Estimate of lung cancer mortality from low-dose spiral computed tomography screening trials: implications for current mass screening recommendations.

Abstract

Low-dose computed tomography (CT) has been suggested for lung cancer screening. Several observational trials have published their preliminary results, and some investigators suggest that this technique will save lives. There are no mortality statistics, however, and the current study used published data from these trials to estimate the disease-specific mortality in this high-risk population. Two nonrandomized CT screening trials were selected from the literature for analysis. The number of trial participants, the number of lung cancers diagnosed per year, and stage distribution of the cancers was recorded. Previously published 5-year survival data were used to calculate the number of predicted lung cancer deaths and estimate the overall lung cancer mortality per 1,000 person-years among participants screened. These statistics were then compared to the previous Mayo Lung Project, which used chest radiographs and sputum cytology for screening high-risk individuals. This study estimates the lung cancer mortality is 4.1 deaths per 1,000 person-years in the Mayo Clinic CT screening trial, and is 5.5 deaths per 1,000 person-years in the Early Lung Cancer Action Program trial. These data are similar to the lung cancer mortality of 4.4 deaths per 1,000 person-years in the interventional arm, and 3.9 deaths per 1,000 person-years in the usual-care arm of the previous Mayo Lung Project. These data suggest that CT screening could produce similar outcomes to prior chest radiographic trials in this high-risk group. Results from randomized trials are required, however, before the true utility of mass screening with CT for lung cancer can be determined.