Phase II Study Evaluating Safety and Efficacy of Tislelizumab for Elderly Patients Unfit for Chemotherapy, With Advanced Esophageal Squamous-cell Carcinoma

Inclusion Criteria: * Histologically proven esophageal squamous cell carcinoma (ESCC) * Metastatic or locally advanced cancer * Absence of previous treatment (immunotherapy, chemotherapy or radiotherapy) in first line setting * Ineligibility for a platinum-based chemotherapy assessed by oncologist and geriatrician * At least one evaluable and/or measurable lesion as defined by RECIST v1.1 criteria * Patients ≥ 70 years * Subjects with WHO performance status ≤ 2 * Estimated life expectancy \>3 months * Adjuvant therapy finished \>6 months * Adequate marrow and organ functions defined as: * Absolute neutrophil count (ANC) ≥ 1 × 109/L, * Platelet count ≥ 75 × 109/L, * Hemoglobin ≥ 90 g/L, * Aspartate transaminase (AST) and alanine transaminase (ALT) ≤ 3 × ULN, or AST and ALT ≤5 ×ULN for patients with liver metastases * ALP ≤ 5 x ULN unless liver metastases are present, in which case it must be ≤ 10x ULN * Measured creatinine clearance (CL) \> 40 mL/min (MDRD method) * Male patients must use a condom during treatment and for 6 months after the last dose when having sexual intercourse with a pregnant woman or with a woman of childbearing potential. Female partners of male patients should also use a highly effective form of contraception if they are of childbearing potential during treatment and for 6 months after the last dose. * Patient is willing and able to comply with the protocol for the duration of the study including undergoing treatment, scheduled visits and …