Chemotherapy was initiated. The patient's performance status deteriorated significantly. Her ECOG score was 4. Three months after initiating treatment she complained of increasing shortness of breath and fatigue interfering with activities of daily living. Her chest radiograph showed a large right-sided pleural effusion. Thoracentesis removed 1 liter of serosanguinous fluid. The patient's dyspnea improved and she requested additional treatment. The lung was fully expanded on the post-procedure chest radiograph. Cytology was positive for adenocarcinoma, consistent with the lung primary. In view of evidence for progressive disease, pleural fluid was sent for molecular analysis.