Inclusion Criteria: Cohort 1 and 2: - Patients 18 years of age or older at SCLC diagnosis - Confirmed diagnosis of SCLC within the patient identification period (between October 2013 and October 2015) - Initiated on first-line treatment (radiotherapy and/or chemotherapy) for their SCLC - Full oncology medical history for the mandatory variables of the study available in the participating center from day of diagnosis until the end of follow-up or death (whichever occurs first) - Signed informed consent (where required as per local requirements) Cohort 3: - Patients 18 years of age or older at SCLC diagnosis - Confirmed diagnosis of SCLC not earlier than October 2013 - Initiated on second-line treatment due to relapse after first-line therapy not later than August 2016 - Full oncology medical history for the mandatory variables of the study available in the participating center from day of diagnosis until the end of follow-up or death (whichever occurs first) - Signed informed consent (where required as per local requirements) Exclusion Criteria: - Participants with previous malignancies (except non-melanoma skin cancers, and in situ cancers such as the following: bladder, gastric, colon, cervical/dysplasia, melanoma, or breast) are excluded unless a complete remission was achieved at least 2 years prior to first treatment and no additional therapy is required or anticipated to be required during the study period. Other Inclusion/Exclusion criteria may apply