- Histological or cytological confirmation of extensive small cell lung cancer. For this study, extensive stage disease will be defined as including those patients whose disease cannot be encompassed in a curative radiation field. While this definition varies by treating center, it will include patients with metastatic disease to contralateral lung parenchyma or other organs (e.g. liver) and may include patients with contralateral supraclavicular, mediastinal, or hilar lymph nodes or a pleural effusion.