Lung cancer, the leading cause of cancer related mortality. Among them, non small cell lung cancer accounts for 85%. Only part of patients could be treated with radical surgery, and some patients were unfit for surgery due to the poor cardio-pulmonary function or refuse surgery. For those patients, microwave ablation (MWA) could be an alternative treatment. Several small sample retrospective studies verified that MWA could be an efficacy and safe treatment.

Patients with stage I non small cell lung cancer unfit for or refused surgery will be treated with MWA in the primary tumor sites.

Inclusion Criteria:

1. Patient has a histologically or cytologically verified NSCLC,
2. The tumors small enough to treat (usually <4 cm), and without chest pleura invasion.
3. Clinical stage I NSCLC with no other sites of disease,.
4. Patient is not a candidate for surgical removal of the cancer, or refused surgery.
5. Patient is not a candidate for radiation therapy, or refused radiation therapy.
6. Patient has > 6 month life expectancy.
7. Eastern Cooperative Oncology Group performance status of 0 to 2.
8. No prior anticancer treatments including surgery, radiation,chemotherapy or local treatments.
9. Sufficient organ functions.
10. Written informed consent.

Exclusion Criteria:

1. Active bacterial or fungous infection.
2. Simultaneous or metachronous (within the past 5 years) double cancers.
3. Women during pregnancy or breast-feeding.
4. Interstitial pneumonitis, pulmonary fibrosis, or severe pulmonary emphysema.
5. Uncontrollable diabetes mellitus.
6. History of severe heart disease, heart failure, myocardial infarction within the past 6 months or attack of angina pectoris within the past 6 months.