One hundred and nine patients with limited small cell lung carcinoma were entered in a phase II study alternating six cycles of combination chemotherapy and three courses of mediastinal radiotherapy. Chemotherapy consisted of doxorubicin 40 mg/m2 day 1, etoposide 75 mg/m2 days 1, 2, 3, cyclophosphamide 300 mg/m2 days 3, 4, 5, 6, and methotrexate 400 mg/m2 day 2 (+folinic acid rescue) or cisplatin 100 mg/m2 day 2. The total mediastinal radiation dose was 45 or 55 Gy. A 6 to 8 cycle maintenance chemotherapy followed this induction protocol. The complete remission rate at the end of the induction therapy was 79%. The local recurrence rate was 25% and the distant metastases rate was 52%. Median survival is 17.2 +/- 1.2 months and survival rate at 3 years is 26%. Lethal toxicity occurred in 3% of patients during induction therapy, and long term survivors are being evaluated. Our results justify further investigations with this alternating schedule.