Would you treat a patient with small cell lung cancer (limited to lung and mediastinum) but also with a malignant pleural effusion with upfront definitive thoracic chemoradiation?  

I would treat such a case as EXTENSIVE DISEASE.  That means chemotherapy with 4 cycles of Plat/Etop, and restage with PET.  If the pleural disease has gone by imaging or/and pleural tap, I would add thoracic radiotherapy 30 gy/10 fractions and PCI 2.5 gy X ten. If the pleural space remains...

We would not treat like limited stage but this is subset of extensive stage if have nice response to chemo would add thoracic RT with PCI