PEPITA Study: An Observational Study of Tarceva (Erlotinib) in Second Line in Patients With Locally Advanced or Metastatic Squamous Non-Small Cell Lung Cancer

Inclusion Criteria: * Adult patients, \>/= 18 years of age * Histologically or cytologically confirmed advanced (Stage IIIB) or metastatic (Stage IV) squamous non-small cell lung cancer after failure of first-line platinum-based chemotherapy * Patients for whom the treating physician has decided to initiate treatment with Tarceva Exclusion Criteria: * Mixed non-small cell and small-cell lung carcinoma or mixed squamous cell carcinoma with predominant adenocarcinoma component * Current participation in a clinical trial evaluating an anticancer treatment