A Study of PC Sequential Pemetrexed Single Drug Maintenance Treatment for NSCLC and Related Predictive Biomarkers

Inclusion Criteria:

.≥65 years or PS 2

• Patients who were diagnosed by the histologic, cytologic diagnosis of IV non-small cell lung cancer
• Patients received no chemical therapy or only received targeted therapy,and there is evidence show the patent is PD

• Presence of at least one index lesion measurable by CT scan or MRI

  • leucocyte ≥ 3.5×109/L
  • neutrophil ≥ 1.5×109/L
  • platelet ≥ 80×109/L
  • Hemoglobin ≥ 9g/L
  • ALT and AST ≤ 2.5×ULN ,Tbil≤ 1.5×ULN
• BUN≤ 1.5×ULN
• Signed written informed consent

Exclusion Criteria:

• squamous carcinoma or small cell lung cancer
• Patients were allergic to pemetrexed
• Patients received chemotherapy before

• Uncontrolled acute infection

  .Uncontrolled pleural effusion

• Severe symptomatic heart disease
• Severe infection or metabolic disfunction
• Patients with other malignant tumor
• Uncontrolled brain metastases
• Patients have accepted other clinical trials

• Female patients during their pregnant and lactation period, or patients without contraception

  • Mental disorientation of disorder
  • Glucocorticoids taboo