To evaluate the effectiveness of alternating or sequential schedules of cyclophosphamide, doxorubicin, and etoposide (CDE) chemotherapy and irradiation in patients with previously untreated small-cell lung cancer (SCLC).

A total of 335 eligible patients were randomized between five courses of CDE chemotherapy followed by thoracic irradiation 50 Gy in 20 daily fractions (S) and the same total dose of chemotherapy and irradiation split into four courses of five daily fractions delivered on days 14 to 21 of the second and subsequent chemotherapy courses (A). Patients had a median age of 61 years (range, 33 to 75); 224 (66%) were male; the Eastern Cooperative Oncology Group (ECOG) performance status (PS) was 0 or 1 in 311; and 254 had weight loss less than 10%.

The overall median survival duration was 15 months, with 62% (95% confidence interval [CI], 57% to 67%) 1-year, 25% (95% CI, 20% to 30%) 2-year, and 14% (95% CI, 10% to 18%) 3-year survival rates. There was no significant difference between the arms. The median survival time was 14 months in A and 15 months in S. One-year survival was 60% in A (95% CI, 53% to 67%) and 64% in S (95% CI, 57% to 71%); 2-year survival was 26% in A (95% CI, 19% to 33%) and 23% in S (95% CI, 16% to 30%); and 3-year survival was 12% in A (95% CI, 6% to 18%) and 15% in S (95% CI, 9% to 21%). World Health Organization (WHO) grade 3 and 4 neutropenia occurred in 90% of A and 77% of S patients (P < .001) and WHO grade 3 and 4 thrombocytopenia in 33% of A and 20% of S patients (P < .001). Rates of other acute and late toxicities were similar in both arms. Hematologic toxicity compromised treatment dose delivery; less than 50% of A patients received greater than 95% of prescribed chemotherapy and 77% their full radiation course, compared with 60% and 93% for arm S (P < .009). Local relapse was the site of first failure in 60% of all patients and 75% of these suffered an in-field relapse; no difference could be seen between the two arms.

This trial failed to confirm the superiority of an alternating schedule of delivery. For this combination of chemotherapy and irradiation, hematologic toxicity compromised treatment delivery and could have contributed to the overall result. The poor rates of local control are disappointing and require intensification of the radiation therapy strategy.