The study will be conducted in patients with advanced NSCLC (stage IIIB-IV) who have MPE requiring therapeutic drainage, and are also eligible for treatment with chemotherapy plus bevacizumab (as defined in protocol Section 6.0). All patients will undergo placement of a Pleur-XTM catheter as part of routine practice. Eligible patients may enroll in the protocol prior to, or within 10 days following placement of their Pleur-XTM catheter. Upon enrollment, patients will be given a logsheet on which to record the volume of pleural fluid drained from their catheter. Only patients who, in the opinion of the treating physician, do not have a hemorrhagic pleural effusion (grossly bloody, or pleural fluid hemoglobin concentration > 25% of blood hemoglobin concentration) may remain on study. In addition, only patients who, in the opinion of the treating physician, have satisfactory placement of their Pleur-XTM catheter may remain on study.