The effect of radiotherapy on the survival of non-small cell lung cancer patients.

Abstract

To determine if thoracic radiotherapy improves the survival of non-small cell lung cancer (NSCLC) patients. A Cox proportional hazards model with prognostic and treatment covariates was estimated using prospective data for 129 NSCLC patients presenting at the Victoria Clinic (ViCC) of the British Columbia Cancer Agency (BCCA) 1990-1991. The estimated model was simulated to predict survival curves for groups of patients with and without treatment. The difference between the predicted median survival with treatment and without treatment is the gain in survival attributable to treatment. After adjusting for the effect of TNM staging, Karnofsky performance status, weight loss, tumor size, and tumor histology on survival, high-dose palliative radiotherapy (RT) (30-50 Gy in 10-20 fractions) increased median survival by 79 days (95% confidence interval: 31-106 days), and lowered the relative risk of death rate to 0.53 (95% confidence interval: 0.35-0.85). Radical RT (50 or more Gy, in 20 or more fractions) increased median survival by 424 days (95% confidence interval: 302-488 days), and lowered the relative risk of death to 0.24 (95% confidence interval: 0.14-0.43). Our results support the hypothesis that the increased survival of patients receiving aggressive palliative, or radical, RT is due not solely to patient selection, but also partly to a response to treatment.