Sung, L., Tomlinson, G.A., Greenberg, M.L., Koren, G., Judd, P., Ota, S., & Feldman, B.M. (2007). Serial controlled N-of-1 trials of topical vitamin E as prophylaxis for chemotherapy-induced oral mucositis in paediatric patients. European Journal of Cancer, 43, 1269–1275.
Eight hundred mg vitamin E was diluted with corn oil (volume = 2 mL). Patients swished for at least 30 seconds then spat it out. The control group received corn oil only. Subjects did not rinse mouths for 30 minutes after spitting out the solution. Forty-five cycles of the study drug were administered (one cycle: four patients, two cycles: five patients, three cycles: one patient, four cycles: four patients, six cycles: five patients; vitamin E = 22 cycles, placebo = 23 cycles).
Compliance was 84% with no statistically significant findings. Vitamin E was not associated with reduction in pain VAS scores or swallowing difficulty. WHO mucositis scores were similar for vitamin E and placebo cycles. No differences for the additional secondary outcomes between vitamin E and placebo cycles were found. Authors noted that vitamin E should not be used in this context. N-of-1 study design was found to be a potentially effective design method.