All patients receiving treatment with erlotinib monotherapy for locally advanced or metastatic NSCLC either first line in patients with an activating mutation of the receptor EGF-R or patients with stable disease after 4 cycles of standard first-line chemotherapy with platinum or after failure of at least one prior chemotherapy regimen
Age\> 18 years
Subject has signed an informed consent
Treatment initiated for at least 7 days or dosage changed for at least 7 days
You may not be if
Contraindication to the use of drug
Subject to exclusion period (as determined by a previous study or in progress)
Inability to give informed information (subject in emergency situations, difficulties in understanding the subject, ...)
Subject under judicial protection
Subject under tutorship or curatorship
Pregnancy (and woman of childbearing age without contraception)
