The post hoc analysis comparing the severity grades of chemoradiotherapy-induced oral mucositis scored between the central and local assessors in a multicenter, randomized controlled trial of rebamipide for head and neck cancer

Background In the treatment of head and neck cancer, severity of chemoradiotherapy-induced oral mucositis has been recognized as one of the key factors affecting the outcomes of the anticancer therapies. Therefore, the development of treatments mitigating oral mucositis would be of clinical significance, although the adequate assessment procedure for efficacy evaluation remains to be established. We conducted this post hoc study to assess the effect of objective evaluation of the severity grade on the outcomes of the clinical trial. Methods In the original trial with rebamipide liquids (0, 2, and 4%) for chemoradiotherapy-induced oral mucositis, the investigators in local sites and independent central review separately determined the severity grades in accordance with Common Terminology Criteria of Adverse Events version 3.0 based on the Assessment Sheet scored by the investigators. The discordance in severity grades between the investigators and central review was analyzed on cross table. Results The analysis revealed the discordance rate over the trial was 34%. While the incidences of severe oral mucositis in the placebo, rebamipide 2%, and 4% groups evaluated by the central review were 39%, 29%, and 25%, respectively, the respective values in the investigator’s evaluation were 32%, 39%, and 44%. Conclusion In the clinical trial for the treatment of oral mucositis, it was strongly suggested that objective evaluation with a consistent scale would be required.