Clinical Research of S-1 Versus Pemetrexed in the Maintenance Treatment of Advanced NSNSCLC

Inclusion Criteria:

1. Written informed consent
2. Histological or cytological documented
3. NSCLC of stage IIIB (surgery is unacceptable) or IV confirmed by mediastinoscopy or PET based on RECIST1.1.
4. Candidates have been accepted 4-6 cycles of gemcitabine/carboplatin Naive chemotherapy, and evaluated as CR,PR or SD.
5. Candidates's expected survival time should be greater than or equal to 3 months with ECOG performance status 0-1, adequate haematological and Hepatic- renal function, and cardiac function.
6. At least one measurable tumor lesion (maximum diameter has to be greater than 10mm scan by CT or MRI) or malignant lymph node (15mm in short axis), and must not be accepted radiotherapy.
7. No any other following malignancy or any serious complication caused by metastatic encephaloma.
8. No any gastrointestinal diseases that could reduce the drug absorption.
9. Female: Candidates who have any chance to be pregnant must accept pregnancy tests 72 hours before therapy, and take medical allowed contraceptives during therapy or in 3 mouths after therapy. Pregnancy tests results must be negative.Lactation female are not included.
10. Male: Be sterilized or take contraceptives during therapy or in 3 mouths after therapy.

Exclusion Criteria:

1. Any unstable systemic disease
2. Patients with exposure to any recent anticancer therapy outside of this trial.
3. Pregnant or breast-feeding women