Medical AI for Early Detection of Lung Cancer: A Survey

Authors: Guohui Cai, Ying Cai*, Zeyu Zhang, Yuanzhouhan Cao, Lin Wu, Daji Ergu, Zhinbin Liao, Yang Zhao

*Corresponding author

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Abstract

Lung cancer remains one of the leading causes of morbidity and mortality worldwide, making early diagnosis critical for improving therapeutic outcomes and patient prognosis. Computer-aided diagnosis (CAD) systems, which analyze CT images, have proven effective in detecting and classifying pulmonary nodules, significantly enhancing the detection rate of early-stage lung cancer. Although traditional machine learning algorithms have been valuable, they exhibit limitations in handling complex sample data. The recent emergence of deep learning has revolutionized medical image analysis, driving substantial advancements in this field. This review focuses on recent progress in deep learning for pulmonary nodule detection, segmentation, and classification. Traditional machine learning methods, such as SVM and KNN, have shown limitations, paving the way for advanced approaches like Convolutional Neural Networks (CNN), Recurrent Neural Networks (RNN), and Generative Adversarial Networks (GAN). The integration of ensemble models and novel techniques is also discussed, emphasizing the latest developments in lung cancer diagnosis. Deep learning algorithms, combined with various analytical techniques, have markedly improved the accuracy and efficiency of pulmonary nodule analysis, surpassing traditional methods, particularly in nodule classification. Although challenges remain, continuous technological advancements are expected to further strengthen the role of deep learning in medical diagnostics, especially for early lung cancer detection and diagnosis.

Project Overview

This project focuses on the application of deep learning techniques to the detection, segmentation, and classification of pulmonary nodules in CT images, particularly for early-stage lung cancer detection. The methods leverage advanced neural networks such as Convolutional Neural Networks (CNNs), U-Nets, and their variants to improve diagnostic accuracy, reduce false positives, and enhance the overall sensitivity of Computer-Aided Diagnosis (CAD) systems.

The project is built upon two prominent datasets: LIDC-IDRI and LUNA16, both of which are publicly available and widely used in lung nodule research. By utilizing these datasets, the project aims to achieve a more comprehensive analysis of the performance of deep learning models in the medical imaging field.

Datasets

The project utilizes several key datasets that have been essential in driving advancements in lung nodule detection and diagnosis:

  • LIDC-IDRI: A large-scale dataset containing over 1,000 lung CT cases with multi-radiologist annotations. This dataset serves as the backbone for many of the studies in lung nodule detection.
  • LUNA16: Derived from LIDC-IDRI, LUNA16 focuses on nodule detection, providing 888 high-quality CT scans with standardized metrics for evaluating algorithms.
  • Additional Datasets: Datasets such as ELCAP, NSCLC, and ANODE09 are also referenced to supplement research efforts.

Key Techniques and Models

This project explores multiple deep learning models tailored to different aspects of lung nodule detection, segmentation, and classification:

Detection Models

  • CNN-based detection: A variety of CNN architectures are used, ranging from lightweight models like Light CNN to more advanced networks such as U-Net++ and EfficientNet.
  • YOLOv8: A real-time detection model, effective for fast nodule identification with minimal false positives.
  • Hybrid Approaches: Fusion of 3D imaging techniques and biomarker data to enhance detection precision.

Segmentation Models

  • U-Net Variants: Models like Wavelet U-Net++ and 3D DenseUNet provide robust segmentation of nodules with a focus on improving Dice Similarity Coefficient (DSC).
  • Attention Mechanisms: Self-attention networks (e.g., HSNet) improve segmentation accuracy by focusing on relevant features in CT scans.
  • Multi-task Learning: Approaches that integrate both nodule detection and segmentation into a single pipeline for better performance.

Classification Models

  • Deep Learning Classifiers: CNN-based classifiers, such as those built on ResNet and DenseNet architectures, are employed to distinguish between benign and malignant nodules.
  • Ensemble Learning: Hybrid deep learning models that combine multiple classifiers to enhance accuracy, sensitivity, and specificity.
  • SVM and Traditional Approaches: For comparative purposes, traditional machine learning methods such as Support Vector Machines (SVM) are also tested against deep learning models.

Performance Metrics

The performance of the models is evaluated using the following key metrics:

  • Sensitivity (True Positive Rate): Measures the model's ability to correctly identify nodules.
  • Specificity (True Negative Rate): Measures the model's ability to correctly identify non-nodules.
  • Dice Similarity Coefficient (DSC): Used in segmentation tasks to evaluate the overlap between predicted and ground truth nodule regions.
  • Area Under the Curve (AUC): Commonly used in classification tasks to evaluate the overall model performance.
  • Competition Performance Metric (CPM): Specific to lung nodule detection, measuring sensitivity at varying false-positive rates.

Future Work

This project highlights the potential of deep learning models in improving the accuracy of lung nodule detection and classification. However, future work will focus on:

  • Improving interpretability: Developing models that can provide insights into their decision-making process.
  • Real-time applications: Enhancing the computational efficiency of models to allow for real-time diagnostic use in clinical settings.
  • Multimodal approaches: Integrating clinical data, genomic information, and imaging data to improve diagnosis accuracy.

Contributors

  • Guohui Cai: Conceptualization, Investigation, Writing – original draft
  • Ying Cai: Investigation, Writing – original draft
  • Zeyu Zhang:Writing – review & editing
  • Yuanzhouhan Cao: Methodology, Writing – review & editing
  • Lin Wu: Investigation, Methodology
  • Daji Ergu: Supervision
  • Zhibin Liao: Validation
  • Yang Zhao: Investigation, Supervision

Acknowledgements

This research has been supported by the National Natural Science Foundation of China (Grant No. 72174172) and the Scientific and Technological Innovation Team for Qinghai-Tibetan Plateau Research at Southwest Minzu University (Grant No. 2024CXTD20). We sincerely appreciate their valuable support, which made this work possible.

Key Papers