SDAE-GAN: Enable high-dimensional pathological images in liver cancer survival prediction with a policy gradient based data augmentation method.

High-dimensional pathological images produced by Immunohistochemistry (IHC) methods consist of many pathological indexes, which play critical roles in cancer treatment planning. However, these indexes currently cannot be utilized in survival prediction because joining them with patients' clinicopathological features (e.g., age and tumor size) is challenging due to their high dimension and sparse features. To address this problem, we propose a novel two-stage survival prediction model named ICSPM to join the IHC images and clinicopathological features. For the first stage, our proposed SDAE-GAN compresses high-dimensional IHC images to flat, compact and representative feature vectors by compressing and reconstructing them. For the first time, SDAE-GAN integrates dense blocks, the stacked auto-encoder and the GAN architecture to maximize the ability to detect patterns in IHC images. In addition, we propose a novel policy gradient based data augmentation method to involve the diversity in IHC images without breaking patterns inside them. For the second stage, ICSPM adopts a DenseNet to join feature vectors and clinicopathological features for survival prediction. Experimental results demonstrate that ICSPM reached a state-of-the-art prediction accuracy of 0.72 on the five-year survival. ICSPM is the first work to enable high-dimensional IHC images in cancer survival prediction. We prove that high-dimensional IHC images and clinicopathological features provide valuable and complementary information in survival prediction.