Early Compared with Late Radiotherapy in Combined Modality Treatment for Limited Disease Small-cell Lung Cancer: a London Lung Cancer Group Multicenter Randomized Clinical Trial and Meta-analysis

Purpose: To replicate an earlier National Cancer Institute of Canada (NCIC) trial that examined the effect on survival of the timing of thoracic radiotherapy (TRT) in patients with limited disease small-cell lung cancer (SCLC).

Patients And Methods: Patients received three cycles of cyclophosphamide, doxorubicin, and vincristine alternating with three cycles of etoposide and cisplatin. Three hundred twenty five chemotherapy- and radiotherapy-naïve patients were randomly assigned to either early TRT administered concurrently in the second cycle or late TRT administered concurrently with the sixth cycle; the dose was 40 Gy in 15 fractions over 3 weeks.

Results: TRT was received by 92% and 82% of patients in the early and late arms, respectively (P = .01). Sixty-nine percent of patients in the early arm received all six courses of chemotherapy compared with 80% in the late arm (P = .003). There was no evidence of a survival difference; median overall survival time was 13.7 and 15.1 months in the early and late arms, respectively (P = .23). In a meta-analysis of all eight trials that compared early and late TRT, there were three in which the proportion of patients who completed their planned chemotherapy was similar between the TRT arms (hazard ratio [HR] = 0.73; 95% CI, 0.62 to 0.86) and five in which proportionally fewer patients in the early TRT arm completed their chemotherapy (HR = 1.06; 95% CI, 0.97 to 1.17).

Conclusion: This study failed to show a survival advantage for early TRT with chemotherapy in limited-stage SCLC, unlike the NCIC trial. However, the results of a meta-analysis suggest that it is essential to ensure that the delivery of chemotherapy is optimal when administered with early TRT.