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[Prognosis Prediction of Lung Cancer Patients Using CT Images: Feature Extraction by Convolutional Neural Network and Prediction by Machine Learning].

PURPOSE
Lung cancer accounts for the largest number of deaths among malignant tumors. Recently, more and more patients are concerned about their own life expectancy. CT examination is essential for the diagnosis of lung cancer. However, it is difficult to accurately predict the prognosis using CT images. In this study, we developed a method to predict the prognosis of lung cancer patients from CT images using a convolutional neural network (CNN) and a machine learning method.


METHODS
In this study, the CT images of 173 lung cancer patients were collected. First, we selected the slice with the largest tumor size in each case and extracted features using a CNN. Next, we performed feature selection using information gain and predicted alive or death by classifiers. An artificial neural network or Naïve Bayes was used as a classifier and alive and death were predicted at one-year intervals from one year to five years later.


RESULTS
We evaluated the prediction accuracy via the three-fold cross-validation method and found that the prediction accuracies were around 80% for all periods from 1 to 5 years. In the evaluation of the survival curve, the shape of the curve was close to the actual curve.


CONCLUSION
These results indicate that feature extraction by a CNN and classification by the machine learning method may be effective in predicting the prognosis of lung cancer patients using CT images.