A Study to Investigate Tislelizumab (BGB-A317) Versus Placebo in Combination With Concurrent Chemoradiotherapy in Participants With Localized Esophageal Squamous Cell Carcinoma

Overall survival (OS)

OS is defined as the time from the date of randomization to the date of death due to any cause.

Time frame: From date of randomization up to 4 years, approximately

Change from baseline in European Quality of Life-Core 30 Questionnaire index (EORTC QLQ-C30)

The EORTC QLQ-30 contains 30 questions that incorporate 5 functional scales (physical functioning, role functioning, emotional functioning, cognitive functioning, and social functioning), 1 global health status scale, 3 symptom scales (fatigue, nausea and vomiting, and pain), and 6 single items (dyspnea, insomnia, appetite loss, constipation, diarrhea, and financial difficulties). The participant answers questions about their health during the past week. There are 28 questions answered on a 4-point scale where 1 =Not at all (best) to 4 =Very Much (worst) and 2 questions answered on a 7-point scale where 1 =Very poor (worst) to 7 =Excellent (best).

Time frame: Baseline to end of treatment ~2 years

Change from baseline in European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire esophageal cancer module (EORTC QLQ-OES18)

Total of 18 questions to assess your symptoms or problems during the past week, each assessed on a scale from 1 (not at all) to 4 (very much). with the range from minimum scores 1 as better outcome and maximum 4 as worst outcomes. Symptoms includes whether any difficulty to eating solids, liquidized or softs food, drinking, or not， whether it is difficult to or swallowing, trouble eating or enjoying meals, pain when eating, dry mouth, food tasting differently, trouble talking, ， whether the sense of smell and conversation are normal or not， whether have Symptoms include cough, indigestion or heartburn, acid reflux and pain or not in the chest or stomach.