Metastasis is a complex systemic disease that develops as a result of interactions between tumor cells and their local and distant microenvironments. Local and systemic immune-related changes play especially critical roles in limiting or enabling the development of metastatic disease. Although anti-tumor immune responses likely eliminate most early primary and metastatic lesions, factors secreted by cancer or stromal cells in the primary tumor can mobilize and activate cells in distant organs in a way that promotes the outgrowth of disseminated cancer cells into macrometastatic lesions. Therefore, the prevention, detection, and effective treatment of metastatic disease require a deeper understanding of the systemic effects of primary tumors as well as predisposing hereditary and acquired host factors including chronic inflammatory conditions. The success of immunotherapy in a subset of cancer patients is an example of how modulating the microenvironment and tumor-immune cell interactions can be exploited for the effective eradiation of even advanced-stage tumors. Here, we highlight emerging insights and clinical implications of cancer as a systemic disease.

转移是一种复杂的系统性疾病，其是肿瘤细胞与其局部和远距离微环境之间相互作用的结果。局部和全身性免疫相关变化在限制或促进转移性疾病的发展中起着至关重要的作用。尽管抗肿瘤免疫反应可能消除了大多数早期的原发性和转移性病变，但原发性肿瘤中的癌症或基质细胞分泌的因子可以动员并激活远处器官中的细胞，从而促进已扩散的癌细胞向大转移性病变中生长。因此，转移性疾病的预防，检测和有效治疗需要对原发性肿瘤的全身作用有更深入的了解，并需要遗传和获得性宿主因素，包括慢性炎症。免疫疗法在部分癌症患者中的成功是如何利用微环境和肿瘤免疫细胞相互作用来有效根除甚至晚期肿瘤的一个例子。在这里，我们重点介绍作为系统性疾病的癌症的新见解和临床意义。