Potentially Curative Radiotherapy for Non–Small-Cell Lung Cancer in Norway: A Population-Based Study of Survival

Abstract

The efficacy of curative irradiation in the treatment of non-small-cell lung cancer patients is considered limited. The purpose of this study was to evaluate long-term survival in a population-based approach. Cases of non-small-cell lung cancer diagnosed from 1993 to 2001 were identified in the Cancer Registry of Norway. Electronic linkage with national data from the hospitals' radiotherapy verification systems identified those who received potentially curative doses (≥ 50 Gy). Hospital records were reviewed for all patients. A total of 497 patients (336 men) were identified with a radiation dose of ≥ 50 Gy delivered to the lung region. Of these, 41% received 60 Gy or more. The majority (70%) of patients included had advanced stage disease: 24% Stage IIIA and 46% Stage IIIB. The overall 1-, 3-, and 5-year observed survival rates were 53%, 16%, and 9%, respectively. Multivariable analyses identified stage and chemotherapy, but not radiation dose, as significant independent prognostic variables for survival. However, 68% of patients treated with chemotherapy participated in prospective studies with inclusion criteria that excluded patients with less favorable prognostic factors, leading to a selection bias. The number of fractions and the radiation doses varied widely among different hospitals. The long-term prognosis after radiation therapy is poor. More sophisticated, targeted, and uniform delivery of radiation therapy is needed. The apparent benefit of chemotherapy may in part be due to selection of patients with more favorable prognostic factors for this therapy.