Abstract
To validate and compare published prognostic classifications for predicting survival of patients with small cell lung cancer.
We pooled data from phase III randomised clinical trials and used Cox models for validation purposes and concordance probability estimates for assessing predictive ability.
We included 693 pts. All the classifications impacted significantly survival with hazard ratios (HR) in the range 1.57–1.68 (all p<0.0001). Median survival times were for the best predicted groups from 16 to 19 months while from 6 to 7 months for the poorest groups. Most of the paired comparisons were also statistically significant. We obtained similar results when restricting the analysis to patients with extensive disease. Multivariate Cox models for fitting survival data were also published. The HRs for a single covariate derived them were : 8.23 (95% CI : 5.88–11.69), 9.46 (6.67–13.50) and, for extensive disease : 5.60 (3.13–9.93), 12.49 (5.57–28.01) and 8.83 (4.66–16.64). Concordance probability estimates ranged from 0.55 to 0.65 (overlapping confidence intervals).
Published classifications are validated and suitable for use at a population level. Expectedly, prediction at an individual level remains problematic. A specific model designed for extensive disease patients does not appear to perform better.
- ERS