The primary objective is to determine whether in children undergoing doxorubicin-containing chemotherapy, if topical vitamin E, when compared to placebo, decreases an objective measurement of oral mucositis.

Oral mucositis is a common consequence of chemotherapy and is an important sequela of cancer therapy because it is painful and affects quality of life, may lead to hospitalization for hydration or pain control, and provides a portal of entry for oral microflora. In addition, oral mucositis has become a major dose-limiting toxicity and consequently, may limit delivery of anti-cancer therapy.

Despite the frequency of mucositis, there are no feasible therapies proven to be successful in preventing mucositis in children. Vitamin E is a fat-soluble essential vitamin that may protect against doxorubicin-induced oral mucositis through its anti-oxidant properties.

In this study, we will examine the efficacy of topical vitamin E as prophylaxis against chemotherapy-induced mucositis with a novel methodology appropriate for the study of rare conditions, namely combining N-of-1 trials using Bayesian meta-analysis.

The primary outcome is an objective mucositis score measured on days 7, 10, 14 and 17. Secondary outcomes included daily pain and swallowing visual analogue scale scores, and World Health Organization mucositis scores collected on days 5 to 20.

Comparisons: Objective and subjective mucositis scores will be compared in cycles associated with topical vitamin E versus cycles associated with placebo administration. We will use repeated measures analysis within a Bayesian framework in order to conduct this comparison.

Inclusion Criteria:

• diagnosis of cancer and treated at the Hospital for Sick Children, Toronto, Canada
• planned chemotherapy includes at least two identical courses of doxorubicin-containing chemotherapy in which the dose of doxorubicin was at least 60 mg/m2 per course
• at least 6 years of age and less than 18 years
• lives in the Greater Toronto area

Exclusion Criteria:

• allergy to vitamin E or placebo ingredients
• child is unable to comply with topical vitamin E application
• cild is receiving head or neck irradiation