BACKGROUND Major issues in the implementation of screening for lung cancer by means of low-dose computed tomography (CT) are the definition of a positive result and the management of lung nodules detected on the scans. We conducted a population-based prospective study to determine factors predicting the probability that lung nodules detected on the first screening low-dose CT scans are malignant or will be found to be malignant on follow-up. METHODS We analyzed data from two cohorts of participants undergoing low-dose CT screening. The development data set included participants in the Pan-Canadian Early Detection of Lung Cancer Study (PanCan). The validation data set included participants involved in chemoprevention trials at the British Columbia Cancer Agency (BCCA), sponsored by the U.S. National Cancer Institute. The final outcomes of all nodules of any size that were detected on baseline low-dose CT scans were tracked. Parsimonious and fuller multivariable logistic-regression models were prepared to estimate the probability of lung cancer. RESULTS In the PanCan data set, 1871 persons had 7008 nodules, of which 102 were malignant, and in the BCCA data set, 1090 persons had 5021 nodules, of which 42 were malignant. Among persons with nodules, the rates of cancer in the two data sets were 5.5% and 3.7%, respectively. Predictors of cancer in the model included older age, female sex, family history of lung cancer, emphysema, larger nodule size, location of the nodule in the upper lobe, part-solid nodule type, lower nodule count, and spiculation. Our final parsimonious and full models showed excellent discrimination and calibration, with areas under the receiver-operating-characteristic curve of more than 0.90, even for nodules that were 10 mm or smaller in the validation set. CONCLUSIONS Predictive tools based on patient and nodule characteristics can be used to accurately estimate the probability that lung nodules detected on baseline screening low-dose CT scans are malignant. (Funded by the Terry Fox Research Institute and others; ClinicalTrials.gov number, NCT00751660.)

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Objective:To determine the inter-observer agreement on triage assignment by first-time users with diverse training and background using the Canadian Emergency Department Triage and Acuity Scale (CTAS).Methods:Twenty emergency care providers (5 physicians, 5 nurses, 5 Basic Life Support paramedics and 5 Advanced Life Support paramedics) at a large urban teaching hospital participated in the study. Observers used the 5-level CTAS to independently assign triage levels for 42 case scenarios abstracted from actual emergency department patient presentations. Case scenarios consisted of vital signs, mode of arrival, presenting complaint and verbatim triage nursing notes. Participants were not given any specific training on the scale, although a detailed one-page summary was included with each questionnaire. Kappa values with quadratic weights were used to measure agreement for the study group as a whole and for each profession.Results:For the 41 case scenarios analyzed, the overall agreement was significant (quadratic-weighted κ = 0.77, 95% confidence interval, 0.76–0.78). For all observers, modal agreement within one triage level was 94.9%. Exact modal agreement was 63.4%. Agreement varied by triage level and was highest for Level I (most urgent). A reasonably high level of intra- and inter-professional agreement was also seen.Conclusions:Despite minimal experience with the CTAS, inter-observer agreement among emergency care providers with different backgrounds was significant.

Non-lung cancer outcomes drive screening efficiency in diverse, tobacco-exposed populations. Use of risk selection can reduce the budget impact, and screening may even offer cost savings if noncurative treatment costs continue to rise.