Owing to improvements in our understanding of the biological principles of tumour initiation and progression, a wide variety of novel targeted therapies have been developed. Developments in biomedical imaging, however, have not kept pace with these improvements and are still mainly designed to determine lesion size alone, which is reflected in the Response Evaluation Criteria in Solid Tumors (RECIST). Imaging approaches currently used for the evaluation of treatment responses in patients with solid tumours, therefore, often fail to detect successful responses to novel targeted agents and might even falsely suggest disease progression, a scenario known as pseudoprogression. The ability to differentiate between responders and nonresponders early in the course of treatment is essential to allowing the early adjustment of treatment regimens. Various imaging approaches targeting a single dedicated tumour feature, as described in the hallmarks of cancer, have been successful in preclinical investigations, and some have been evaluated in pilot clinical trials. However, these approaches have largely not been implemented in clinical practice. In this Review, we describe current biomedical imaging approaches used to monitor responses to treatment in patients receiving novel targeted therapies, including a summary of the most promising future approaches and how these might improve clinical practice.

由于对我们对肿瘤发生和发展的生物学原理的理解有所改善，因此已经开发了多种新颖的靶向疗法。然而，生物医学成像技术的发展并没有跟上这些改进的步伐，并且仍然主要设计为仅确定病灶的大小，这在《实体瘤反应评估标准》（RECIST）中得到了体现。因此，当前用于评估实体瘤患者治疗反应的影像学方法通常无法检测出对新型靶向药物的成功反应，甚至可能错误地提示疾病进展，即假进展。在治疗过程中早期区分反应者和非反应者的能力对于允许早期调整治疗方案至关重要。如癌症的特征所描述的，针对单个专用肿瘤特征的各种成像方法已经在临床前研究中取得了成功，并且一些方法已经在临床试验中得到了评估。但是，这些方法在临床实践中基本上没有实现。在这篇综述中，我们描述了当前的生物医学影像学方法，用于监测接受新型靶向疗法的患者对治疗的反应，包括最有前途的未来方法的总结以及这些方法如何改善临床实践。