Probability of Cancer in Pulmonary Nodules Detected on First Screening CT

This study investigated the probability that nodules detected on initial low dose CT screening are malignant by using the PanCan study as a development dataset and results from chemoprevention trials as a validation dataset.  In the two datasets, a total of 12,029 nodules were detected among 2961 pts.  144 nodules were malignant.  Among pts with nodules, 5.5% and 3.7% had cancer in the development and derivation sets.  Predictors of malignancy included older age, female sex, family history of lung cancer, emphysema, larger nodule size, upper lobe location, part solid morphology, lower nodule count, and spiculation.  Predictive ability of the model exceeded 90%.