Trial of Pemetrexed or Pemetrexed With Gemcitabine for Patients With Advanced Lung Cancer Who Are Not Eligible for Platinum-Based Chemotherapy and Have Not Previously Been Treated With Chemotherapy

This study is for elderly patients who haven't been given prior chemotherapy or for patients who cannot be treated with platinum based chemotherapy. The patients who are eligible for this study will have been diagnosed with advanced or metastatic non-small cell lung cancer. The patients will be randomly assigned to one of two treatment options: single agent pemetrexed or single agent pemetrexed with single agent gemcitabine following right after the pemetrexed treatment.