 To determine whether administering high dose thoracic radiotherapy, 70 Gy 2 Gy once-daily over 7 weeks or 61.2 Gy 1.8 Gy once-daily for 16 days followed by 1.8 Gy twice-daily for 9 days, will improve median and 2-year survival compared with 45 Gy 1.5 Gy twice-daily over 3 weeks in patients with limited stage small cell lung cancer. 