Summary In a non-randomised study in six centres in the UK, 24 patients with previously untreated small-cell lung cancer of limited extent were treated with a regimen of alternating chemotherapy and radiotherapy to assess response, toxicity, and the feasibility of applying such a regimen on a multicentre basis in the UK. The intention was to give six courses of chemotherapy on five consecutive days at 4-week intervals: etoposide 75 mg m2 on days 1, 2, and 3; doxorubicin 40mg m2 on day 1; cisplatin 100mg m2 on day 2; and cyclophosphamide 300 mg m-2 on days 2, 3, 4 and 5. A dose of 20 Gy thoracic radiotherapy was to be given following the 2nd and the 3rd courses, and one of 15 Gy following the 4th course. After 12 patients had been admitted, the cisplatin dosage was reduced to 80 mg m-2 because of unacceptable toxicity. Two patients were withdrawn during treatment on review of their histology because their diagnosis was found to be incorrect. Only one patient of the 12 treated with cisplatin 100 mg m2 was able to complete treatment, compared with five of the eligible ten given the lower dosage. Among the 22 patients with confirmed small-cell disease, a complete response was reported in 14 (64%) and a partial response in a further three (total response rate 77%). Myelosuppression was the commonest serious adverse effect. It occurred in 19 of the 24 patients and gave rise to septicaemia in five, four of whom were receiving the higher cisplatin dose. Sixteen patients required blood transfusion and ten platelet transfusion. Vomiting, oesophagitis, and peripheral neuropathy occurred in 12, four and four patients, respectively, and radiation pneumonitis developed in two. Treatment was considered a contributory cause of death in four. The working party concluded that the alternating regimen was feasible in only a small proportion of centres in the UK, and decided not to embark on a multicentre randomised trial comparing alternating with conventional scheduling.Small-cell lung cancer responds well to combination chemotherapy (Seifter & Ihde, 1988). Objective response rates (World Health Organization, 1979) of around 80% are typical in published reports, as are median survival times of approximately 12 months in patients with limited disease and 6 months in those with extensive disease (Leonard, 1989). In patients with limited disease, the inclusion of thoracic radiotherapy in the treatment regimen both improves local control of the cancer and prolongs survival (Bleehen, 1986;Arriagada et al., 1989a). Nevertheless, 3-year survival rates are low and the great majority of patients die from their lung cancer.At the time this study was planned, however, not only high response rates but also substantial 2-year and 3-year survival rates were being reported by Arriagada and his colleagues in non-randomised phase II trials using regimens of alternating chemotherapy and radiotherapy. Thirty-five patients less than 70 years of age, with small-cell lung cancer of limited extent, and good performance status, were treated with a regim...