Observational Study of Patients Treated With Nivolumab and Chemotherapy for Advanced or Metastatic Esophageal, Gastroesophageal or Gastric Cancer in France

Inclusion Criteria:

Cohorts 1 & 2

• Adult participants (at least 18 years of age at time of treatment decision)

• Participants treated with nivolumab in combination with fluoropyrimidine- andplatinum-based chemotherapy (according to the French current marketingauthorization) for the treatment of Gastric Adenocarcinoma, Gastro-EsophagealJunction (GEJ) adenocarcinoma, Esophageal Adenocarcinoma (EAC) or EsophagealSquamous Cell Carcinoma (ESCC) and prior to study participation.

• Participants who provided oral informed consent to participate in the study

Cohort 1 only • Diagnosis of untreated HER2 negative advanced or metastatic gastric adenocarcinoma, GEJ adenocarcinoma or EAC whose tumor express PD-L1 with a CPS ≥5

Cohort 2 only

• Diagnosis of untreated unresectable advanced, recurrent or metastatic ESCC with tumor cell PD-L1 expression (TPS) ≥1%

Exclusion Criteria:

Cohorts 1 & 2

• Participants with a primary diagnosis of a cancer other than advanced or metastaticgastric adenocarcinoma, GEJ adenocarcinoma, EAC or ESCC, within the past 5 years.

• Participants currently enrolled in an interventional clinical trial for his/heradvanced or metastatic gastric adenocarcinoma, GEJ adenocarcinoma, EAC or ESCC.

• Pregnant women

• Participants under guardianship