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Thorax. 2019 Jul;74(7):643-649. doi: 10.1136/thoraxjnl-2018-212638. Epub 2019 Mar 12.

Feasibility of lung cancer prediction from low-dose CT scan and smoking factors using causal models.

Author information

1
Department of Computational and Systems Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
2
Department of Computer Science, University of Pittsburgh, Pittsburgh, Pennsylvania, United States.
3
Department of Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States.
4
Current affiliation: Department of Respiratory Medicine, Chinese PLA General Hospital, Beijing, China.
5
Division of Cancer Control and Population Sciences, UPMC Hillman Cancer Center, Pittsburgh, Pennsylvania, United States.
6
Division of Hematology, Oncology, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States.
7
Department of Epidemiology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States.
8
Department of Computational and Systems Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA benos@pitt.edu.
9
Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States.

Abstract

INTRODUCTION:

Low-dose CT (LDCT) is currently used in lung cancer screening of high-risk populations for early lung cancer diagnosis. However, 96% of individuals with detected nodules are false positives.

METHODS:

In order to develop an efficient early lung cancer predictor from clinical, demographic and LDCT features, we studied a total of 218 subjects with lung cancer or benign nodules. Probabilistic graphical models (PGMs) were used to integrate demographics, clinical data and LDCT features from 92 subjects (training cohort) from the Pittsburgh Lung Screening Study cohort.

RESULTS:

Learnt PGMs identified three variables directly (causally) linked to malignant nodules and the largest benign nodule and used them to build the Lung Cancer Causal Model (LCCM), which was validated in a separate cohort of 126 subjects. Nodule and vessel numbers and years since the subject quit smoking were sufficient to discriminate malignant from benign nodules. Comparison with existing predictors in the training and validation cohorts showed that (1) incorporating LDCT scan features greatly enhances predictive accuracy; and (2) LCCM improves cancer detection over existing methods, including the Brock parsimonious model (p<0.001). Notably, the number of surrounding vessels, a feature not previously used in predictive models, significantly improves predictive efficiency. Based on the validation cohort results, LCCM is able to identify 30% of the benign nodules without risk of misclassifying cancer nodules.

DISCUSSION:

LCCM shows promise as a lung cancer predictor as it is significantly improved over existing models. Validated in a larger, prospective study, it may help reduce unnecessary follow-up visits and procedures.

KEYWORDS:

cancer screening; low-dose CT; lung cancer risk

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