Factors Associated with a Positive Baseline Screening Exam Result in the National Lung Screening Trial

Abstract

In the National Lung Screening Trial, both patient- and center-specific factors were associated with having a positive baseline screen. Although the model does not have sufficient accuracy to provide personalized risk estimates to guide shared decision making on an individual basis, it can nonetheless inform screening centers of the likelihood of further follow-up testing for their populations at large when allocating resources. Data collected from centers as broad-based screening is implemented can be used to improve model accuracy further.

Evaluating the Patient With a Pulmonary Nodule

“…The frequency of identifying pulmonary nodules is particularly high in individuals undergoing imaging for evaluation of a known extrapulmonary malignancy, reaching 75% (233 of 308) of patients in 1 study . Other factors associated with a higher risk of a pulmonary nodule in a cohort of 26 004 individuals undergoing a baseline LDCT included a history of hard-rock mining (35.0% vs 27.3%; odds ratio [OR], 1.40 [95% CI, 1.04-1.89]), White race (28.0% vs 20.6%; OR, 1.39 [95% CI, 1.25-1.55]), residence in an area endemic for Histoplasma such as the Ohio River Valley (OR, 1.30 [95% CI, 1.21-1.40]; calculated absolute rates: 32.5% vs 26.4%), farm work (OR, 1.13 [95% CI, 1.03-1.23]; calculated absolute rates: 30.2% vs 27.1%), and a history of chronic obstructive pulmonary disease (OR, 1.08 [95% CI, 1.01-1.17], calculated absolute rates: 30.1% vs 26.8%) …”

Implementation of Lung Cancer Screening in the Veterans Health Administration

“…The reason for the overall high rate of initially positive examination results in the VHA sites is not certain but may be owing, in part, to the older age and heavier smoking history of veterans screened. 26,27 Nodule follow-up guidelines in the LCSDP included a recommendation to follow up very small nodules (<4 mm) if they were new or growing, based on results of previous scans, or had suspicious features; the NLST did not follow up nodules smaller than than 4 mm. The wide range of nodular findings among the 8 sites (range, 70 of 228 [30.7%] to 181 of 213 [85.0%]) may reflect, in part, different geographical locations 28 or differences in interpretation by participating radiologists.…”

Screening for Lung Cancer

“…A fundamental question when applying these models is whether the identification of patients for screening based on risk factors other than age and smoking history would lead to changes in patient or cancer phenotype that would affect the balance of benefit and harms of screening. The risk models include variables that affect nodule presence, 87 the risk of nodule evaluation, 88 the risk of lung cancer treatment, 89 survival after lung cancer treatment, 90 and overall survival. 91 It is thus important to pursue clinical utility studies of the application of these models in clinical practice.…”