Failure-specific prognostic factors after continuous hyperfractionated accelerated radiotherapy (CHART) or conventional radiotherapy in locally advanced non-small-cell lung cancer: a competing risks analysis.

The aim of this study was to identify possible failure-specific prognostic factors in non-small-cell lung cancer. Clinical outcome was analysed in 549 patients participating in the randomized controlled trial of CHART vs conventional radiotherapy. Local failure and distant failure with or without concurrent local relapse were subjected to a competing risk analysis using an accelerated failure-time model with a log-logistic hazard function. Randomization to CHART (2 P = 0.005), increasing age (2 P = 0.036) and female sex (2 P = 0.09) was all associated with a prolonged interval to failure. Advanced clinical stage was associated with a decreased interval to failure (2 P = 0.004) and a significantly increased risk (2 P = 0.009) of failing in distant rather than in local position. From this model, prognostic indices for local and distant failure were estimated for each individual patient. Competing risk analysis allows identification of patients with different failure patterns, and may provide a means of stratifying patients for intensified local or systemic therapy.