Development of nasopharyngeal carcinoma target delineation: from two-dimensional radiotherapy to adaptive precision radiotherapy

Nasopharyngeal carcinoma (NPC) is mainly treated with radiotherapy. With the advancements of imaging and radiotherapy techniques, the delineation of NPC target areas has evolved from empirical field setting in the two-dimensional era to three-dimensional conformal radiotherapy (3D-CRT), intensity modulated radiotherapy (IMRT), and image-guided adaptive radiotherapy (ART), significantly improving treatment accuracy and safety. This review systematically explores the development process of target area delineation in NPC, focusing on the evolution and standardization of target areas in the nasopharynx and neck lymph nodes, and combines the role of multimodal imaging such as MRI and PET-CT in target area delineation. The article further examines the clinical response strategies and research trends of target area changes after induction chemotherapy (IC), and looks forward to the potential of ART and artificial intelligence in future target area delineation. The review aims to provide clinical practitioners with a scientific, rational, and personalized approach to target delineation, optimizing treatment plans and improving clinical outcomes.