-analysis may facilitate the study of some therapies in paediatric oncology.