To estimate the impact of chemotherapy on survival of patients with advanced non-small-cell lung cancer (NSCLC).
Randomized controlled trials (RCTs) published in the English-language medical literature between 1970 and 1991 were identified through MEDLINE and the reference lists of relevant articles. Six RCTs that accounted for 635 patients and compared first-line chemotherapy with supportive care in advanced NSCLC and reported survival up to at least 1 year were identified. Cumulative proportions of survival at 3, 6, 9, and 12 months for chemotherapy and control groups were derived from survival curves.
Within each study, the effect of chemotherapy was estimated with a pooled relative risk (RR) across the four 3-month periods. An overall estimate of the RR of death at 1 year (RRM-H) was then calculated and a survival curve for chemotherapy-treated patients was constructed applying the pooled estimate of the RR (RRW) for each 3-month period. Overall, chemotherapy was associated with a 24% (95% confidence interval [CI], 13% to 34%) reduction in the probability of death when compared with supportive care. However, the effect of treatment appeared to decrease significantly after the first 6 months from therapy inception and the mean potential gain in survival, as compared with supportive care, was approximately 6 weeks (95% CI, 1 to 10).
Chemotherapy is effective in the treatment of advanced NSCLC, but its impact on the length of survival is limited. Future RCTs should still include an untreated control group and should measure quality of life in addition to survival.