Artificial intelligence (AI) generally describes the concept of computers emulating human intelligence. Used synonymously, machine learning (ML) is considered a subset of AI and describes the field where computers can analyze data and interact with users without explicit coding of each potential possibility. For this review, we will use the term AI, although it will generally refer to concepts of ML. In recent years, AI increasingly has been applied to medicine, oncology, and prostate cancer.1 This review will briefly touch upon 4 areas where AI and prostate cancer have overlapped: AI-driven diagnostic image analysis, AI “prediction” of prostate outcomes based on clinical data, AI prediction using multimodal data including histopathology, and AI definition of tumor and normal tissue for radiation oncology treatment planning. After describing each area, we will give practical examples of application. Finally, we will briefly discuss future applications of AI to prostate cancer.
AI-Driven Diagnostic Image Analysis and Radiomics
Image classification is an area where AI has taken large strides, driven by nonclinical work in computer vision. ML architectures such as convolutional neural networks, and newer network architectures such as transformer-based architectures, have improved the ability of AI to correctly identify elements in photographs. These models are similarly being applied to quantitative characteristics of diagnostic images (known as radiomics) for the purpose of detecting clinically significant disease.2,3 Current published ML models have shown promise but are not able to completely replace radiologist evaluation in real-world situations4; however, they may aid less experienced radiologists in distinguishing between cancerous and noncancerous lesions in prostate MRI scans.5 At the same time, some studies have shown that computer-aided detection (CAD)–assisted mammography may result in reduced sensitivity to non–CAD-identified breast lesions.6 It is possible that overreliance on AI could morph prostate cancer CAD tools from helpful assistants to a second-rate crutch.
AI Predictions of Health Outcomes
ML algorithms have been used to take clinical characteristics and genetic features and predict relevant clinical outcomes such as prostate cancer risk, presence of nodal metastases, response to therapy, and mortality.7-13 Although these ML algorithms may present predictive performance improvements compared with existing nomograms,14 their adoption in routine clinical practice likely will require automated integration into existing health care electronic medical records (EMRs), as well as navigation of regulatory frameworks. Also, obstacles to ML implementation in clinical practice include barriers to real-time data extraction and aggregation from multiple commercial EMR sources and information systems.15 In comparison, a nomogram makes clear the relative contribution of each factor to the intended clinical prediction.
AI Histopathology-Driven Characterization of Prostate Cancer
Evaluation of prostate cancer histopathology is perhaps where the most clinical impact is being made.16 One example where ML tools are helping pathologists categorize prostate cancer is Paige Prostate (Paige AI), a tool for automatically labeling prostate cancer by Gleason score.17 Another example is a multimodal deep learning network that incorporates clinical characteristics as well as features extracted from digitized histopathology to predict outcomes from treatment.18 This model was trained and evaluated in a clinical trials data set to be predictive of androgen deprivation therapy in combination with radiotherapy vs radiotherapy alone.19 Now commercialized as ArteraAI, the multimodal AI test is approved as a clinical diagnostic laboratory test by the Centers for Medicare & Medicaid Services.
AI-Driven Tumor Definition and Treatment Planning for Radiation Therapy
A rapid area of AI expansion is in aiding radiation oncologists in the automated definition of normal tissue and tumor definition. “Contouring” is the general process whereby radiation oncologists delineate organs at risk for radiation toxicity, as well as define radiation treatment targets. The definition of organs at risk and target volumes is traditionally a time-consuming and technically demanding task. AI models are improving the efficiency of this process through automated contouring and are already commercially available.20,21 These models will likely continue to improve in accuracy with recent innovations in ML architecture and multimodal imaging data.22
Once a target volume is defined, AI can improve treatment planning through improvements in efficiency and optimization of dose.23-26 These improvements in efficiency are particularly valuable for online adaptive radiotherapy, where treatment plans are adjusted daily based on time-of-treatment cross-sectional images.27
Future Applications
With the rise of generative AI in day-to-day life, patients will likely use large language model–based tools to obtain cancer treatment information. Physicians may start using AI to perform routine tasks in symptom management and patient-facing interaction.28,29 For example, the System for High-Intensity EvaLuation During Radiation Therapy (SHIELD-RT) study (NCT04277650) found that an ML algorithm accurately identified patients at high risk for needing acute care during radiotherapy. These patients were then able to benefit from random assignment to twice-weekly (vs once-weekly) clinical evaluation.30 It is likely AI will further diffuse into all aspects of health care as a supplemental aid for physicians and patients.31
Conclusion
The innovations seen in the application of AI to prostate cancer care mirror those happening throughout health care and information technology. Breakthroughs in image analysis and computer vision have diffused into the classification of prostate diagnostic imaging, pathology, and prediction of treatment outcomes. Radiation oncology has experienced improvements in practice efficiency due to AI tools. Future applications of AI for prostate cancer likely will include improved patient-facing tools.
References
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