THE EFFECT OF RADIOTHERAPY ON THE SURVIVAL OF NONSMALL CELL LUNG-CANCER PATIENTS

Purpose: To determine if thoracic radiotherapy improves the survival o f non-small cell lung cancer (NSCLC) patients. Methods and Materials: A Cox proportional hazards model with prognostic and treatment covaria tes was estimated using prospective data for 129 NSCLC patients presen ting at the Victoria Clinic (ViCC) of the British Columbia Cancer Agen cy (BCCA) 1990-1991. The estimated model was simulated to predict surv ival curves for groups of patients with and without treatment. The dif ference between the predicted median survival with treatment and witho ut treatment is the gain in survival attributable to treatment. Result s: After adjusting for the effect of TNM staging, Karnofsky performanc e status, weight loss, tumor size, and tumor histology on survival, hi gh-dose palliative radiotherapy (RT) (30-50 Gy in 10-20 fractions) inc reased median survival by 79 days (95% confidence interval: 31-106 day s), and lowered the relative risk of death rate to 0.53 (95% confidenc e interval: 0.35-0.85). Radical RT (50 or more Gy, in 20 or more fract ions) increased median survival by 424 days (95% confidence interval: 302-488 days), and lowered the relative risk of death to 0.24 (95% con fidence interval: 0.14-0.43). Conclusion: Our results support the hypo thesis that the increased survival of patients receiving aggressive pa lliative, or radical, RT is due not solely to patient selection, but a lso partly to a response to treatment. (C) 1998 Elsevier Science Inc.