Cancer, a complex and multifactorial disease, presents a significant challenge to global health. Despite significant advances in surgical, radiotherapeutic and immunological approaches, which have improved cancer treatment outcomes, drug therapy continues to serve as a key therapeutic strategy. However, the clinical efficacy of drug therapy is often constrained by drug resistance and severe toxic side effects, and thus there remains a critical need to develop novel cancer therapeutics. One promising strategy that has received widespread attention in recent years is drug repurposing: the identification of new applications for existing, clinically approved drugs. Drug repurposing possesses several inherent advantages in the context of cancer treatment since repurposed drugs are typically cost-effective, proven to be safe, and can significantly expedite the drug development process due to their already established safety profiles. In light of this, the present review offers a comprehensive overview of the various methods employed in drug repurposing, specifically focusing on the repurposing of drugs to treat cancer. We describe the antitumor properties of candidate drugs, and discuss in detail how they target both the hallmarks of cancer in tumor cells and the surrounding tumor microenvironment. In addition, we examine the innovative strategy of integrating drug repurposing with nanotechnology to enhance topical drug delivery. We also emphasize the critical role that repurposed drugs can play when used as part of a combination therapy regimen. To conclude, we outline the challenges associated with repurposing drugs and consider the future prospects of these repurposed drugs transitioning into clinical application.

癌症是一种复杂的多因素疾病，对全球健康提出了重大挑战。尽管手术、放射治疗和免疫学方法取得了重大进展，改善了癌症治疗结果，但药物治疗仍然是关键的治疗策略。然而，药物治疗的临床疗效常常受到耐药性和严重毒副作用的限制，因此仍然迫切需要开发新型癌症治疗方法。近年来受到广泛关注的一项有前景的策略是药物再利用：确定现有临床批准药物的新应用。药物再利用在癌症治疗方面具有几个固有的优势，因为再利用药物通常具有成本效益，被证明是安全的，并且由于其已经建立的安全性，可以显着加快药物开发过程。有鉴于此，本综述对药物再利用中采用的各种方法进行了全面概述，特别关注药物再利用以治疗癌症。我们描述了候选药物的抗肿瘤特性，并详细讨论了它们如何针对肿瘤细胞中的癌症特征和周围的肿瘤微环境。此外，我们研究了将药物再利用与纳米技术相结合以增强局部药物输送的创新策略。我们还强调重新利用药物作为联合治疗方案的一部分可以发挥的关键作用。最后，我们概述了与药物再利用相关的挑战，并考虑了这些再利用药物转变为临床应用的未来前景。