Paraneoplastic suspect lung cancer

Hi, fascinating subject of paraneoplastic syndromes. Patient has low sodium and fatigue going on two years. Suspected paraneoplasic syndrome and underlying small cell lung cancer. Followed patient 18 months with CT chest/abdomen. Finally ordered PET/CT which came back with no suspicions. What would be your next move?
Source: Student Doctor Network - Category: Universities & Medical Training Authors: Source Type: forums