This is an observational prospective study that investigates only daily practice. The prescription of anti-cancer medicine is separated from the decision to include the patient in this study. In addition, the assignment of the patient to a particular therapy or therapeutic strategy is not decided in advance by this study protocol, but falls within current practice.

The patient who fulfils eligible criteria will be enrolled when starts to receive the second-line EGFR-TKI therapy. The frequency of tumor response evaluation by RECIST criteria follows the investigator's discretion as daily practice.

Inclusion Criteria:

• At least one measurable lesion according to RECIST criteria
• Histologically or cytologically confirmed NSCLC of adeno histology
• Locally progressed or metastasized on or after first-line chemotherapy. The imaging evidence of disease progression can be either chest X ray, CT or MRI assessment on measurable lesions. If no measurable lesion is available, evaluable lesions are acce

Exclusion Criteria:

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The EGFR-TKI receiver who are suitable for third-line therapy will be followed up for the regimen of the third-line anti-microtubule agents or non-anti-microtubule agents