A Study on the Correlation Between Tarceva (Erlotinib) - Induced Rash and Efficacy in EGFR Mutated Participants With Advanced Non-Small Cell Lung Cancer Receiving First-Line Therapy

Inclusion Criteria: * Adult participants, \>/= 18 years of age * Inoperable, locally advanced, recurrent or metastatic (Stage IIIB or IV) non-small cell lung cancer (NSCLC) * Presence of epidermal growth factor receptor (EGFR) mutations * Previously untreated with any systemic anti-neoplastic therapy for advanced disease * Last dose of a prior systemic anti-neoplastic therapy for early-stage disease \>/= 4 weeks before study start, and patient recovered from acute toxicities of any previous therapy * A life expectancy of at least 12 weeks * Able to comply with the study and its follow-up procedures * Female participants had to be postmenopausal (24 months of amenorrhea), surgically sterile or agree to use a physical method of contraception. Male participants had to be surgically sterile or agree to use a barrier method of contraception. Women with an intact uterus (unless amenorrhoeic for the last 24 months) had to have a negative pregnancy test (urine or serum) within 3 days prior to erlotinib treatment initiation in the study. Male and female participants had to use effective contraception during the study and for a period of 90 days following the last administration of erlotinib. Acceptable methods of contraception included an established hormonal therapy or intrauterine device for females, and the use of a barrier contraceptive (i.e. diaphragm or condoms) Exclusion Criteria: * Pregnant or breast feeding women * Granulocyte count \<1.5 x 109/L and platelet count \<100\*10\^9/L * Serum bilirubin \>1.5 upper limit of normal (ULN) * Aspartate aminotransferase (AST) and/or alanine aminotransferase (ALT) \> 2 \* ULN (or \>5 \* ULN if clearly attributable to liver metastasis) * Serum creatinine \>1.5 ULN or creatinine clearance \<60 mL/min * Known allergy or other adverse reaction to study drug or any other related compound * Any significant unstable systemic disease (including active infection, grade 4 hypertension, unstable angina, congestive heart failure, hepatic, renal or metabolic disease) * Prior systemic anti-neoplastic therapy with HER1/EGFR inhibitors (as small molecule or monoclonal antibody therapy) * Newly diagnosed or not yet definitively treated (i.e. stable disease \>/= 2 months) CNS metastases or spinal cord compression * Any significant ophthalmological abnormality, especially those likely to increase the risk of corneal epithelial lesions (the use of contact lenses is not recommended during the study) * Participants who could not take oral medication, who required intravenous alimentation, had had prior surgical procedures affecting absorption, or had active peptic ulcer disease * Active cancer other than NSCLC, except for basal cell or squamous cell carcinomas of the skin that have been excised and cured