CLINATEZO cohort will evaluate overall survival, real world progression-free survival, best response and duration of treatment in patients with advanced, metastatic Small Cell Lung Cancer (SCLC) who received atezolizumab combined with chemotherapy part of the French Early Access Program (ATU). Subsequent treatments (treatment delivered immediately after treatment with atezolizumab and chemotherapy) will be recorded. Those outcomes will be correlated to clinical, pathological, and radiological characteristics of patients.

Standard-of-care first-line treatment for advanced, metastatic Small Cell Lung Cancer is platinum chemotherapy (carboplatin or cisplatin) with etoposide. Despite response rates of 60 to 65%, limited progress has been made in more than two decades; outcomes remain poor, with a median overall survival of approximately 10 months. Small cell lung cancer has a high mutation burden, which suggests that these tumors may be immunogenic and could respond to immune-checkpoint inhibitors.

Atezolizumab is a humanized monoclonal anti-programmed death ligand 1 (PD-L1) antibody that inhibits PD-L1-programmed death 1 (PD-1) and PD-L1-B7-1 signaling and restores tumor-specific T-cell immunity.

The addition of atezolizumab to chemotherapy in the first-line treatment of advanced, metastatic Small Cell Lung Cancer has been granted access for patients in France part of an Early access program (ATU), in May 2019.

Inclusion Criteria:

• Patients with histologically or cytologically confirmed extensive stage Small Cell Lung Cancer at time of initiation of treatment with atezolizumab and chemotherapy.
• Patients who were informed about the study and accepted for their data to be collected.
• Patients who received at least one dose of treatment with atezolizumab and chemotherapy as part of the French Early Access Program (ATU program) and have been accepted within this ATU program
• Selection period spans from May 6th 2019 until January 31st 2020 for initiation of treatment with atezolizumab and chemotherapy.

Exclusion Criteria:

• Patients enrolled in a clinical trial assessing treatment with a combination of atezolizumab and chemotherapy. (ATU was granted to patients unable to meet eligibility criteria for on-going recruiting trials, unable to participate to other clinical trials, or because other medical interventions were not considered appropriate or acceptable).
• Patients who were included in the French Early Access Program (ATU program) but did not receive any atezolizumab and chemotherapy treatment.

Patients with histologically or cytologically confirmed extensive stage Small Cell Lung Cancer at time of initiation of treatment with atezolizumab and chemotherapy