Oxaliplatin has a more manageable toxicity profile than cisplatin, with no renal toxicity and a lower incidence of hematological and gastrointestinal toxicities. The combination of gemcitabine-oxaliplatin is attractive in NSCLC patients as it may improve the therapeutic index. Given the potential advantages of oxaliplatin and th finding that the addition of chemotherapy improves survival in the postoperative adjuvant setting, we conduct a phase II trial to compare adjuvant gemcitabine-oxaliplatin with gemcitabine-cisplatin in patients with completely resected stage IB, II or IIIA NSCLC

This study is a randomized phase II study. Patients are randomized to 1 of 2 treatment arms: patients receive adjuvant chemotherapy with gemcitabine-oxaliplatin or gemcitabine-cisplatin. Chemotherapy should be started within 8 weeks after complete surgical resection. Patients are followed every 3 months for 2 years, every 6 months for 3 years.

Gemcitabine-Oxaliplatin (GemOx) chemotherapy:

Gemcitabine (1,250 mg/m2)+Oxaliplatin (85 mg/m2) is given on day 1 and 15 q 4weeks. maximum 4 cycles.

Gemcitabine-Cisplatin (GemCis) chemotherapy:

Gemcitabine (1,250 mg/m2) + Cisplatin (40 mg/m2) is given on day 1 and 15 q 4weeks. maximum 4 cycles.

Inclusion Criteria:

1. Histologic diagnosis of non-small cell lung cancer.
2. Presence of pathological stage IB, II or IIIA, according to the American Joint Committee on Cancer (AJCC).
3. Completely resected tumor at NCC hospital.
4. No prior tumor therapy (radiotherapy, chemotherapy, immunotherapy, or any other type of tumor therapy).
5. Performance status of 0-1 on ECOG scale.
6. At least 18 years old
7. Patient compliance that allows adequate follow-up.
8. Adequate organ function including the following:Adequate hematologic function: WBC count ≥ 4,000/uL, absolute neutrophil count (ANC) ≥ 1,500/uL, platelet count ≥ 100,000/uL, and hemoglobin ³ 10 gm/dL.Adequate hepatic function: bilirubin ≤ 1.5 x UNL, ALT or AST ≤ 2.5 x UNL.Adequate renal function: creatinine ≤ 1.5mg/dL.
9. Signed informed consent from patient or legal representative.
10. Patients with reproductive potential must use an approved contraceptive method during and for 3 months after the study. Females with childbearing potential must have a negative urine hCG test within 7 days prior to study enrollment.

Exclusion Criteria:

1. Concurrent administration of any other tumor therapy, including radiotherapy, chemotherapy, immunotherapy.
2. Active uncontrolled infection.
3. Serious concomitant disorders that would compromise the safety of patient or compromise the patient's ability to tolerate therapy.
4. Second primary malignancy.
5. Significant neurological or mental disorder.
6. Pregnant or nursing.
7. MI within preceding 6 months or symptomatic heart disease including unstable angina, congestive heart failure, or uncontrolled arrhythmia