Boosting Advanced Nasopharyngeal Carcinoma Stage Prediction Using a Two-Stage Classification Framework Based on Deep Learning

Nasopharyngeal carcinoma (NPC) is a popular malignant tumor of the head and neck which is endemic in the world, more than 75% of the NPC patients suffer from locoregionally advanced nasopharyngeal carcinoma (LA-NPC). The survival quality of these patients depends on the reliable prediction of NPC stages III and IVa. In this paper, we propose a two-stage framework to produce the classification probabilities for predicting NPC stages III and IVa. The preprocessing of MR images enhance the quality of images for further analysis. In stage one transfer learning is used to improve the classification effectiveness and the efficiency of CNN models training with limited images. Then in stage two the output of these models are aggregates using soft voting to boost the final prediction. The experimental results show the preprocessing is quite effective, the performance of transfer learning models perform better than the basic CNN model, and our ensemble model outperforms the single model as well as traditional methods, including the TNM staging system and the Radiomics method. Finally, the prediction accuracy boosted by the framework is, respectively, 0.81, indicating that our method achieves the SOTA effectiveness for LA-NPC stage prediction. In addition, the heatmaps generated with Class Activation Map technique illustrate the interpretability of the CNN models, and show their capability of assisting clinicians in medical diagnosis and follow-up treatment by producing discriminative regions related to NPC in the MR images. Graphic Abstract