Statistical analysis and evaluation criteria for the endpoints
dysphagia, dry mouth
DYSPHAGIA, ADVERSE EVENTS, HEARING IMPAIRMENT, HYPOTHYROIDISM, DRY MOUTH
A 3-year TTF1 of 50% is assumed for both arms. According to the Schoenfeld and Richter’s method [If the experimental arm is non-inferior to the standard arm in terms of TTF1 and superior in terms of safety endpoints, the 2-step40 method will be considered the more efficacious treatment. However, it is unacceptable that a point estimate of 3-year OS in the experimental arm is more than 5% lower than that in the standard arm. Based on mathematical models, the rates of key late adverse events of grade 2 or higher are expected to be reduced by approximately 15%, 7%, 7%, and 10% for hearing impairment, hypothyroidism, dry mouth, and dysphagia, respectively. If the experimental arm shows sufficient improvement in at least one of these key late adverse events, the study treatment will be considered as beneficial. If the non-inferiority of the experimental arm in terms of the primary endpoint is not demonstrated, the SIB56 method will be considered a useful treatment.