Methods We did a systematic review and meta-analysis using updated data on individual patients from all available randomised trials that compared radiotherapy alone with radiotherapy plus chemotherapy. Data for 3004 patients from 12 randomised controlled trials were included (11 published and one unpublished).

Findings Overall, the results showed significant prolongation of survival associated with chemotherapy, with a hazard ratio of 0.85 (95% CI 0.78-0.91, p < 0.0001) or a 15% relative decrease in the risk of death. This effect is equivalent to an absolute increase in 1-year survival of 6% (95% CI 3-9) from 40% to 46% and a 2-month increase in median survival time (1-3). There was no evidence that the effect of chemotherapy differed in any group of patients defined by age, sex, histology, performance status, or extent of resection.

Interpretation This small but clear improvement in survival from chemotherapy encourages further study of drug treatment of these tumours.