This is a retrospective, multicenter and observational study of Osimertinib monotherapy treatment in Subjects with advanced or metastatic Non-Small Cell Lung Cancer (NSCLC) EGFR-T790M mutation-positive who have received the treatment within the Special Use Medication Program (SUMP) in Spain.

The study is based on the collection of data about the patients treated with Osimertinib within the Special Use medication Program. the patienes participating in this non-interventional study will not receive treatment in relation to the study.

Approximately a total of 270 patients will be included in this project from several Spanish sites. Around 52 hospitals will participate in the study. the observation period is from August 2016 to December 2018 and will include patients who started the treatment with Osimertininb from August 2016 to April 2018.

The primary objective is to estimate the progression free survival of the Osimertinib treatment.

Inclusion Criteria:

• Squamous or Non-Squamous, non-small cell lung cancer (NSCLC), Stage IIIb/IV (histologically or cytologically confirmed), EGFRm/T790M, who received osimertinib treatment within the Spanish special use medication program of Osimertinib (SUMP).
• Alive patients must have signed, dated and IRB/EC-approved written informed consent form in accordance with regulatory and institutional guidelines. This must be obtained before the performance of any protocol-related procedures that are not part of normal subject care.

Exclusion Criteria:

• Alive patients who do not want to sign and date an IRB/IEC-approved written informed consent form.
• Patients who were accepted in the SUMP, but did not receive treatment.

All patients who have received Osimertinib in the SUMP in Spain.